High-Pressure Fuel Line Leaks on Certain Tier 4 Engines {1250, 1252} Caterpillar

Engine

3512E (S/N: BZ3112-UP; SK3135-UP; SK5128-UP)

C175-16 (S/N: 3B9102-UP)

C175-20 (S/N: R4F129-UP)

Off-Highway Truck/Tractor

793F (S/N: D3T142-UP)

797F (S/N: LTZ140-UP)

Pumper

SPF743 (S/N: SK71-UP)

Introduction

The problem that is identified below does not have a known permanent solution. Until a permanent solution is known, use the solution that is identified below.

Problem

The fuel system leaks through the outer wall due to incorrect tolerance within the accumulator.

Solution

Caterpillar^® is aware of this problem, but a permanent repair has not been identified. As an interim solution follow the rework procedure given below.

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Do not operate or work on this product unless you have read and understood the instruction and warnings in the relevant Operation and Maintenance Manuals and relevant service literature. Failure to follow the instructions or heed the warnings could result in injury or death. Proper care is your responsibility.

Illustration 1	g06297869
(1) Accumulator plug

Illustration 2	g06297870
(2) Modular line ends to be loosened and retorqued (3) Modular line ends to be loosened and retorqued (4) Leak

1. Remove the accumulator plugs (1) and inspect the outer wall of the common rail system for leaks after 300 hours of operation (one time).

   If a leak is found proceed to Step 2. If no leaks are found reassemble and return the engine to service.

2. Loosen and retorque the modular lines to the accumulators where fuel is present.

   Note: Both ends of the modular lines (2) and (3) must be loosened.

   1. Tighten the nuts of tube assembly to a torque of 38 ± 3 N·m (28 ± 2 lb ft).

   2. Tighten the nuts of tube assembly to a final torque of 100 ± 5 N·m (74 ± 4 lb ft).

3. Perform the "Fuel System Functional Test" using Cat ET to ensure that all fuel system issues are corrected.

4. Inspect the fuel system for leaks after 300 hours of operation.

5. If the procedure did not correct the issue, contact your Cat dealer Technical Communicator (TC). For further assistance, your TC can confer with the Dealer Solutions Network (DSN).