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SERIES 50 WATER PUMP

The centrifugal-type water pump circulates the engine coolant through the cooling system. ‪

The pump is mounted on the rear of the gear case and is driven by the water pump drive gear. See Figure 20460 . The water pump drive gear meshes with the bull gear. ‪

Water Pump Mounting

An impeller is pressed on one end of the stainless steel drive shaft. The other end of this shaft has internal threads, and a retaining bolt secures the water pump drive gear to the shaft. Two tappered roller bearing assemblies are used to support the shaft. See Figure 20461 . ‪

1. Retaining Bolt ‪

11. Oil Seal ‪

2. Washer ‪

12. O-ring Seal ‪

3. Gear, Water Pump Drive ‪

13. Drain Cock ‪

4. Snap Ring ‪

14. Housing, Water Pump ‪

5. Bearing Race ‪

15. Pipe Plug, Water Pump Housing ‪

6. Roller Bearing, Small ‪

16. Water Seal ‪

7. Spacer Rings ‪

17. Impeller ‪

8. Roller Bearing, Large ‪

18. O-ring, Water Pump Cover ‪

9. Bearing Race ‪

19. Water Pump Cover ‪

10. Drive Shaft ‪

20. Snap Ring, Water Pump Cover ‪

Water Pump Details and Relative Location of Parts

An O-ring rubber ring, located in a groove in the water pump housing, seals the water pump to the gear case. An O-ring, located under the water pump cover, seals the cover to the water pump housing. The water pump bearings are lubricated by splash oil through a passage from the front of the pump housing. ‪

An oil seal is located behind the bearing assemblies, and a unitized, spring-loaded, face type water seal is used behind the impeller. This seal prevents water from leaking down the shaft and into the gear case. It also prevents lubricating oil from entering the cooling system. The water and oil seals cannot be replaced without removing the water pump from the engine. ‪

Repair or Replacement of Water Pump

To determine if repair or replacement is necessary, perform the following procedure. See Figure 21996 . ‪

Flowchart for Repair or Replacement of Water Pump

Draining and Removal of Water Pump

Drain the cooling system before removal of the water pump as follows: ‪

  1. Open the drain cocks located at the right rear corner of the engine at the bottom of the water pump and in the thermostat housing.

Remove the water pump as follows: ‪

  1. Loosen the hose clamps and remove the coolant hoses from the water pump housing.
  2. Loosen and remove the three water pump housing-to-gear case bolts. Remove the water pump from the engine by pulling it straight out of the gear case.

Disassembly of Water Pump

Disassemble the water pump as follows: ‪

EYE INJURY

To avoid injury from flying debris, wear a face shield or goggles.

  1. Remove water pump cover snap ring with snap ring pliers, J 28507 or equivalent. Remove water pump cover and seal ring.

    NOTICE:

    When clamping gears, use soft jaws on vise to prevent damage to the gear teeth. ‪

  2. Clamp the water pump drive gear in a vise, with the impeller facing up. Use a two-screw gear puller and remove the water pump impeller from the shaft, using the two threaded holes in the impeller.
  3. Hold square end of water pump shaft and remove water pump drive gear retaining bolt and washer. See Figure 20594 .

    Water Pump Drive Gear Retaining Bolt Removal

  4. Use a two-jaw gear puller to remove the water pump drive gear from the drive shaft.

    Note: The water pump drive gear may be a slip fit on the drive shaft because of manufacturing tolerances.

  5. Remove the snap ring from the water pump housing. See Figure 20463 .

    Snap Ring Removal

  6. Support the water pump housing, engine side down, using steel blocks or plates, to allow at least 76 mm (3 in.) of clearance between the pump housing and the press bed.
  7. Press the drive shaft and bearings assembly out through the front (engine side) of the water pump housing, until both bearing races are clear of the housing.

    Note: Once the bearing assemblies are pressed out of the water pump housing, they must be replaced with new assemblies.

    NOTICE:

    Do not allow brass drift to score housing bore when tapping out seals. A scored bore will cause coolant leaks and can damage engine. ‪

    CHEMICAL BURNS

    To avoid injury from chemical burns, wear a face shield and neoprene or PVC gloves when handling fluoroelastomer O-rings or seals that have been degraded by excessive heat. Discard gloves after handling degraded fluoroelastomer parts.

  8. Remove both the water and oil seals from the housing using a brass drift and hammer.
  9. Support the drive shaft assembly on two steel blocks, at the bearing inner race.
  10. Insert extension tool, J 35988-3A, part of tool set J 35988-B , in end of drive shaft. See Figure 20464 .

    Removing Bearing Assemblies

  11. Press the drive shaft out until it is clear of both bearing and race assemblies. Discard the used bearings, races and the two spacer rings located between the bearing packs.
Inspection of Water Pump

Inspect the water pump parts as follows: ‪

  1. Wash all of the pump parts in clean fuel oil.

    EYE INJURY

    To avoid injury from flying debris when using compressed air, wear adequate eye protection (face shield or safety goggles) and do not exceed 40 psi (276 kPa) air pressure.

  2. Dry the parts with compressed air.
  3. Visually inspect the water pump housing, cover O-rings and all other water pump parts for cracks, wear or other damage.
    1. Replace damaged or worn parts.
    2. Reuse remaining components.
  4. Replace the twin bearing assemblies, the oil seal and water seal.

Assembly of Water Pump

Assemble the water pump as follows: ‪

  1. Coat the bearing bores of the water pump housing and the drive shaft bearing surfaces with clean engine oil.

    NOTICE:

    Although the bearings are identical, the bearings and races are matched parts, and should be installed as they are removed from the box. Parts that are not matched will cause damage to the water pump. ‪

  2. Assemble the new bearing packs, as follows:
    1. Place the small spacer ring on the inner bearing race. See Figure 20465 .
    2. Place the larger spacer ring on the outer bearing race.
    3. Bearing Pack Assembly

  3. Using the drive shaft support tool, J 35988-18 part of J 35998B and the water pump fixture J 35988-2 part of J 35998B , parts of tool set J 35988-B . Install the support tool into the center of the fixture. See Figure 20466 .

    Bearing Installation Set-Up

  4. Install the extension tool, J 35988-3A part of tool set J 35988-B , on the end of the water pump shaft. Install the assembled bearing packs to the drive shaft. See Figure 20467 .

    Bearing Placement

  5. Center the small end of tool J 35988-1 part of J 35998B , part of tool set J 35988-B , on the bearing inner race. See Figure 20468 . Press the bearing pack onto the shaft until it contacts the shoulder of the shaft. Remove the tool used to pilot the bearings.

    Bearing Installation

  6. Remove the shaft and bearing assembly from the press.
Test Bearing Assembly

Check bearing assembly as follows: ‪

  1. Turn bearings to ensure they turn freely.
  2. If bearings bind, disassemble water pump and replace bearing assembly. Refer to Section .

Assembly of Water Pump - cont'd

Continue assembling the water pump, as follows: ‪

  1. Coat the oil seal contact area of the water pump housing with a thin film of clean engine oil. See Figure 20469 .

    Oil Seal Contact Area Lubrication

  2. Install a new oil seal into the water pump housing from the front (gear side). See Figure 20470 .

    Oil Seal Positioning

    NOTICE:

    The contact surface of the oil seal is coated with a special sealant. Do NOT remove this sealant before installing the oil seal. If sealant is removed, leakage can occur. ‪

  3. Place the small end of tool J 35988-1 part of J 35998B , part of tool set J 35988-B , into the water pump housing until it contacts the oil seal. See Figure 20471 .

    Oil Seal Installation

  4. Press the oil seal into the housing until the seal lip is bottomed in the pump housing. Remove the tool J 35988-1 part of J 35998B , part of tool set J 35988-B .
  5. Coat the bearings with clean engine oil.
  6. Place the water pump housing, with the gear side up, on a press bed.
  7. Install the drive shaft, with bearings installed, to the water pump housing. See Figure 20472 .

    Note: During the bearing installation, the water pump housing must be parallel to the press bed or table surface.

    Drive Shaft Insertion

    NOTICE:

    The drive shaft must be installed using the outer bearing race only. Any other attempt at installation may damage the bearings. ‪

  8. Place the large end of tool J 35988-1 part of J 35998B , part of tool set J 35988-B , over the drive shaft so that the lip of the tool rests squarely on the outer bearing race. See Figure 20473 .

    Drive Shaft Installation

  9. Press the drive shaft and bearing assembly into the water pump housing, using tool J 35988-1 part of J 35998B , part of tool set J 35988-B , until it is seated firmly against the shoulder in the housing.
  10. Install the snap ring to the water pump housing. See Figure 20474 .

    Snap Ring Installation

    NOTICE:

    Current water pump seals have a green sealant applied by the manufacturer, Do not apply additional sealant to the outside of the seal case or to the seal contact area on the pump housing. Excess sealant in these areas may result in failure of the seal to seat properly in the bore, causing shortened seal life or leakage. ‪

  11. Turn the water pump housing over and check to make sure no residual sealant remains in the water seal bore or on the seal flange contact surface. See Figure 20475 . Remove any residual sealant found in these areas.

    1. Seal Bore ‪

    2. Water Pump Housing ‪

    Water Pump Housing Seal Bore

    NOTICE:

    The extension must contact and support the shaft when installing the water seal and impeller to prevent damage to the bearings. ‪

  12. Install the extension J 35988-3A part of J 35998B , part of tool set J 35988-B , to the fixture tool. See Figure 20476 .

    Support Installation

  13. Install the water pump housing assembly to the fixture. See Figure 20477 .

    Water Pump Impeller Installation Set-up

  14. Turn the adjustor wheel to raise the extension until it contacts the drive shaft in the water pump housing.
  15. Apply Loctite primer (Locquic Primer N, Part No. 764) by swabbing onto the I.D. of the rotor of the seal.
  16. Install a new water seal over the drive shaft and seat it in the water pump housing. See Figure 20478 .

    Water Seal Insertion

  17. Detroit Diesel has released a new water pump coolant seal and oil seal. The new coolant seal requires the use of new seal installer J 3598819 , part of tool set J 35988D . The new seals went into effect with engine serial number 4R38836. The use of Loctite 290 is not required with the new coolant seal. ‪

  18. Position seal installer J 3598819 , part of tool set J 35988-D over the water seal. See Figure 42249 .

    Water Seal Installation

  19. Press the water seal into the housing until the flange of the seal case contacts the water pump housing a full 360. Remove tool J 3598819 , part of tool set J 35988-D .
  20. With the water pump housing still housed in tool J 35988-2 , part of tool set J 35988-B , and located on a press bed, position the impeller over the square end of the drive shaft with the vanes of the impeller facing down. See Figure 20481 .

    Water Pump Impeller Installation

    NOTICE:

    During this procedure, the drive shaft must be supported by the extension tool J 35988-3A, part of tool set J 35988-B . Failure to support the drive shaft while installing the impeller may result in bearing damage. ‪

  21. Using the impeller installation tool J 35988-14 part of J 35998B , part of tool set J 35988-B , press the impeller on until the tool is flush against the water pump body. See Figure 20482 .

    Water Pump Impeller Location

  22. Turn the housing over and place it face (impeller side) down on the fixture J 35988-2 part of J 35998B , part of tool set J 35988-B . See Figure 20483 .

    Water Pump Drive Gear Installation

  23. Install the water pump drive gear to the drive shaft.

    Note: The water pump drive gear may have a slip fit. This is due to manufacturing tolerances and is acceptable.

    NOTICE:

    If the gear has a press fit, turn the adjustor wheel to raise the extension J 35988-3A, part of tool set J 35988-B , until it contacts and supports the shaft. This is necessary to prevent damage to the bearings when pressing the gear onto the shaft. ‪

  24. Using the small end of tool J 35988-1 part of J 35998B , part of tool set J 35988-B , press the drive gear down onto the drive shaft until it touches the bearings. See Figure 20484 .

    Water Pump Drive Gear Installation

  25. Install the retaining bolt and washer. Hold the square end of the drive shaft and torque the retaining bolt to 102-126 Nm (75-93 lbft).
Assembly Integrity Test

Verify the assembly integrity as follows: ‪

  1. Turn the pump over and install the water pump impeller slip and lash tester, J 35687 , into the tapped holes provided in the impeller.

    NOTICE:

    When clamping gears, use soft jaws on vise to prevent damage to the gear teeth. ‪

  2. Clamp the water pump drive gear in a vise, with the impeller facing up.
  3. Using a 1/2 in. drive torque wrench in the hole provided in the center of the slip and lash tester, J 35687 , apply 68 Nm (50 lbft) torque in either direction.
    1. The impeller must withstand 68 Nm (50 lbft) torque without slipping.
    2. If the torque specification is not satisfied, disassemble water pump and replace the impeller. Refer to Section .
  4. Using a dial indicator with magnetic base, measure the total runout of the water pump drive gear at four places, at 90 intervals. Maximum allowable runout is 0.0635 mm (0.0025 in.). See Figure 20485 .

    Measuring Water Pump Drive Gear Runout (GCM)

    1. If this value is exceeded, disassemble the water pump and check for burrs or foreign particles. Refer to Section .
    2. If runout still exceeds limits, disassemble water pump and replace the drive gear or drive shaft as necessary. Refer to Section .
  5. Remove dial indicator and magnetic base.

Assembly of Water Pump (Continued)

Continue assembly of the water pump as follows: ‪

EYE INJURY

To avoid injury from flying debris, wear a face shield or goggles.

  1. Install seal ring, water pump cover, and snap ring with the beveled side of snap ring facing out. Tap around the inside rim of the snap ring with a brass drift and hammer to seat snap ring in groove fully.

Installation of Water Pump

Install the water pump as follows: ‪

  1. Coat the water pump seal ring with clean engine oil.
  2. Install the seal ring to the groove in the water pump housing.
  3. Coat the water pump drive gear with clean engine oil.
  4. Install the water pump to the engine, meshing the water pump drive gear with the bull gear.
  5. Install the three water pump housing-to-gear case bolts. Tighten the bolts alternately and evenly to draw the water pump straight into the engine. Torque the bolts to 58-73 Nm (43-54 lbft).
  6. Measure the gear backlash. Refer to Section .
  7. Slide the coolant hoses into position and tighten the hose clamps.
  8. Refer to Section for verification of proper water pump installation.