A New Exhaust Coupling With A Flow Conditioner Feature Needs To Be Installed On Certain 793 And 793B Trucks Caterpillar

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 "PS4651" 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

Exhaust swirl between the high pressure turbine outlet and the low pressure turbine inlet can cause high stress in the low pressure turbine blades. A new coupling with a flow conditioner feature will reduce the exhaust swirl and lower the stress in the low pressure turbine blades. The lower stress will increase the service life of the low pressure turbo.

Affected Product
Model & Identification Number

793 (3SJ1-99999)

793B (1HL1-99999)

Spare/Reman Engines

3516 MUI 54Z1-1193

3516 EUI 2PK1-1574

3516 REMAN MUI 6CL1-312

3516 REMAN EUI 7CL1-594

Parts Needed

12 - 5P7128 BOLT-WASHER

2 - 1596076 COUPLING-TUR

Action Required

See the attached procedure.

Service Claim Allowances

NOTE: This is a 4-hour job.

NOTE: Labor may be claimed if the repairs are made in chassis. Labor may also be claimed on a spare or reman engine in dealer stock. Labor may not be claimed if the update is installed during an overhaul.

NOTE: Use a 99Z code for spare components in the serial number field when claiming against a spare engine.

NOTE: 4 hours may be claimed for every turbine housing that must be removed, salvaged, and installed due to broken bolts.

Parts Disposition

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

Attach.

(1-Rework Procedure)

Rework Procedure

1. Remove the front and rear turbo steps.

2. Remove the two 7E-0087 exhaust couplings. See Illustration 1 and the steps below.

3. Generously use penetrating oil on the six inch 5P-7128 bolts that connect the exhaust coupling to the high pressure turbo. Carefully and slowly remove the six bolts.

4. If a bolt breaks off in the turbine housing, salvage the housing by drilling out the broken bolt. Extra labor is allowed to remove, salvage, and re-install the turbine housing.

5. Carefully remove the four inch 9X-8285 bolts at the low pressure turbine inlet. This hardware will be reused.

6. Remove the old 7E-0087 Exhaust Coupling and install a new 159-6076 Exhaust Coupling with the flow conditioner feature. Position the flow conditioner with the "up" arrow pointing up.

7. Install the six new 5P-7128 inch bolts with antiseize compound on the bolt threads and bottom of the bolt head surfaces. Tighten the six bolts to 47 ± 5 N·m.

8. Install the four previously removed inch bolts with antiseize compound on the bolt threads and bottom of the bolt head surfaces. Tighten the four bolts to 215 ± 40 N·M.

9. Retighten the inch bolts to 215 ± 40 N·m and retighten the inch bolts to 47 ± 5 N·m.

10. Repeat the process for both the front and rear low pressure turbos.

11. Install the front and rear turbo steps.

12. Start the engine and check for proper operation.