Product Support Program For Repairing Fuel Injectors And Replacing Rocker Arms On Certain Challenger 75 Tractors Caterpillar

NOTE: The information supplied in this service letter may not be valid after the termination date of this program. Do not perform the work outlined in this Service Letter after the termination date without first contacting your Caterpillar product analyst.

NOTE: This Program can be administered either before or after a failure. In either case the decision whether to apply the Program is made by the dealer. When reporting the repair, use "PS4729" as the Part Number and "7755" as the Group Number. If administered before failure, use "56" as the Warranty Claim Description Code and use "T" as the SIMS Description Code. If administered after failure, use "96" as the Warranty Claim Description Code and use "Z" as the SIMS Description Code.

Termination Date

Problem

The retainer clips for the fuel injectors may crack or break on certain Challenger 75 Tractors. Also, the unit injector rocker arms may crack.

Affected Product
Mode & Identification Number

CH75 (4CJ1-308, 4CJ311-317, 4CJ320-331, 4CJ350, 4CJ356,4CJ375-378, 4CJ380, 4CJ382, 4CJ383, 4CJ386, 4CJ391, 4CJ394, 4CJ396, 4CJ406)

Parts Needed

6 - 7E8872 Rocker Arm Assembly (Use as needed)

6 - 6I2538 Clip

6 - 0R3398 Injector Group (Use as needed)

Action Required

See attached rework procedure.

Service Claim Allowances

If required, add the following:

0.5 Hr R&I first fuel injector

0.4 Hr R&I each additional fuel injector

Parts Disposition

Handle the parts in accordance with your Warranty Bulletin on warranty parts handling.

Attach.

(1-Rework Procedure)

Rework Procedure

1. Check for 3X stamped on the block next to the serial number plate. If the block has been stamped do not proceed with the rework unless suspect injectors have recently been installed in that engine. Check SIMS history to be sure.

2. Remove hood from over engine, valve covers, and rocker arm stands.

3. Inspect the injector rocker arms for the heat code and die code as shown in Illustration 1. Replace any injector rocker arms that have both heat code "1" and die code "1*C" (* Note symbol in Illustration.)

Illustration 1 - Injector Rocker Arm Identification

NOTE: Injector rocker arms must have BOTH heat code "1" and die code "1*C" to be eligible for replacement.

4. Inspect unit injectors for a paint strip across the top face of the spring retainer (either yellow or red). A paint stripe indicates the unit injector has been reworked previously.

5. Remove the return to tank fuel line at the fuel manifold adapter (siphon break) and install a 0-100 psi gauge at the manifold.

6. Use an O-ring pick to remove the O-ring from the spring retainer of each injector to be reworked. Remove the rocker arm thrust pad from each injector.

7. Pressurize fuel system using the priming pump to 30 psi and maintain pressure from 15-30 psi during rework (fuel pressure keeps the injector plunger extended during clip replacement).

8. Inspect the 9U5300 Unit Injector Spring Compressor Group. See Illustration 2. The 9U5320 Fixture is for off engine use only.

Illustration 2 - 9U5300 Unit Injector Spring Compressor Group

Install the compressor group into a rocker arm support bolt hole with the arm aligned over a unit injector spring. Be sure the 5P0541 Nut is backed off to the top of the 9U5321 Tube before tightening the 7X0909 Bolt.

NOTE: Install the compressor at hole locations closest to the inlet valves.

Tighten the 5P0541 Nut to compress the injector spring only enough to allow removal of the clip (the clip is like a valve keeper).

9. Use a small magnet (pencil size works best) and a suitable clip removal tool to remove the old clip from the injector.

NOTE: Do not release tension on the spring until a new clip is installed. Releasing tension before a new clip is installed will cause the injector will come apart. See Illustration 3.

Illustration 3 - Use caution when handling injectors with missing clips. Loose springs and retainers will allow ball to come loose and fall into the engine.

10. Inspect the clip that was removed. If the clip is broken in more than three (3) pieces (or if you suspect small pieces have fallen into the injector) the unit injector must be replaced.

11. Install a new 6I2538 Clip and remove the spring compressor group.

12. Replace the thrust pad and the thrust pad retaining O-ring.

NOTE: If the thrust pad retaining O-ring is damaged install a new 336044 O-Ring Seal

13. Mark across the top face of the spring retainer with a yellow strip and proceed with rework to the remaining injectors.

14. After completion of the rework, stamp "3X" on the cylinder block near the Serial Number Plate.