1998/01/26 Caterpillar

D9R (7TL, 8BL),
D10R (3KR) Track-Type Tractors;
24H (7KK) Motor Graders;
631E (1AB),
633E (2PS),
637E (1FB),
651E (4YR),
657E (5YR, 6PR, 6TR, 7KR) Wheel-Tractor Scrapers;
769D (5TR),
771D (6JR),
773D (7ER),
775D (6KR) Off-Highway Trucks;
834B (7BR) Wheel Tractors;
836 (7FR) Compactors;
988F (2ZR),
990 (4FR) Wheel Loaders;
5110 (7GN, 8HN) Excavators;
PM-565 (3TK) Cold Planers

Reference: Special Instruction, "Disassembly And Assembly Of the 144-0835 Unit Injector Hydraulic Pump Group", REHS0192-03.

The engines in these machine are equipped with Hydraulically Actuated Electronic Unit Injectors (HEUI). A part of the HEUI system is the unit injector hydraulic pump group. The new 154-6732 Pump Kit is available to recondition the 134-9405 and 144-0835 Unit Injector Hydraulic Pump Groups rather than replacing the complete pump. The 154-6732 Pump Kit includes:

* Rotating Group.

* Control Piston.

* Yoke.

* Drive Shaft.

* Seal Kit.

* Front Bearing.

* Housing Gasket.

* Special Instruction, "Disassembly And Assembly Of the 144-0835 Unit Injector Hydraulic Pump Group", REHS0192-03.

NOTE: The Special Instruction identifies seven tools that must be fabricated to facilitate the disassembly and assembly of the pump. Contact the Caterpillar Dealer for the dimensions and specifications for fabricating the tools. Fabricating these tools will take some time, so please consider this before the first reconditioning of a pump.

Some additional information and corrections for Special Instruction, "Disassembly And Assembly Of the 144-0835 Unit Injector Hydraulic Pump Group", REHS0192-03 follow:

* On Page 2, under Required Tools, add the following sentence:

Contact the Caterpillar Dealer for the dimensions and specifications that are needed to fabricate the tools.

* On Page 4, Remove Step 9.

* On Page 5, add the following information to the end of Step 14:

Visually inspect the 154-6735 Pintle Bearing (20). Replace the bearing with a new 154-6735 Pintle Bearing only if the bearing is defective.

* On Page 5, add the following information to the end of Step 15:

Visually inspect the 154-6735 Pintle Bearing. Replace the bearing with a new 154-6735 Pintle Bearing only if the bearing is defective.

* On Page 5, change Step 17 to read: Remove the spring seat (18) and spring.

* On Page 6, change the Note after Step 20 to read:

NOTE: Protect the face of the valve block by placing the face on a soft surface.

* On Page 6, add the following Note before Step 1:

NOTE: Thoroughly clean both the housing and the valve block before reassembling the unit injector pump.

* On Page 6, change Step 3 to read: Install the spring, the spring seat (18) and the yoke (22).

* On Page 8, change Step 9c to read: Once the rotating group is installed, turn the rotating group in order to ensure that the three pins (34) are still in the special notches. If the rotating group jams, the pins (34) need to reinserted into the proper position. The three pins in the rotating group are held in the special notches with a "C" clip retaining ring. The "C" clip applies force against the inside diameter of the rotating group's cylinder block in order to hold the pins in position. See Illustration 32.

* On Page 9, after Step 18, add the following Note:

NOTE: Step 19 through Step 21 defines the procedure for the installation of the shaft seal. These steps should be followed precisely. The shaft seal should be placed barely below the face of the housing. The snap ring should then be positioned against the seal. Both the snap ring and the seal should be driven into the bore together until the snap ring seats in the groove.

* On Page 9, change Step 23b to read: Tighten the bolts (2) to a torque of 16 ± 1 N·m (12.0 ± 0.5 lb ft).