Section 2.8
Fuel Pump With One-Piece Drive Shaft and Hub Assembly

An improved fuel pump replaced the former fuel pump, effective with July 1995 engine production. The improved and former pumps are similar, except that the improved pump has a one-piece drive shaft and hub assembly. See Figure "Current Compressor-Mounted Fuel Pump Assembly with One-Piece Drive Shaft and Hub Assembly" .

Figure 1. Current Compressor-Mounted Fuel Pump Assembly with One-Piece Drive Shaft and Hub Assembly

Figure 2. Current Gear Case-Mounted Fuel Pump Assembly

The current fuel pump system consists of the following components:‪

• Barnes positive displacement type fuel pump with one-piece drive shaft and hub assembly
• Gear train mounting adaptor

  Note: Effective with engine serial number 06R0549855 built on October 19, 1999, gear case-mounted fuel pumps have a splined drive shaft and splined gear coupling assembly. See Figure "Current Gear Case-Mounted Fuel Pump Assembly" . The former and current fuel pump and fuel pump drive assemblies are not interchangeable. Both current assemblies must be used together. Components of former and current pump assemblies and drive assemblies are not interchangeable.

  See Figure "Gear Case and Air Compressor-Mounted Fuel Pumps" for the current positive displacement gear-type fuel pump is shown in the next illustration. ‪

  

  1. Gear Case-Mounted Fuel Pump Assembly‪	5. Air Compressor-Mounted Fuel Pump‪
  2. Gear Case Housing‪	6. Air Compressor Assembly‪
  3. Fuel Pump Drive Adaptor‪	7. Brass Fittings‪
  4. Brass Fittings‪	‪

  Figure 3. Gear Case and Air Compressor-Mounted Fuel Pumps

The fuel pump transfers fuel from the supply tank to the fuel injectors. The pump circulates an excess supply of fuel through the injectors, which purges the air from the system and cools the injectors. The unused portion of fuel returns to the fuel tank by means of a fuel return line.‪

The fuel pump is either attached to a drive assembly mounted on the rear side of the gear case, or driven off of the rear of the air compressor. See Figure "Gear Case and Air Compressor-Mounted Fuel Pumps" .‪

The fuel pump cover and body are positioned by two dowels. The dowels aid in maintaining alignment between the body, cover and shafts. The mating surfaces of the pump body and cover are perfectly flat ground surfaces. A gasket is used between the cover and body.‪

The fuel pump body is recessed to provide running space for the pump gears. Recesses are also provided at the inlet and outlet positions of the gears. The small relief valve vent (5) (see Figure "Fuel Pump" ) permits the fuel oil in the inlet side of the pump to lubricate the relief valve at its outer end. This eliminates the possibility of a hydrostatic lock which would render the relief valve inoperative. Pressurized fuel contacts the relief valve through the passage to the head of the relief valve (1) and provides for relief of excess discharge pressures. Fuel re-enters the inlet side of the pump through the passage to the head of the relief valve (6) when the discharge pressure is great enough to move the relief valve back from its seat. Part of the relief valve may be seen through the passage to the head of the relief valve (6). The gear teeth vent cavity (7) provides escape for the fuel oil that is squeezed out of the gear teeth as they mesh together on the discharge side of the pump. Otherwise, fuel trapped at the root of the teeth would tend to force the gears apart, resulting in undue wear on the gears, shafts, body, and cover. See Figure "Fuel Pump" .‪

Figure 4. Fuel Pump

Two oil seals are pressed into the bore in the flanged side of the pump body to retain the fuel oil in the pump and the lubricating oil in the fuel pump drive and gear case. The oil seal vent (4) (see Figure "Fuel Pump" ) serves as a vent passageway in the body, between the inner oil seal and the suction side of the pump, which prevents building up any fuel oil pressure around the shaft ahead of the inner seal. The oil seals are installed with the lips of the seals facing each other. See Figure "Fuel Pump Oil Seal Arrangement" .‪

Figure 5. Fuel Pump Oil Seal Arrangement

Some fuel oil seepage by the fuel pump can be expected with a running engine and immediately after an engine has been shut down. This is especially true with a new fuel pump, new pump seals, or both, as the seals have not yet conformed to the pump drive shaft. Fuel pump seals will always allow some seepage. A drain hole in the pump body is provided to prevent fuel oil from being retained between the seals. Excessive fuel retention between the seals could provide enough pressure to cause engine oil dilution by fuel; therefore, drainage of the excess fuel oil is mandatory. However, if leakage exceeds one drop per minute, replace the pump. The drain hole should be checked for plugging at normal scheduled maintenance.‪

A spring-loaded relief valve incorporated in the pump body normally remains in the closed position, operating only when pressure on the outlet side (to the fuel filter) reaches approximately 448 kPa (65 psi).‪

In operation, fuel enters the pump on the suction side and fills the space between the gear teeth that are exposed at that instant. The gear teeth then carry fuel oil to the discharge side of the pump and as the gear teeth mesh in the center of the pump, the fuel is forced out the outlet cavity. Since this is a continuous cycle and fuel is continually being forced into the outlet cavity, the fuel flows from the outlet cavity into the fuel lines and through the engine fuel system under pressure.‪

The pressure relief valve relieves the discharge pressure by bypassing the fuel from the outlet side of the pump to the inlet side when the discharge pressure reaches approximately 448 to 517 kPa (65 to 75 psi).‪

The fuel pump should maintain the fuel pressure as listed in Table "Series 60 Engine Fuel System Parameters" .‪

Section 2.8.1
Repair or Replacement of Fuel Pump

To determine if repair or replacement of the fuel pump is necessary. See Figure "Flowchart for Repair or Replacement of Fuel Pump" .‪

Figure 6. Flowchart for Repair or Replacement of Fuel Pump

Section 2.8.2
Removal of Fuel Pump (One-piece Drive Shaft)

Perform the following steps for fuel pump removal:‪

1. Disconnect the fuel lines from the inlet and outlet openings of the fuel pump.
2. Remove the three fuel pump attaching bolts and withdraw the pump from the mounting adaptor on the gear case or air compressor.
3. Check the drive coupling and, if broken or worn, replace it with a new coupling.

Section 2.8.3
Disassembly of Fuel Pump (One-piece Drive Shaft)

Perform the following steps for fuel pump disassembly:‪

1. With the fuel pump removed from the engine, clamp the pump in a bench vise equipped with soft jaws.
2. Remove fuel inlet and outlet fittings from fuel pump cover.
3. Remove the pump from the vise and position pump on holding fixture (J–38767–1) hub side down. See Figure "Fuel Pump Holding Fixture" . Clamp the holding fixture in the vise.
   

   Figure 7. Fuel Pump Holding Fixture

4. Using a No. E-8 torx socket (J–25359–11, part of tool set J–25359–C)) , remove eight (8) bolts securing the pump cover to body.

   Note: Note the color of the foil gasket, gold or silver. If the pump is reassembled, the same color foil gasket must be used. The gaskets are of different thickness and establish correct internal clearance.

5. Separate the pump cover from the body by lifting it off the shafts and dowels. Remove and discard the foil gasket between the cover and body.

   Note: When the drive shaft is removed from the pump, the oil seals must be replaced.

6. Withdraw the driven shaft and gear and the drive shaft and gear assemblies from the pump body.
7. Remove the C-clips, and key from the drive shaft. Remove the C-clips and pin from the driven shaft.
8. Remove the gears from the shafts.

   Note: When the drive shaft is removed, the drive shaft needle bearing assembly in the pump body must also be removed to allow installation of the oil seal protector used during reassembly.

9. Use needle bearing remover (J–33853) with slide hammer and remove the needle bearing assemblies from the pump body and cover. See Figure "Needle Bearing Assembly Removal" .
   

   Figure 8. Needle Bearing Assembly Removal

10. Position pump on fixture (J–38767–1) and insert the lip of seal remover (J–1508–13) between the inner and outer oil seals. Tap the tool with a light hammer to drive the outer seal out of the pump body. See Figure "Oil Seal Removal" . Discard the outer seal.
    

    Figure 9. Oil Seal Removal

11. Repeat the process, removing the inner seal by placing the tool lip against the inside of the seal case. Discard the inner seal.
12. Unscrew and remove the relief valve cover and remove the relief valve plunger, spring and pin from the bore.
13. Remove the spacer from the relief valve cover.
14. Remove and discard the O-ring seal under the head of the cover.

Section 2.8.3.1
Cleaning and Inspection of Fuel Pump (One-piece Drive Shaft)

Perform the following steps to clean and inspect the fuel pump parts:‪

1. Clean all parts with clean fuel oil before inspection.

   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 276 kPa (40 psi) air pressure.‪

2. Dry the parts with compressed air.
3. Visually inspect the drive coupling for wear or damage.
   1. If wear or damage is found, replace the drive coupling.
   2. If no wear or damage is found, reuse the drive coupling.

   Note: Oil seals, once removed, must be discarded and replaced with new seals. Oil seals must be removed whenever the fuel pump drive shaft is withdrawn.

4. Visually inspect the drive shaft and hub assembly and idler gear shaft for scoring or wear.
   1. If scoring or wear is found, replace the drive shaft and hub assembly and idler gear shaft.
   2. If no scoring or wear is found, reuse the drive shaft and hub assembly and idler gear shafts.
5. Visually check the gear teeth for scoring, chipping or wear.
   1. If gear teeth are scored, chipped or worn, replace the parts as necessary.
   2. If gear teeth are not scored, chipped or worn, reuse the parts.
6. Visually inspect the relief valve. The valve must be free of score marks and burrs.
   1. If the relief valve is scored and cannot be cleaned up with fine emery cloth, replace the relief valve.
   2. If the relief valve is not damaged, reuse the part.

Section 2.8.4
Assembly of Fuel Pump (One-piece Drive Shaft)

Perform the following steps for fuel pump assembly:‪

1. Lubricate the lips of a new inner oil seal and pilot of oil seal installer (J–1508–8) with a light film of clean engine oil.
2. Place the oil seal adaptor (J–34158) on the pilot (J–1508–8) with the wide end of the adaptor against the handle.
3. Place inner oil seal on the pilot (J–1508–8) with seal case against the adaptor.
4. Support the pump body on wood blocks, hub side up, and insert the pilot into the shaft bore positioning the seal on the bore. Use a light hammer and drive the inner seal into the bore until the adaptor is bottomed against the pump body. See Figure "Installing Inner Oil Seal" .
   

   Figure 10. Installing Inner Oil Seal

5. Remove the installer (J–1508–8) and pilot (J–34158) and place the narrow end against the installer handle. See Figure "Installing Outer Oil Seal" .
   

   Figure 11. Installing Outer Oil Seal

6. Place a new outer seal on J–1508–8 with J–34158 faced away from the adaptor.
7. Carefully reinsert the installer pilot (J–1508–8 ) through the inner seal and position the outer seal on the bore. Use a light hammer and drive the seal into the bore until the adaptor is bottomed against the pump body.
8. Install seal protector (J–33021–A) on drive shaft and hub assembly and install through seal. Remove seal protector. See Figure "Seal Protector Installation" .
   

   Figure 12. Seal Protector Installation

   Note: The bearing numbers should always be against the tool during installation.

9. Install drive shaft needle bearings, using J–38767–8 (part of tool set J–38767–A) . The new tool permits bearing installation over drive shaft. Tool J–33854 can and should be used to install the other three bearings as shown. See Figure "Drive Shaft Bearing Installation" (this tool will support the bearing cages).
   

   Figure 13. Drive Shaft Bearing Installation

10. Install C-clip, key, gear, the final C-clip on drive shaft.

    Note: Hold the shaft in position with the gear against the pump body while handling to ensure the drive hub C-clip grooves do not contact the oil seals.

11. Position the pump body on the holding fixture (J–38767–1) hub side down.

    Note: When assembling pump, always use the same color foil gasket that was originally installed. Required gaskets for gear driven pump are listed in Table "Gasket Color vs. Gear Cavity Depth Chart (Gear Driven Pumps)" . Required gaskets for air compressor-driven pumps are listed in Table "Gasket Color vs. Gear Cavity Depth Chart (Air Compressor-Driven Pumps)" . If the color is unknown, measure the depth of the gear cavity in the pump cover and install the required gasket.

    Gear Cavity Depth ‪	Color Gasket Used ‪
    6.320-6.325 mm (0.24885 - 0.24905 in.)‪	Blue‪
    6.326-6.331 mm (0.24906 - 0.24925 in.)‪	Amber‪
    6.333-6.338 mm (0.24935 - 0.24955 in.)‪	Gold‪
    6.339-6.344 mm (0.24956 - 0.24975 in.)‪	Silver‪

    Table 7. Gasket Color vs. Gear Cavity Depth Chart (Gear Driven Pumps)

    Gear Cavity Depth ‪	Color Gasket Used ‪
    9.495-9.500 mm (0.37385-0.37405 in.)‪	Blue‪
    9.501-9.505 mm (0.37406-0.37425 in.)‪	Amber‪
    9.508-9.513 mm (0.37435-0.37455 in.)‪	Gold‪
    9.514-9.518 mm (0.37456-0.37475 in.)‪	Silver‪

    Table 8. Gasket Color vs. Gear Cavity Depth Chart (Air Compressor-Driven Pumps)
12. Place a new foil gasket on the face of the pump. With a finger tip, carefully smooth the gasket against the face to ensure there are no wrinkles, creases, or bubbles.
    1. If wrinkles, creases, or bubbles are present, and they cannot be removed with the finger, remove the gasket and repeat the procedure.
13. Assemble the driven gear shaft assembly by installing the C-clip on the shaft, and then installing the square-headed location pin in the hole in the shaft. Next, slide the driven gear on the shaft, aligning the pin on the shaft with the slot in the gear. Finally, install the C-clip on the shaft to hold the gear in place.
14. Carefully insert the driven shaft and gear assembly in the needle bearing in the pump body.

    Note: When positioning the cover, the fuel inlet (stamped on cover) must be on the same side as the relief valve bore in the pump body.

15. Position the needle bearing assemblies in the pump cover on the ends of the driven and drive shafts and slide the cover against the pump body.
16. Install eight cover retaining bolts. Use No. E-8 torx socket (J–25359–11, part of tool set J–25359–C) and torque bolts to 12-15 N·m (9-11 lb·ft).

    Note: As the outside of the pump body and cover are not machined and to prevent possible distortion, ensure that only the pump cover is gripped and that the vise jaws do not contact both body and cover.

17. Clamp the fuel pump cover in a soft-jawed vise with the relief valve bore in the pump body facing up.
18. Lubricate the relief plunger with clean engine oil and insert the plunger into the bore with the hollow end up. Insert the relief spring inside the plunger and the pin inside the spring.
19. Install the spacer in the bottom of the spring seat in the plug and install a new O-ring seal under the head of the plug. Thread the plug into the pump body and torque to 8-14 N·m (6-10 lb·ft).
20. Place the pump assembly on a bench, hub side up. Install the coupling onto the hub.
21. Install fuel inlet and outlet fittings in the pump cover.

Section 2.8.5
Installation of Gear Train-Driven Fuel Pump (One-piece Drive Shaft)

Install the fuel pump as follows:‪

Note: Effective with engine serial number 06R0549855 built on October 19, 1999, gear case-mounted fuel pumps have a splined drive shaft and splined gear coupling assembly. See Figure "Current Gear Case-Mounted Fuel Pump Assembly" . The former and current fuel pump and fuel pump drive assemblies are not interchangeable. Both current assemblies must be used together. Components of former and current pump assemblies and drive assemblies are not interchangeable.

1. Using a new O-ring seal, install the drive assembly on the gear case.
2. Install the fuel pump drive bolts and torque to 30-34 N·m (22-25 lb·ft) using the torque pattern shown. See Figure "Fuel Pump Drive Retaining Bolt Torque Sequence" .
   

   Figure 14. Fuel Pump Drive Retaining Bolt Torque Sequence

3. Using a new gasket, install the fuel pump and torque bolts to 30-38 N·m (22-28 lb·ft).
4. Install any other components that were removed for this procedure.

   PERSONAL INJURY ‪
   To avoid injury before starting and running the engine, ensure the vehicle is parked on a level surface, parking brake is set, and the wheels are blocked.‪

   PERSONAL INJURY ‪
   Diesel engine exhaust and some of its constituents are known to the State of California to cause cancer, birth defects, and other reproductive harm.‪ Always start and operate an engine in a well ventilated area. If operating an engine in an enclosed area, vent the exhaust to the outside. Do not modify or tamper with the exhaust system or emission control system.

5. Reconnect fuel inlet and outlet hoses, prime the fuel system, start the engine, and check for leaks.
6. Shut down engine upon completion.

Section 2.8.6
Installation of Air Compressor-Driven Fuel Pump (One-piece Drive Shaft)

Perform the following steps for air compressor-driven fuel pump installation:‪

Note: New fittings have sealant already applied. If reusing fittings, coat the threads lightly with Loctite® Pipe Sealant, PT-7260 , or equivalent before installing. To prevent sealant from entering fuel system, do not apply it to the first two (2) threads of the fitting. Do not use teflon tape or paste on the fittings.

1. If removed, install inlet and outlet fittings in the rear cover of the fuel pump.
2. Install drive coupling in drive hub of the fuel pump and affix a new gasket to the mounting flange of the pump.

   Note: When correctly positioned, the outlet fitting on the pump should be in approximately the 8 o'clock position when viewed from the rear, and the drain opening in the pump body facing down.

3. Index the drive coupling with the drive hub on the end of the air compressor crankshaft and align the pump mounting bolt holes with those in the air compressor rear cover.
4. Seat the fuel pump squarely against the air compressor. Install three (3) fuel pump mounting bolts and torque them to 30-38 N·m (22-28 lb·ft).
5. Connect the fuel inlet and outlet lines to the fuel pump and tighten.
6. Prime the fuel system before starting engine.
7. Refer to "2.8.5 Installation of Gear Train-Driven Fuel Pump (One-piece Drive Shaft)" for the exhaust caution before proceeding. Start and run the engine. Visually observe fuel pump for any leaks. Repair as necessary.
8. Shut down engine upon completion of test.