5B2. Blowing out the rodmeter. This operation should be performed with the rodmeter in its extended, or operating, position. It is good practice to blow out both lines even if the tests for obstruction indicate that only one line is clogged, as foreign matter has undoubtedly entered both passages. Blow out the rodmeter in the following manner: Disconnect the hose from the static pressure valve nipple on the control unit. Pinch the

5B3. Removing solid obstructions from the rodmeter. If obstructions are not removed by blowing out the rodmeter with compressed air, the following operations will be necessary:

Raise the rodmeter to its fully housed position (Figure 5-2). Close the sea valve. Unlatch the stop bracket at the top of the hoist assembly by opening and removing the lock which secures the bracket in position above the rodmeter, and swing it to one side out of the way (Figure 5-2). Remove the lower end of the rodmeter from the sea valve extension by raising the rodmeter to the

Do not use steel wire or a drill to clean the orifices as they may score the orifices or break off in the openings.

Blow out the rodmeter as described in Section 5B2 with the exception that the rodmeter need not be extended into the sea. Have one crew member hold his hand near the orifices to detect the flow of air which indicates that the orifice and tubing are clear. Repeat the operation until all passages are clear. Align the lower end of the rodmeter with the opening in the sea valve extension and lower the rodmeter to its fully housed position (Figure 5-2).

At this point the tip of the rodmeter is approximately 1 inch above the sea valve gate. Open the sea valve. Swing the stop bracket to its normal position above the rodmeter and secure in place with the lock. It is important that the stop bracket be in position above the rodmeter at all times except during the above operation, or when the rodmeter is being replaced. Lower the rodmeter to its normal housed position or to its fully extended position as desired. Place the hoist crank in the brackets provided, and replace the deck plate over the sea valve.

5C2. Breaking out the spare rodmeter. Break out the spare rodmeter and place it alongside of the hoist mechanism so that it will be immediately available when needed.

5C3. Rumoring the clamp and guard assembly (nipple installation). (See Figure 5-4.) Loosen the hose clamps and remove the two lengths of hose from the nipples on the upper end of the rodmeter. Unscrew the longest nipple (after nipple) and plug the hole in the rodmeter with a wooden plug. Remove the

Figure 5-3. Rodmeter with valves installed.

5C4. Removing the clamp and guard assembly (valve installation). Loosen the two hose clamps (one on each hose) that secure the ends of the hose to the nipples provided on the valve assemblies at the upper end of the rodmeter (Figure 5-3). Remove the hose and clamps. Remove the two bronze nuts and bolts that secure the two clamps and the guard to the top of the rodmeter, and remove the clamps. Raise the guard and yoke assembly up against the stop bracket by means of the hoist provided for raising the rodmeter.

This is accomplished by removing the two nuts (one on each handle) that secure the valve handles to the valve stems, and by removing the handles. Make a rough sketch of the position of the valve assemblies so that they can be installed in their original position on assembly. Spread the two valve assemblies apart so that one of them can be unscrewed without interference from the other valve assembly. Unscrew and remove the lower valve assembly from the elbow which connects this valve assembly with the opening in the top of the rodmeter. Plug the elbow opening with a wooden plug. Unscrew the complete valve assembly from the other opening on top of the rodmeter, and plug this opening in the rodmeter with a wooden plug. Unscrew and remove the elbow of the lower valve assembly from the top of the rodmeter, and plug the opening in the top of the rodmeter with a wooden plug.

5C5. Installing the valve assemblies in the top of the rodmeter. (See Figure 5-3.) The spare rodmeter is equipped with nipples and a clamp and guard assembly. For those ships which have valve assemblies installed instead of the conventional rodmeter nipples, the following procedure is necessary to install the valve assemblies in the spare rodmeter:

1. Remove the clamp and guard assembly from the spare rodmeter by removing the two bronze nuts and two bolts that secure the clamps and guard in position at the upper end of the rodmeter, and remove the clamps and guard.

2. Unscrew and remove the two nipples from the top of the rodmeter.

3. Apply a coating of white lead compound to the threads of the valve assemblies to be installed.

4. Install the elbow of the lower valve assembly (previously removed from the damaged rodmeter) in the after (static) opening in the top of the rodmeter. Refer to the sketch previously made at disassembly, and tighten this elbow to its original position.

6. Disassemble the second valve assembly by unscrewing the horizontal nipple and valve assembly from the elbow and nipple assembly. Also remove the valve bottom and stem assembly from the valve body. This disassembly is necessary in order to obtain the proper clearances while installing the second valve assembly in the rodmeter.

7. Install the elbow and nipple in the forward (dynamic) opening on top of the rodmeter. Tighten until the elbow is in its original position. Refer to the sketch made previously for the position of the elbow.

8. Install the valve body and nipple into the elbow.

9. Install the valve bottom and stem assembly into the valve body, making certain that the valve stem is facing upward.

5C6. Installing the clamp and guard assembly. (See Figure 5-4.) The two clamps and the guard are stamped at their ends. These numbers should be adjacent to one another when these pieces are assembled on the rodmeter. Place the two clamps around the upper end of the spare rodmeter in such a manner that the clamps are over the knock-out pins provided at the top of the rodmeter. Place the guard between the clamps. Align the mounting holes in the three pieces, and install the two bronze bolts and nuts that secure the clamp and guard assembly to the rodmeter. Tighten the nuts securely.

5C7. Installing the spare rodmeter. (See Figure 5-4.) The following procedure should be used in installing the rodmeter:

1. If the damaged rodmeter is partially raised, push it downward until the knock-out pin rests on top of the packing gland in the sea valve extension. It may be necessary to use a heavy hammer and wooden block to start the rodmeter downward.

2. Place the tip of the spare rodmeter on top of the damaged rodmeter, being sure that the dynamic orifice in its leading edge is facing forward. Note the arrows stamped on the

3. Remove the cotter pin and the clevis pin which secure the old guard to the lifting bar on the hoist chain, and remove the old guard. Align the opening in the lifting bar with the opening provided in the guard on the spare rodmeter, and install the clevis pin and cotter pin which secure the lifting bar to the guard assembly.

4. Place the loose end of the dynamic hose over the nipple provided on the dynamic fitting on top of the rodmeter. The opposite end of this hose is attached to the pump. Secure the hose to the nipple by tightening the hose clamp on the end of the hose. Place the end of the static hose on the nipple provided on the fitting on top of the rodmeter. The opposite end of the static hose is attached to the control unit. Secure the hose to the nipple by tightening the hose clamp on the end of the hose.

5. Remove the knock-out pin from the damaged rodmeter. Push downward on the spare rodmeter to drive the damaged rodmeter downward and out of the ship.

6. Vent the system in accordance with the instructions in Section 3A3.

5D2. Period of overhaul. If possible, the pump assembly should be removed, disassembled, cleaned, inspected, lubricated, adjusted, and/or repaired, if necessary, every 45 days. If the tactical situation does not warrant servicing the pump at 45-day intervals, it should be overhauled after every patrol to keep the pump operating correctly. A shorter

5D3. Removing the pump. (See Figure 5-5.) Have the rodmeter in its secured position with the sea valve closed. Disconnect the two lengths of hose from the pump by loosening the two hose clamps (one on each hose) that secure the hose to the nipples on the pump, and remove the hose and clamps. Remove the four nuts that secure the pump to the spacer (mounting) rods, and remove the pump assembly from the spacer rods.

5D4. Disassembly of the pump assembly. (See Figure 5-7.) Following is the procedure for disassembling the pump assembly.

2. Remove the 12 screws that secure the housing cover to the housing, and remove the housing cover. Lift the rubber gasket off the housing. Turn the pump assembly over so that the impeller blades are facing downward, and rest the pump assembly on the cover jacket with the impeller blades in the opening in the cover jacket. Do not rest the impeller blades on an uneven surface as they will be damaged.

3. Remove the four screws that secure the housing jacket to the pump housing, and remove the housing jacket.

4. Loosen the two setscrews (one on each piece) that secure the coupling and the fan on the impeller shaft, and remove the coupling and fan.

6. Bend down the lug of the external toothed lock washer that secures the lock nut in position. Using the special lock nut wrench (Figure 5-6), remove the lock nut from the end of the impeller shaft. Do not place the impeller blades in a vise. Lift off the lock washer. Pull the impeller assembly out of the pump housing.

7. Insert a brass or fiber rod V inch in diameter into the pump housing from the impeller end of the pump housing and push out the two ball bearings, two spacers, thrower disk, and shield washer from the pump housing. Do not use a steel rod as the parts will become burred, and the bearings will not align properly at assembly.

1. The rotary seal bellows is disassembled from the impeller assembly when visual inspection reveals the fade of the bellows to be grooved, burred, or badly corroded.

2. Remove the eight screws that secure the impeller gasket ring to the impeller, and remove the gasket ring. Remove the gasket from the ring or from the impeller if the gasket is sticking to the impeller. Carefully pull the rotary seal bellows from the impeller and off the impeller shaft.

3. Place the impeller shaft in a soft-jawed vise in such a manner that the pin that secures the shaft to the impeller is parallel to the jaws of the vise. Using a pin punch, drive out the pin from the impeller and the, impeller

shaft. The impeller shaft is disassembled from the impeller only if a gap between the shaft and the impeller indicates that the pin that secures the shaft to the impeller has been distorted, or sheared off due to the application of too much pressure on the lock nut which secures the bearings and spacers to the impeller at a previous assembly operation.

5D6. Inspection and repair of impeller shaft. (See Figure 5-8.) Inspect the impeller shaft for straightness. Inspect the shaft for security of mounting in the impeller. The impeller shaft should be securely mounted in the impeller, and the pin that secures the shaft to the impeller should be in place. A gap between the impeller shaft and the impeller is

Figure 5-9. Checking length of rotary seal bellows

5D7. Inspection of the impeller blades. (See Figure 5-8.) Inspect the impeller blades for straightness and depth. The blades should be straight. The depth of the impeller blades on a new, impeller is 0.189 inch. If the impeller blades are worn more than 0.002 inch below the depth of the blades of a new impeller, that is, the depth of blades is less than 0.187 inch, the impeller should be replaced, or the calibration of the system will be incorrect.

5D8. Inspection of the rotary seal bellows. (See Figure 5-8.) Visually inspect the face of the rotary seal bellows. If worn, pitted; or corroded, replace the bellows and gasket. Use KR monel bellows for replacement, if available. Use monel or bronze screws on the gasket ring. Do not use stainless steel screws on the gasket ring as the steel screws corrode badly when used with monel. Check the

Figure 5-10. Stretching rotary seal bellows.

dimension from the impeller hub to the bellows face (Figure 5-9). This dimension is very critical and should be exactly 13/32-inch. If the bellows is too short (dimension more than 13/32-inch), the pump may leak excessively. If the bellows is too long (dimension less than 13/32-inch), the seal faces will wear rapidly, and may make the pump too tight. This latter fault will cause the pump to bind at low speeds.

5D9. Adjusting-the rotary seal bellows. (See Figure 5-10.) If the bellows are found to be too short, as described in Section 5D8, they may be stretched as follows: Place a thin strip of metal, such as the smooth edge of a hacksaw blade, between the folds of the rotary seal bellows. Turn the bellows around so that the metal blade will stretch the bellows uniformly. After each turn, measure the distance between the impeller hub to the bellows face. Repeat the spreading operation until the dimension between the impeller hub and bellows face is exactly 13/32-inch. When the bellows is too long, as described in Section 5D8, compress the bellows by hand (while installed on impeller shaft) until the dimension between the impeller hub and the bellows face is exactly 13/32-inch. When the rotary seal bellows is at proper dimension, the bellows face must move freely inward and outward along the shaft.

5D11. Refacing the old seal insert. (See Figure 5-11.) Place the pump housing in a lathe. Align the housing up to 0.0005 inch, using a dial indicator on the monel liner face. Take light cuts across the seal insert face until score marks are removed. Undercut the inner face at the inside diameter of the insert 0.010 inch below the face of the seal insert. Occasionally when an old seal insert is refaced, enough metal is removed so that the

Figure 5-12. Pressing out rotary seal insert.

Figure 5-13. Installing rotary seal insert.

5D12. Replacing the seal insert. (See Figures 5-12 and 5-13.) Place the pump housing on the bed of an arbor press with the large end of the housing downward. Using a special rod as shown in Figure 5-12, press out the seal insert. To install a new seal insert, place the housing on the bed of an arbor press with the small end of the housing downward. Put a moderate amount of pipe compound on the outer surface of the shoulder of the insert and on the inner surface of the opening through the housing liner. Place the new seal insert in the housing with the shouldered end

5D13. Refacing the new seal insert. (See Figure 5-11.) At manufacture, the dimensions of the seal insert are such that it may be faced to allow for removal of burrs or score marks from the seal surface after the pressing operation. This precaution is also taken to allow

Figure 5-14. Checking rotary seal insert.

for facing the seal in the event it is not pressed true in the housing. Reface a new seal insert as follows: Place the pump housing in a lathe. Align the housing up to 0.0005 inch, using a dial indicator on the monel liner face. Take light cuts across the seal insert face until the proper dimension of 0.764 inch is reached and the face of the seal insert is smooth. This dimension is the distance from the monel liner face of the housing to the face of the seal insert, and is determined with a depth gage as shown in Figure 5-14.

5D14. Inspection of the seal ring. (See Figure 5-7.) Visually inspect the seal ring. The ring must be perfectly flat, or it should be 0.0005 inch thicker at its outer edge. If it is worn on either side, the ring should be replaced. The seal ring should always be

5D15. Inspection and repair of the thrower disk and shield washer. (See Figure 5-7.) The thrower disk and shield washer need not be replaced unless they are badly worn or bent. Using a straightedge, inspect the pieces for flatness. Visually inspect the thrower disk and shield washer for burrs. Remove nicks from the inner surfaces of the thrower disk and shield washer with a bearing scraper. Remove score marks from surfaces with a finecut file.

5D16. Cleaning and inspection of the bearings. (See Figure 5-7.) Thoroughly clean the bearings with Navy-approved cleaning fluid. Dry the bearings thoroughly. In cases where the grease has become hardened within the bearing, the bearing should be allowed to soak in the cleaning fluid until the grease has softened, and then swished back and forth in the cleaning fluid until all grease and dirt are removed from the bearing. Visually inspect the bearings for pitting resulting from corrosion, and if they are pitted, replace the bearings. The bearings should be smooth and operate freely. Turn the bearing by hand, and note any clicking noise which indicates a cracked ball, or a piece of metal or dirt within the bearing. If the bearing is thoroughly clean, and clicking or binding exists when the bearing is rotated by hand, the bearing should be replaced: If the bearing is worn so that there is excessive side play, or excessive end play between races, it should be replaced. After cleaning and inspection, oil the bearings with light oil, and pack the bearings with grease, Navy, Symbol 14L3. Wrap the bearings in waxed paper until they are to be assembled.

5D18. Assembling the shaft and impeller. (See Figure 5-8.) Place the impeller shaft in the impeller hub. Align the hole in the shaft and the hole in the impeller hub, and install the pin that secures the shaft to the impeller hub. Be sure that the ends of the pin are flush with the impeller hub, and that the surfaces at the ends of the pin are smooth.

5D19. Installing the rotary seal bellows. (See Figure 5-8.) Place the rotary seal bellows on the impeller shaft with the recessed end of the bellows toward the impeller. Install the rubber gasket over the seal bellows and up against the impeller (not inside the bellows). Place the gasket ring over the bellows. Align the mounting holes in the gasket ring and the holes in the impeller, and install the eight screws which secure the gasket ring to the impeller. Check the dimensions of the rotary seal bellows as described in Section 5D8.

5D20. Installing the impeller assembly. (See Figures 5-7 and 5-15) Place the seal ring (micarta ring if available) over the impeller shaft and up against the face of the rotary seal bellows. Place the pump housing over the impeller shaft with the large end of the pump housing toward the impeller. Place the thrower disk on the impeller shaft with the large flat surface of the ring toward the impeller. Install the shield washer on the impeller shaft with the flat surface of the washer facing away from the impeller. Install the inner ball bearing on the impeller shaft with the shield end of the bearing toward the impeller. Place the inner and outer bearing spacers on the shaft so that they are adjacent to the inner ball bearing just installed. Fill the bearing spacers one-half full with grease, Navy Symbol 14L3.

Install the outer bearing on the impeller shaft with the shield end of the bearing facing away from the impeller. Carefully press the ball bearing on the impeller shaft by hand until the bearing is aligned with, and adjacent to, the inner and outer bearing- spacers previously installed. Place the toothed lock washer on the impeller shaft with the teeth facing upward (away from the impeller). Place the lock nut on the impeller shaft with the chamfered end of the nut toward the impeller. Using the special lock nut wrench (Figure 5-6), and holding the impeller blades with one hand, tighten the lock nut reasonably tight.

Do not force-tighten this nut, or the pin that secures the impeller shaft to the impeller hub will be sheared off.

Align one of the slots in the lock nut with one of the teeth in the lock washer, and bend the tooth upward to secure the lock nut in position.

5D21. Installing the end cap. (See Figure 5-7.) Place the end cap over the end of the impeller shaft and up against the small end of the pump housing. Align the mounting

Figure 5-16. Checking impeller clearance.

5D22. Checking the impeller blade clearance. (See Figure 5-16.) Using a thickness gage, check the clearance between the housing end of the impeller blades, and the monel liner of the pump housing as shown in Figure 5-16.

5D23. Installing the fan and coupling. (See Figure 5-7.) Place the fan on the impeller shaft with the hub of the fan toward the impeller. Align the setscrew in the fan hub with the flat side of the impeller shaft, and tighten the setscrew to secure the fan on the shaft. Place the half-coupling on the end of the impeller shaft with the lugs of the coupling facing away from the impeller. Carefully align the end of the coupling with the end of the impeller shaft and tighten the setscrew that secures the coupling to the impeller shaft. The face of the coupling must be flush with the end of the impeller shaft.

5D24. Installing the housing jacket. (See Figure 5-7.) Place the housing jacket in position over the pump housing, and install the four screws that secure the housing jacket to the pump housing.

5D25. Installing the pump cover. (See Figure 5-7.) Place the rubber cover gasket in the groove provided in the impeller end of the pump housing. Place the finned pump cover in position on the impeller end of the pump housing. Align the cover so that the vent cock is directly opposite the drip fitting on the pump housing. Install the 12 screws that secure the cover to the pump housing. The vent cock should be repaired at this time. Inspect and clean the vent cock as follows: Remove the nut or cotter pin that secures the spring and valve assembly in the vent cock body. Lift the valve assembly from the vent cock body. Clean corrosion from all parts of the vent cock, and lubricate with a small amount of waterproof grease.

5D27. Installing the pump. (See Figure 5-5.) Before installing the pump, test it under pressures up to 200 pounds per square inch at a speed as low as 1 knot in accordance with the instructions given in Chapter 7. Slide the pump assembly on the spacer rods, making certain that the went cock on the pump is facing upward. Be sure that the coupling on the pump drive motor shaft is flush with the end of the drive shaft. Place the rubber block in one half of the pump coupling. Move the pump to the left until the two halves of the coupling are properly engaged; then install the four nuts that secure the pump assembly on the spacer rods. Install the dynamic hose from the control unit on the upper nipple on the pump, and tighten the hose clamp to secure the hose to the nipple. Install the dynamic hose from the rodmeter on the lower pump nipple, and tighten the hose clamp to secure the hose on the nipple. Vent the system in accordance with the instructions given in Section 3A3.

5E2. Inspection and repair of the brushes. Visually inspect the brushes. They should show a polished surface on the end that contacts the commutator. The brushes should not be less than 3/8-inch long from the contact end to the shoulder where the brush spring is attached. Brushes showing wear nearing the 3/8-inch dimension should be replaced. If the brush contact surface is pitted, smooth off the surface, using fine sandpaper wrapped around a cylindrical object. The brushes can be

5E3. Installing the brushes. (See Figures 5-17 and 5-18.) Place the lower brush in the hole provided in the lower side of the motor. Compress the brush tension spring by hand, and install the cap which secures the lower brush in the motor. Install the upper brush in the hole provided in the top of the motor in the same manner. Install the pipe plug in the hole in the bottom of the rotary distance transmitter case. Install the case cover.

5E4. Removing the armature. (See Figures 5-17 and 5-19.) Remove the pump (see Section 5D3.) Remove the brushes (see Section 5E1). Remove the two screws that secure the gear guard to the rotary transmitter case and remove the gear guard. Loosen the socket head setscrew that secures the drive motor coupling on the motor shaft, and remove the coupling and rubber spacer. Remove the four screws that secure the back end shield on the motor

5E5. Inspection of the bearings. (See Figure 5-19.) Visually inspect the two bearings on the armature shaft for evidence of pitting due to corrosion. Turn the bearings by hand. They should turn easily and freely. A clicking noise indicates that one or more of the balls is cracked, and the bearing must be replaced. A damaged bearing is removed by using a bearing puller. Press the replacement bearing onto the shaft in place of the damaged bearing.

5E6. Assembly of the armature. (See Figures 5-17 and 5-19.) Align the worm, spacers, and bearing on the end of the armature shaft with the opening in the back end shield, and carefully push the armature assembly into the back end shield. Place the armature inside the motor, being careful when inserting the shaft through the opening in the front end shield. Align the mounting holes in the back end shield with the holes in the field ring, and install the four screws that secure the back end shield to the field ring of the motor. Turn the pump drive shaft by hand to be sure that the armature and gears are turning freely. Install the gear guard. Install the two brushes (see Section 5E3). Install the coupling on the armature shaft and secure with the setscrew provided. Install the rubber spacer. Install the pump (see Section 5D27).

5E7. Removing the pump drive motor as a unit. See Figure 2-8.) Disconnect the hose and remove the pump (see Section 5D3). Disconnect the armature and field wires from the

5E8. Installing the pump drive motor. (See Figures 5-17 and 2-8.) Align the two upper spacer rods with the motor mounting bracket, and slide the motor assembly to the right as far as the stop on the spacer rod will allow. Make sure that the gears at the left end of the motor are properly meshed and that the spacer rod is against the motor mounting bracket. There should be a slight amount of backlash between the two external gears. If the gears do not mesh properly when the stop is against the motor mounting bracket, it will be necessary to relocate the stop. This is accomplished as follows: Drill out the pin that secures the stop on the spacer rod. Slide the motor assembly to the right until the gears at the left end of the motor are properly meshed. Slide the stop over against the motor mounting bracket and locate the pinhole. Drill a hole through the spacer rod. Install a new pin through the stop and the spacer rod. Install the gear guard. Connect the two armature and the two field wires to the terminal block on the counter mounting plate inside the rotary distance transmitter case. The terminal block and terminals on the wires are marked for the location of wires. The corresponding terminals are marked as follows A+, A-, F+, and F-. Install the pump (see Section 5D27).

Figure 5-20. Removing transtat.

5F2. Installing the transtat assembly. (See Figure 5-20.) Place the new transtat assembly with its assembled gear in position in front of the rotary distance transmitter in such a manner that the wires can be connected. Place the three wires, previously marked, on their corresponding marked posts, and secure each terminal with a flat washer and nut. Place the transtat assembly in position on the mounting plate provided on the back of the rotary distance transmitter case, making certain that the gears are meshed, and install the four screws and toothed lock washers that secure the transtat assembly in the case. Rotate the transtat gearing by hand over its entire range and note the position of the center brush of the transtat at the instant the upper and lower limit switches are operated. The brush must still be on the transtat winding. Do not force the gearing beyond the point where the switches are actuated. If the brush is not on the winding at each position, loosen the three clamp screws passing through the core; shift the core radially to the proper position, and tighten the screws. Recheck for proper operation.

5G2. Removing the follow-up motor. (See Figure 5-21.) Disconnect the wires from the terminal block on the motor. Tag the wires for ready identification. Remove the three

5G3. Exchanging the pinion and spur gear assembly. The replacement of the spur gear on the follow-up motor follows exactly the same procedure as that described in Section 5M5 for the gear replacement of the lead screw drive motor.

5G4. Installing the follow-up motor. (See Figure 5-21.) Place the follow-up motor assembly in position on the mounting plate. Install the three screws and toothed lock washers that secure the motor to the mounting plate. Connect the wires to the terminal block on the motor. Tighten the terminal screws. Install the cover on the case.

5H2. Replacing the rectifier stacks in the rectifier assembly. (See Figure 5-22.) Remove the four nuts (two at each end) that secure the brackets to the rectifier studs, and remove the brackets. Save any spacer washers that may be installed on the rectifier studs for replacement on the new rectifiers. Place the spacer washers, if used on the old rectifier

1. TERMINAL BLOCK
2. FOLLOW-UP MOTOR
3. TRANSTAT MOUNTING PLATE
4. TRANSTAT, ASSEMBLY
5. MOTOR BRACKET

Figure 5-21. Removing follow-up motor.

This is important in order that the same space between the mounting brackets will be maintained.

Place the two rectifiers in the mounting brackets in the same position as the previously removed rectifiers, making certain that the name plates are facing in the same direction, and install the four lock washers and nuts (two at each end) that secure the brackets to the rectifier studs. If the replacement rectifiers have square plates (slightly higher current capacity) be sure that the bakelite spacer, furnished with this type, is properly installed between the two stacks. The spacer prevents the stacks from touching if they should become loose during operation. The angle brackets provided are held between the inside face of the mounting brackets and the adjacent nuts. Two spacer washers may be

1. RECTIFIER STUD
2. NUT
3. LOCK NUT
4. ARMATURE RECTIFIERS
5. MOUNTING BRACKET
6. BRACKET SCREW
7. COUNTER MOUNTING PLATE
8. FIELD RECTIFIER
9. COUNTER MOUNTING PLATE WITH MOTOR TERMINAL BLOCK
Figure 5-22. Rectifiers installed.

Be sure to hold the lock nut adjacent to the inside of the bracket while tightening the outer nut to prevent the distortion of the plates.

5J2. Installing the distance transmitter. (See Figure 5-23.) Place the transmitter on the

1. DYNAMIC PRESSURE VALVE
2. VENT COCK
3. BYPASS VALVE
4. VENT COCK
5. STATIC PRESSURE VALVE
Figure 5-24. Valves in position for adjusting contacts.

Clean the contact points in the following manner: Insert a piece of ordinary note paper between the contact points. Manually press the contact arm against the paper and adjacent contact point, and drag the paper across the points. This will usually remove any film of oil or dirt which may be present on the points. If this does not stop arcing between the points, clean the contact points with fine crocus paper or with a jeweler's file. Operate the system on the static head to determine whether this procedure has remedied the trouble.

5K2. Checking the position of the contact arm. (See Figure 5-25.) Remove the cover from the control unit case and hang it on the lower dowel pin. Place the valves in position for adjusting the contacts (Figure 5-24.) This places the static pressure only on both sides of the bellows, insuring that it is in the neutral, or center, position. Unless otherwise specified, all adjustments on the control unit are made with the valves in this position. Adjustments can be made while the ship is underway on the surface, but not while submerged. Back off screws No. 2 and No. 7 until

1. TERMINAL LUG A
2. ADJUSTABLE THUMB SCREW A
3. CONTACT SCREW A
4. CONTACT POINT A
5. CONTACT POINT B
6. CONTACT SCREW B
7. ADJUSTABLE THUMB SCREW B
8. TERMINAL LUG B
9. EXTERNAL CONTACT ARM
Figure 5-25. External contact arm in center position.

the stationary contact levers are completely open. Check to see that arm No. 9 is centered between stationary contact points No. 3 and No. 6. Manually move arm No. 9 upward and downward to see that it works freely and returns to the center position. If it is in good order, adjust the contact points as described in Sections 5K3 and 5K4. If the contact arm does not move freely or if it cannot be moved to each side of its center position because the internal lever strikes a stop rod, the interfering stop rod will have to be backed off slightly in the manner described in Sections 5K9 and 5K10. If the stop rods do not interfere and the arm still does not return to the center position, it will be necessary to attempt to position the contact arm by adjusting the

contact arm clamps. This is performed in the following manner: position.Remove the pipe plug from the end of the case to make the inner clamp accessible, as shown in Figure 5-26. Slightly loosen the inner clamp screws. Slightly loosen the clamp screws from the outer clamp. Carefully hold the arm in the center position with one hand, and tighten the outer clamp screws so that an equal space is maintained between the clamp and the end of the arm. Then carefully tighten the inner clamp screws in the same manner. Clamp screws must be securely tightened, and equal space must be maintained between the inner surfaces of the contact arm and the bearing plate at the bellows housing. If the arm continues to bind, it is an indication of corrosion or damaged inner parts of the bellows assembly or faulty bellows linkage installation. If this is the case, disassemble the bellows as described in Sections 5K12 through 5K16. Inspect, clean, and repair parts if necessary, as described in Section 5K17. Assemble the bellows as described in Sections 5K18 through 5K29. Adjust the contacts as described in Sections 5K3 and 5K4. Reset the stop rods as described in Section 5K8, 5K9, and 5K10.

Set the valves and vent cocks as shown in Figure 5-24. This insures equal pressure on the bellows. Deenergize or turn off the 2Y circuit on the control board. Remove the cover from the rotary distance transmitter, and disconnect either the 2Y¹ or the 2YY¹ wire from the left end of the terminal block. This is done to prevent the pump from operating while adjustments are being made. Energize the 2Y circuit by turning the control panel switch to the ON position. Manually push down the external contact arm until the transtat brush arm in the rotary distance transmitter travels approximately one-third of its distance from the lower limit switch. This allows sufficient movement of the brush arm while making adjustments. Turn down screw No. 5 until the follow-up motor in the rotary distance transmitter starts running smoothly. When the upper contacts first touch, the follow-up motor will operate unevenly. Continue to turn down screw No. 5 slowly, three-quarters of the distance between the holes in the head of the screw (approximately 15 to 18 degrees). Secure screw No. 5 in this position by means of the lock screw in front of the contact mounting bracket.

5K4. Adjusting the lower contact without using the lamp. (See Figure 5-2$.) Break the electrical contact on the upper lamp socket by loosening the terminal screw and removing one wire from the terminal. This is done so that the transtat motor will operate when both contacts are touching. Normally the transtat motor will not operate when both contacts are touching the: contact arm. Turn up screw No. 6 until the follow-up motor in the rotary distance transmitter just starts operating, then back off screw No. 6 slowly, three-quarters of the distance between the holes in the screwhead (approximately 15 to 18 degrees). Secure screw No. 6 in this position by means of the lock screw in front of

the contact mounting bracket. Reinstall the wire terminal on the terminal of the upper lamp socket. This is necessary in order that the follow-up motor will run down. The follow-up motor should then run down until the transtat brush arm hits its lower limit switch. If the brush arm does not hit the lower limit switch and the follow-up motor does not stop, it is an indication that the contact points were not set properly. Personnel will have to reset the contact points, being very careful to slowly turn the contact adjusting screws the proper amount as discussed above.

5K5. Preparing the system before adjusting contacts with the test lamp. This is an alternate method of adjusting the contact points. Two lamps are provided to make this adjustment. These lamps are mounted in a bracket in the upper right side of the control mounting plate. Use only one lamp when making this adjustment. The other lamp is a spare only. Set the valves and vent cocks as shown in Figure 5-24, in order to insure equal pressure on the bellows. Deenergize, or turn off the 2Y circuit switch on the control panel.

5K6. Adjusting the upper contact using the lamp method. (See Figure 5-27.) Remove one of the lamps from the bracket in the rear of the case. Install the lamp in the upper socket. Turn down screw No. 5 until the lamp burns without flickering. Then slowly continue to turn down screw No. 5 for three-quarters of the distance between the holes on the screwhead

1. TERMINAL LUG A
2. TERMINAL LUG B
3. LAMP
4. CONTACT POINT
5. CONTACT SCREW B
6. ADJUSTABLE THUMB SCREW B
7. LOWER LAMP SOCKET
Figure 5-28. Adjusting lower contacts by the lamp method.

5K7. Adjusting the lower contacts, using the lamp method. (See Figure 5-28.) Remove the test lamp from the upper socket and install it in the lower lamp socket. This breaks the contact in the upper socket, and permits proper adjustment of, the lower contact. Turn screw No. 6 slowly upward until the lamp glows; then slowly back off screw No. 6 until the lamp does not glow. Continue to back off screw No. 6 slowly for three-quarters of the distance between the holes in the screwhead (approximately 15 to 18 degrees). Secure the screw in this position by means of the lock screw in front of the mounting bracket. Remove the lamp from the socket and install it in the carrying bracket back of the control mounting plate. Remove the wires from the upper and lower lamp socket terminals and install them in their original position on the sockets as shown in Figures 5-27 and 5-28. If the follow-up motor in the rotary distance transmitter does not drive the transtat brush arm to the lower limit switch, it is an indication that the contacts are not properly adjusted, and that the operation of the adjusting contact points will have to be repeated. Check the setting of the upper and lower stop rods and reset if necessary (see Sections 5K8, 5K9, and 5K10) before operating the log. The contact setting made may be thrown off adjustment if the stops are incorrectly set.

5K8. Adjustable stop rods. (See Figure 529.) Two adjustable stop rods are provided in the bellows assembly to limit the upward and downward motion of the bellows, thus preventing possible damage to the interior parts of the bellows housing, and to the contact mechanism at times of excessive pressure differences. These pressure differences often cause the bellows to stretch slightly from the newly installed position and consequently necessitate adjustment of the stops as well as of the contact points. Older type bellows assemblies are equipped with stop rods that are only partly threaded throughout the length of the rod. In the event that these old

type rods become damaged or stripped, the complete bellows assembly must be disassembled to remove them. In the newer type of bellows assembly, the stop rods are threaded throughout the entire length and may be removed without dismantling the bellows housing.

5K9. Setting the lower adjustable stop rod. (See Figures 5-29, 5-30, and 5-3l.) Remove the cover from the control unit case. Unscrew and remove the lower cap to make the lower stop rod accessible. Remove the pipe plug from the dower side of the case. Using the socket wrench, loosen the lock nut that secures the stop rod in position. Place a finger on the contact arm and hold the arm slightly downward. Turn the lower stop rod inward (clockwise) until the stop rod contacts the bellows stud and starts to push the contact arm upward. Continue to turn the stop rod until the gap between the upper contact points is reduced to approximately 1/32-inch.

Tighten the lock nut to secure the stop rod in this position. Set the valves and vent cocks as shown in Figure 5-42 (Position 7). This causes the water to force the bellows downward. The upper contacts should be open approximately 1/32-inch. If the points are not open this amount, reset the lower stop rod. Make certain that the lock nut on the lower stop rod is tight. Install the lower cap. Turn the valves and cocks to the desired position.

5K10. Setting the upper adjustable stop rod. (See Figure 5-31.) Remove the pipe plug from the upper end of the case to make the stop rod accessible. Remove the cap from the top of

the bellows housing. Using the socket wrench as illustrated in Figure 5-31, loosen the lock nut on the stop rod. Turn the stop rod downward (clockwise) while holding the contact arm up against the upper contact screw until the stop rod contacts the inside of the bellows head. Continue to turn the stop rod until the gap between the lower contacts is reduced to approximately 1/32-inch; then tighten the lock nut on the stop rod. Set the vent cocks and valves as shown in Figure 5-42 (Position 3). Water pressure will now force the, contact arm upward. The lower contacts should be open approximately 1/32-inch. If the contacts are not open this amount, reset the upper stop rod. Make certain that the lock nut on the stop rod is tight. Install the cap on the bellows housing. Turn the valves and vent cocks to the desired position. Check the operation of the system by operating it on the static head as described in Section 5A2.

5K11. Checking the control unit after adjustment. Check the control unit, after adjusting the contact point and setting the stop rods, in order to make certain that the unit is operating properly. Perform the following operations: Deenergize the 2Y circuit by turning the switch on the control panel to the OFF position. Reconnect the 2Y¹ or 2YY¹

5K12. Removing the control unit from its case. (See Figure 5-32.) Remove the cover retaining screws and the cover. Remove the static and dynamic hose from the nipples.

5K13. Removing the bellows assembly from the plate. (See Figure 5-33.) Disconnect the pigtail wire from the terminal on the auxiliary center contact block. Remove the handle screws and the two handles. Unscrew and remove the handle studs that secure the bellows housing to the mounting plate, and remove the studs and complete bellows assembly. Be careful that the contacts on the external contact arm are not damaged.

5K14. Removing the bellows housing corer. (See Figure 5-34.) Remove the external arm clamp retaining screws and clamps, and remove the contact arm. Remove the three screws that secure the housing and cap with the lower adjustable stop screw to the housing cover. Drain the water from the bellows. Remove the cap screw from the bellows extension post, and the ten housing cover screws and lift the housing cover from the assembly.

5K15. Disassembly of housing cover. (See Figure 5-38.) Remove the shoulder screw that secures the shaft seal bellows to the contact lever shaft. Detach the two pillow blocks and bearing assemblies from the housing cover after removing the shoulder screws. (The external contact arm was removed previously.) It may be necessary to tap the end of the contact arm shaft lightly with a soft hammer or wooden block to loosen the bearings and sockets. Remove the contact lever shaft. Detach the bellows seal cap after removing the three seal cap screws. Remove the shaft seal bellows, bellows stud, and gasket.

5K16. Disassembly of the bellows housing. (See Figure 5-43.) Remove the screws that secure the bellows holding ring to the housing, and remove the ring. Lift the bellows and

the bellows gasket from the housing. Unscrew and remove the cap, gland liner, packing, and stop rod from the top of the housing.

5K17. Inspection and repair. Examine the gaskets for cracks and torn edges. Replace any damaged gaskets. Examine the contact arm shaft for score marks. Remove any scoring with an oilstone or crocus paper. Examine the threads of the adjustable stop rods. I the threads are slightly damaged, chase them with a stock and die. Replace badly damaged stop rods. Carefully examine the pressure bellows and shaft seal for cracks or pin holes. Fill the bellows with kerosene and note any evidence of seepage, which indicates cracks or holes. Replace damaged bellows. If the bellows does not leak, thoroughly clean the kerosene from

the bellows to prevent damage to any rubber parts. Carefully examine the bearings; Turn the bearings slowly by hand. They should turn freely. A clicking noise and binding indicate cracked balls.

5K18. Installing the pressure bellows in bellows housing. (See Figure 5-35.) Place the bellows gasket in the recess provided in the bellows housing. Carefully place the bellows on the top of the gasket so that the bellows flange is properly seated over the gasket. Place the bellows holding the ring over the bellows. Align the mounting holes and install the ten screws that secure the ring to the housing. Check the length of the pressure bellows with the bellows extension post installed. Adjust the free length of the bellows so that the top of the extension post projects 31/32-inch outside of the outer (machined) surface of the bellows housing.

5K19. Assembling and installing the bellows housing cover. (See Figures 5-37, 5-38, and 5-39.) Mount the seal bellows and stud with a gasket in the housing cover. Place the cover with a rubber gasket on the bellows housing. Then carry out the following procedure:

1. Align the seal bellows stud with the bellows extension post, and loosely install the cap screw that secures the seal bellows stud

to the bellows extension post. Tighten the seal bellows cap retaining screw.

2. Assemble the ball bearing in the pillow blocks (one to each block) and install the ball bearing retainers on the pillow blocks. Assemble the pillow blocks on the ends of the contact lever shaft (one at each end), then place the contact lever shaft in position over the seal bellows and adjacent to the bellows housing cover with the side of the shaft marked TOP toward the cover. Secure the pillow blocks to the cover with four screws (two to each block).

3. Install the seal bellows shoulder screw through the hole in the contact lever shaft, and tighten the screw securely.

4. Tighten the cap screw that secures the seal bellows stud to the bellows extension post.

5. Assemble the lower adjustable stop screw in the following manner: Install the

6. Assemble the upper adjustable stop screw in the housing cap in the same manner as the lower stop screw. Be sure that the stop screw is well backed out of the cap. Install the housing cap with its assembled stop screw on top of the bellows housing.

5K20. Checking the bellows assembly for friction. Temporarily install the external

5K21. Installing external contact arm. (Figures 5-40 and 5-41.) Place the external contact

arm in position on the contact lever shaft. Install the contact, arm clamps, making certain that the assembly marks on the clamps correspond with those on the arm. Install the four zinc-plated steel screws (two to each clamp) that secure the arm clamps to the external contact arm. Be sure that there is

clearance between each clamp and the adjacent ball bearing retainer.

5K22. Installing the bellows assembly on the mounting plate. (See Figures 5-32 and 5-33.) Carefully place the bellows housing on the mounting plate. Align the mounting holes

and install the four handle studs that secure the housing to the plate. Remove the terminal screw from the right side of the auxiliary center contact block. Lift of f the wire, and place the pigtail connection on the block. Place the wire over the pigtail and install the terminal screw. Place the handles in position on the studs, and install the handle retaining screws.

5K23. Aging the bellows. (Figure 5-42.) Aging the control unit bellows is necessary any time a new bellows is installed, or if the old bellows has been bent out of its normal position. The bellows, like any metal spring, will return to a certain position when an applied pressure is released, unless the pressure has been sufficient to bend it and cause the bellows to set in a new position. If there are stresses retained in the metal from bending or stretching, the bellows will not return at once to the original position, but may creep slowly to that point. To be certain that all stresses are removed from the bellows it should be put through an aging operation. The aging operation consists of impressing a pressure first on the inside of the bellows and then on the outside, while gradually reducing the impressed pressure to zero.

5K24. Installing the control unit in its case. (See Figure 2-7.) Lift the control unit into the control unit case, and secure with the three screws and lock washers. Connect the lugs on the ends of the electrical leads to the terminal block on the upper right of the mounting plate.

5K25. Installing the piping assembly. (See Figure 2-7.) Loosen the gland nuts on top of the control unit case; and place the nipples through the top of the case and into the top of the bellows housing, using a small amount of pipe compound on the threads. Tighten the nipples securely so that the tops of the lower half of the unions are parallel. Place the valve piping assembly in position on top of the nipples, with the copper tubes inside the nipples, and tighten the unions securely. Test the complete unit for leaks with 300 pounds per square inch of water pressure. (The bypass valve must be open.) Place the hose- from the rodmeter on the static nipple (right-hand). Place the hose from the pump on the left-hand nipple and tighten the hose clamps. Fill the system with water and vent

it as described in Section 3A3. Center the contact arm, adjust the contact points and stop screws (see Sections 5K2, 5K3, 5K4, 5K9, and 5K10). In this case, the top contact adjusting screw is advanced only 1/2-hole, and the bottom screw is backed off 1/2-hole. The stop screws in the modified control unit are adjusted in the same manner as the stop rods in the older installation, except that the special stop rod wrench and screwdriver are not needed. Place the cover in position on the control unit case and secure with the cover retaining screws.

Figure 5-45. Piping assembly, new installation.

5. Assemble the left-hand street ell, nipple, and fixed block, and install the left-hand street ell in the left-hand T-fitting. Use pipe compound.

6. Assemble the pipe fitting into the right-hand street ell, using pipe compound.

7. Slide the gland nut, bakelite washer, rubber slip joint washer, and movable block onto the pipe nipple.

8. Align the fixed and movable blocks, and loosely install the four lower movable block screws.

5L2. Modifying the control unit piping assembly. (See Figures 5-45 and 5-46.) Modify the control unit piping assembly as described in the following steps:

1. Unscrew and remove the vent cocks.

2. Remove the elbows, but leave the elbow nipples installed in the cross-connector.

3. Install T-fittings in place of the elbows in the cross-connector. Use only a small amount of pipe compound on the threads.

10. Install the remainder of the block retaining screws and tighten all screws.

11. Hold the blocks with a wrench and tighten the gland nut securely.

12. Test the complete unit for leaks with 300 pounds per square inch of water pressure. The bypass valve must be open.

5L4. Replacing a damaged diaphragm. (See Figure 5-45.) Hold the movable and fixed blocks with a wrench, and loosen the gland nut. Remove the two top screws from the movable block, and loosen the remainder of

5M2. Replacing the pointer and dial. (See Figure 5-47.) Remove the cover retaining screws, and remove the case cover. Remove the hub cap from the pointer hub. Remove the screw that secures the pointer hub to the, speed transmitter shaft and remove the pointer assembly. Remove the six screws that secure the dial to the mounting studs and remove the dial. To install the dial, position it on the mounting studs and install the dial retaining screws. Place the pointer on the shaft of the transmitter shaft, and secured it with the screw provided. Set the pointer to exact zero, if necessary, as described in Sections 5M51 and 5M52. Install the pointer hub cap. Place the cover in position on the case and install the cover retaining screws.

5M3. Testing the lead screw drive motor. (See Figure 5-48.) Test the operation of the lead screw drive motor in the following manner: Remove the cover from the case. Disconnect the lead from the center terminal of the motor. This terminal is marked C. Rotate the gear by hand until the pointer reads several knots. Using a screwdriver, alternately short circuit the terminals marked CW and CCW with the center terminal. The motor

5M4. Removing the lead screw drive motor. (See Figure 5-48.) Remove the cover from the case. Disconnect the wires from the motor terminal, and tag the wires for ready identification. Remove the three screws and toothed lock washers that secure the motor bracket to the main mounting plate, and remove the motor assembly.

5M5. Replacing the lead screw drive motor. (See Figure 5-49.) Remove the lead screw drive motor (see Section 5M4). Remove the two fillister head screws that position the

Figure 5-48. Lead screw drive motor removed.

Figure 5-49. Replacing lead screw drive motor, Step 1.

pin and washer from the micarta gear son the new motor, as the washer interferes with the installation of the reduction gear assembly. Place the reduction gear assembly from the old motor on the shaft of the new motor, and install the stud nut. Install the washer and retaining pin on the micarta gear shaft.

Place the new motor with its assembled reduction gear as shown in Figure 5-51 in position in the motor mounting bracket. Install the two fillister head screws that position the motor in its bracket. Install the two screws, lock washers, and nuts that secure the motor (Figure 5-49).

5M7. Replacing the mileage counter. (See Figure 5-52.) Turn the operating shaft of the dimmer rheostat so that its forked end clears the rheostat shaft extension. Remove the 10 mounting screws that secure the main mounting plate to the case, and lift the unit out of the case. Disconnect the outside source lead wires from the terminal block. Remove the pointer and dial (see Section 5M2). Remove the four screws that secure the mileage counter to the top mounting plate, and remove the counter. Transfer the counter gear to the new counter. Place the new counter in position on the top mounting plate, and install the four counter retaining screws. Install the dial and pointer (see Section 5M2). Place the unit in its case (see Section 5M50).

5M8. Removing the top mounting plate. (See Figure 5-52.) Remove the mileage counter (see Section 5M8). Remove the tapered pin from the counter driving worm as shown in Figure 5-52, and remove the worm from the self-synchronous repeater shaft extension. Unscrew and remove the top support stud from the upper left corner of the mounting plate. Remove the screws and lock washers that secure the top mounting plate to the studs on the main mounting plate. Remove the two handle retaining screws from the upper right handle. The handle screws are staked at assembly. Swing the top mounting plate to one side out of the way.

5M9. Removing the brush block assembly. (See Figure 5-53.) Remove the top mounting plate (see Section 5M8). Remove the two screws that secure the brush block as to the studs on the main mounting plate, and carefully remove the brush block to disengage the brushes from the slip rings of the slip ring and contact assembly. Disconnect the

5M10. Replacing the spiral take-up spring. (See Figures 5-53 and 5-54.) Remove the top mounting plate as described in Section 5M8. Unscrew and remove the pin screw from the second follow-up driving gear at the left side of the spring. Loosen the setscrew that secures this second follow-up driving gear to the jackshaft. Hold the large follow-up driving gear while lifting the small follow-up

1. MAIN MOUNTING PLATE
2. TOP BRACKET
3. TAKE-UP SPRING HOOK
4. SECOND FOLLOW-UP GEARS
5. BEARING PLATE
6. SPIRAL TAKE-UP SPRING
7. BRUSH SPRING
8. FOLLOW-UP CONTACT ASSEMBLY
9. BRUSH BLOCK
10. BRUSHES
11. SLIP RING AND CONTACT ASSEMBLY
12. DIFFERENTIAL TOP BRACKET
13. JACKSHAFT
14. FIRST FOLLOW-UP DRIVEN GEAR
Figure 5-53. Slip ring and contact assembly, brush block removed.

gear from the jackshaft to prevent the spring from unwinding too rapidly. Gradually release the large gear to permit the spiral takeup spring to unwind gradually. Disengage the end of the spring from the hooks provided on the top mounting bracket and on the hub of the large second follow-up driving gear. Install the new spring in the following manner:

Engage the hole in one end of the spring in the hook on the hub of the large second follow-up driving gear as shown in Figure 554. Turn the large gear by hand to wind up the spring on the gear hub. Hook the loose end of the spring on the hook provided on the top mounting bracket as shown in Figure 5-54. Turn the gear until the spring is tightly wound, and then back off the gear three-quarters of a turn to give the spring the proper tension. Hold the large gear and spring in this position while installing the small second follow-up driving gear on top of the jackshaft. Align the pin screw hole and install the pin screw and setscrew to secure the small gear on the jackshaft.

5M11. Removing the follow-up contact assembly. (See Figure 5-55.) Remove the brush block assembly (see Section 5M9). Remove

5M12. Removing the slip ring and contact assembly. (See Figure 5-55.) Remove the follow-up contact assembly as described in Section 5M11, in order to get proper clearance for the removal of the slip ring and contact assembly. Remove the pin screw and loosen the setscrew that secures the slip ring and contact assembly to the differential shaft. The slip ring and contact assembly is removed as a unit (see Figure 5-57).

5M13. Repairing the follow-up contact assembly. (See Figure 5-56.) Under ordinary circumstances the follow-up contact assembly is replaced as a unit. However in an emergency the follow-up contact can be replaced as follows: Remove the screws from the bakelite disk, and unsolder the lead wire from the contact arm. Place the new contact arm in position on the bakelite disk, and secure with the screws provided. Solder the lead wire to the contact.

5M14. Repairing and adjusting the slip ring and contact assembly. (See Figure 5-57.) Smooth the contact points with a jeweler's file, and remove fine particles; oil, or grease with clean cloth or paper. If .the contact points are badly worn, or pitted, unscrew the contact screws from their mounting brackets, and install new contact screws. At assembly there should be a space of 1/32-inch between the contact screw point and the follow-up

contact when one of the contact points is touching the contact arm. Adjust for this clearance by turning the contact screws

inward or outward until the desired clearance is obtained. Clean the slip rings with crocus paper.

5M15. Cleaning and repairing brushes. (See Figure 5-53.) The brushes on the brush block should be cleaned with crocus paper. The

5M16. Removing the differential and lead screw assemblies. (See Figures 5-59 and 5-60.) Since all mounting brackets on the forward face of the main mounting plate are doweled, it is necessary to raise all the brackets simultaneously to clear the dowel pins without distorting the connecting parts. Remove the follow-up contact assembly (see Section 5M11). Remove the slip ring and contact assembly (see Section 5M12). Remove the lead screw drive motor (see Section 5M4). Remove all the bracket mounting screws. Lift the jack

1. TAKE-UP SPRING
2. OIL WELL COVER AND SPRING SUPPORT
3. END PLATE
4. ROLLER SHAFT AND PINION
5. FRICTION ROLLER
6. LEAD SCREW YOKE
7. LIMIT SWITCH OPERATING SCREWS
8. ROLLER AND PIVOT
Figure 5-58. Lead screw yoke assembly removed.

5M17. Disassembly of the lead screw assembly. (See Figures 5-58 and 5-61.) Unscrew and remove the lead screw and follow-up pinion from the lead screw yoke. Remove the end plate retaining screws, end plate, thrust spring washer, and ball bearing from the upper end of yoke. Push the roller and pinion upward as shown in Figure 5-61, and remove them from the yoke. The ball bearing on the opposite end of the yoke is removed by removing the end plate and thrust spring washer.

5M18. Cleaning and repairing the lead screw assembly. Do not attempt to remove the friction roller from the roller shaft and pinion. Replace this assembly as a unit. Thoroughly clean all parts in Navy-approved cleaning fluid. Examine the friction roller and guide rod roller for flat spots. The diameter of the friction roller should be 1.2505 inches maximum and 1.2480 inches minimum. If the roller is smaller than 1.2480 inches, replace the complete roller shaft and pinion assembly.

5M19. Assembling the lead screw assembly. (See Figures 5-58 and 5-61.) Install the lower end plate on the yoke. Place the ball bearing in the yoke with the open face of the bearing upward. Place the friction roller shaft and the pinion assembly in position in the yoke. Install the upper ball bearing in the yoke with the open end of the bearing toward the roller shaft. Place the thrust spring washer on the bearing with the protruding section of the washer away from the bearing. Install the end plate and the end plate retaining screws.

1. END PLATE SCREW
2. END PLATE
3. THRUST SPRING WASHER
4. BALL BEARING
5. ROLLER SHAFT AND PINION
6. FRICTION ROLLER
7. LEAD SCREW YOKE
8. TAKE-UP SPRING
9. OIL WELL COVER AND SPRING SUPPORT
Figure 5-61. Roller shaft and pinion removed from yoke.

5M20. Disassembly of the differential assembly. (See Figures 5-60, 5-62, and 5-63.) Remove the four spur gear retaining screws, and the spur gear from the lower differential bevel gear. Remove the screw, retaining plate, bearing, and differential bevel pinion from the spider shaft. Support the differential bevel face gear which is mounted on the short differential shaft on bakelite or other soft blocks to protect the gear teeth. Do not use brass or steel blocks. Using a brass rod as shown in Figure 5-62, press out the shaft from the bearing. Remove the bearing from the gear. The bearings are a light press fit on the shaft, and a hand press fit in the gear housing. Remove the four screws that secure the differential end plate and gear hub to the upper differential bevel face gear, and lift off the plate and

5M21. Cleaning, inspection, and repair of the differential assembly. (See Figure 5-60.) Thoroughly clean all parts of the differential assembly with Navy-approved cleaning fluid. Dry all parts thoroughly. Replace all bent, broken, or heavily scored parts. If the differential shaft is lightly scored, remove the score marks with an oilstone, and polish with crocus paper. Visually inspect the bearings, and replace any cracked or otherwise damaged bearings. Remove light nicks from the gear

Figure 5-63. Pressing out long end of differential shaft.

teeth with a knife-edge file. Gears with cracked or chipped teeth should be replaced.

5M22. Installing the gear and bearing on the short end of the differential shaft. (See Figure 5-64.) Support the shoulder on the long end of the differential shaft in a special bed plate on an arbor press as shown in Figure 5-64. This is necessary in order to prevent bending the shaft. Place one of the differential bevel face gears over the short end of the shaft with the gear teeth facing the spider. Place one of the two identical ball bearin