Insufficient Bolt Clamp Load For The Scavenge Pump Used On Certain C175 Off-Highway Truck Engines {1312} Caterpillar

Off-Highway Truck/Tractor

797F (S/N: LAJ1-UP; WSP1-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 block pan rail of certain C175 engines can experience fretting which could lead to loss of bolt load and pump failure.

Solution

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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.

If the pan rail has no fretting ("new" or "as new" condition), a scavenge pump installed with friction shims at the mounting feet of the scavenge pump should be used.

Table 1 contains the required parts to install a scavenge pump equipped with friction shims at the mounting feet.

Table 2 contains the required tools for this procedure.

Loctite^® 243 Blue Threadlocker

If the pan rail has signs of fretting but the scavenge pump has not failed, the current pump should continue to be used.

The following procedure should be used at 2000-hour increments from the initial reinstall of the pump.

If the pan rail has signs of fretting and the pump must be changed, the following procedure should be used at 2000-hour increments from the initial install of the new pump.

1. Refer to the reference below for specific instructions to remove the front section of the oil pan.

   Reference: Disassembly and Assembly, KENR6052, "Engine Oil Pan Remove C175".

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   Illustration 1	g06426648
   (1) 275-2200 Bolt (2) 275-2200 Bolt (3) 160-8750 Bolt (4) 160-8750 Bolt (5) 319-3527 Hard Washer

2. Starting with bolt (1), remove and discard the bolt.

   1. Ensure that the threads in the block are clean and free of oil, debris, or adhesives prior to installing the new fastener.

      Note: If necessary, run a thread tap by hand to clear the threads of debris.

   2. To condition the threads on the new bolt, torque the new bolt to 100 N·m (74 lb ft), and then remove the new bolt.
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   Illustration 2	g06426712
   (T1) Loctite® 243 Blue Threadlocker

3. Apply tooling (T1) along the thread engagement length of 20 mm (0.8 inch) on the new bolt, as shown in the above illustration.

   Note: Prevent the Loctite^® 243 Blue Threadlocker from contacting the bolt underhead, as this can cause increased assembly friction resulting in reduced clamp load of the bolt.

   1. Torque the new bolt to 100 N·m (74 lb ft).

      Note: Torque process should be completed within 10 minutes of applying tooling (T1) and the temperature must be above 15° C (59° F).

4. Return to Step 1 and repeat this procedure for the remaining bolts called out in Illustration 1.

   1. Proceed to the next step after each bolt has been replaced.

5. Refer to the reference below for specific instructions to install the front section of the oil pan.

   Reference: Disassembly and Assembly, KENR6052, "Engine Oil Pan Install C175".