0336789 JOHNSON CLAMP, Seal to carb. body

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.
This Program can only be administered after a failure occurs. The decision whether to apply the Program is made by the dealer. When reporting the repair, use "PS0904" as the Part Number and "7755" as the Group Number. Use "96" as the Warranty Claim Description Code and use "Z" as the SIMS Description Code.
This Revised Service Letter replaces the February 4, 1996 Service Letter. Changes have been made to the Problem, Affected Product, Parts Needed, Action Required, and Service Claim Allowances.
Termination Date
February 28, 1998Problem
Fuel injector tips may fail on certain 3176 and 3176B Truck Engines and Challenger 75 and 85 Tractors.
Affected Product
Model & Identification Number
3176 (7LG7500-Up)
3176B (9CK1-9353)
CH75C (4KK500-840)
CH85C (9TK1-1407)
Parts Needed
Reference the Rework Procedure to determine the quantity of parts to be replaced.
3176 (7LG) Parts
Up to 6 - 0R4523 Injector [7LG7500 - Up (325, 350 and 360 HP)]Up to 6 - 0R4525 Injector Gp [7LG7500 - Up (275 and 300 HP)]Up to 6 - 9X7317 Seal-O-Ring (injector tip o-ring)Up to 6 - 9X7557 Seal-O-Ring (injector upper o-ring)Up to 6 - 9X7722 Seal-O-Ring (injector lower o-ring) 3176B (9CK) Parts
Up to 6 - 0R4526 Injector Gp [9CK (275 HP)]Up to 6 - 0R4527 Injector Gp [9CK (300 and 325 HP)]Up to 6 - 0R4528 Injector Gp [9CK (342, 350, 365 and 335/365MT HP)]Up to 6 - 9X7317 Seal-O-Ring (injector tip o-ring)Up to 6 - 9X7557 Seal-O-Ring (injector upper o-ring)Up to 6 - 9X7722 Seal-O-Ring (injector lower o-ring) CH75C/85C (4KK and 9TK) Parts
Up to 6 - 0R4520 Injector GpUp to 6 - 9X7317 Seal-O-Ring (injector tip o-ring)Up to 6 - 9X7557 Seal-O-Ring (injector upper o-ring)Up to 6 - 9X7722 Seal-O-Ring (injector lower o-ring) Additional parts may be needed with contingent damage to engine such as cylinder head, cylinder pack, turbocharger, etc..
Action Required
1. Inspect the failed injector for a cracked or broken tip. If the tip is not cracked or broken, this program does not apply. Refer to the attached rework procedure.2. Replace the fuel injectors according to the attached rework procedure and repair any additional damage caused by the cracked tip.Service Claim Allowances (Truck Engines)
Service Claim Allowances (Tractors)
Parts Disposition
Handle the parts in accordance with your Warranty Bulletin on warranty parts handling.
Attach.(1-Rework Procedure)Rework Procedure
1. Remove the necessary air piping, air cleaners, valve covers, Jake Brakes, and rocker arm assemblies. Remove the lower plug at the rear of the fuel manifold and drain the fuel from the cylinder head and manifold. Reinstall the plug.2. Diagnose the problem to the specific injector. Inspect the failed injector for a cracked or broken tip. If the tip is not cracked or broken, this program does not apply.3. Determine if the other injectors should or should not be replaced. Remove the other injectors and check the date code stamped on the nozzle cone. 4. If a portion of the tip dropped into the cylinder during operation, remove the cylinder head. Otherwise, proceed to step 7.5. Inspect for damage to cylinder head, piston, liner, and turbocharger exhaust wheel fins.6. Replace those parts damaged by the tip failure. Refer to Special Instructions SEHS9540 "3176 Cylinder Head Gasket Repair Procedure", SEBF8262 "Reuse of Cylinder Heads on 3176 Engines with Injector Tip Damage", and Engine Service Manual. Proceed to step 9.7. Remove any excess fuel which may have drained into the cylinder.8. Ream the injector sleeve until the sleeve has been cut to provide a full length concentric taper past the 9X7317 tip seal/sleeve interface.9. Lubricate the two larger o-ring seals with engine oil and install injectors.Apply 6V4876 Molycote to the hold down bolt threads and tighten the bolts to a torque of 33 N m (24 ft. lb.). 10. Adjust the valves and injectors. Install the Jake Brakes if so equipped and adjust. Complete the assembly.11. Prime the fuel system as follows:a. Open the air bleed on the siphon block.b. Hand prime to remove air (until fuel is visible).c. Close air bleed.d. Hand prime until valve opens.Valve will "click" open.e. Tighten priming pump handle.12. Stamp the block with the letter "GS".