Usage:
June 29, 2002
U-143
A-105
AU-108
S-108
H-106
O-119
After failure only |
PRODUCT SUPPORT PROGRAM FOR REWORKING THE BRAKE, PILOT, AND STEERING PUMP GROUP ON CERTAIN M318 AND M320 WHEELED EXCAVATORS |
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4007 4306 5073 5085 |
PS50499
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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.
TERMINATION DATE
June 30, 2004PROBLEM
The joint between the pilot pump input gear, and pilot pump bearing shaft can fail, causing loss of pilot pump pressure. Affected pilot pump is 1877419 Pump Gp.-Gear. When the pilot pump is removed, it can be noted the gear will spin freely on the bearing shaft.AFFECTED PRODUCT
Model | Identification Number |
M318 | 8AL02430-03362
6ES00243-00301 8SS00479-00619 |
M320 | 6WL00531-00922
9PS00299-00471 |
PARTS NEEDED
Qty | Part Number | Description |
1 | 7C1782 | Gear |
1 | 7W1165 | Gasket |
1 | 1712989 | Locknut |
1 | 1532666 | Bearing |
SERVICE CLAIM ALLOWANCES
Product smu/age whichever comes first |
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Parts |
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0-60 mos |
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NOTE: This is an 8-hour job. |
PARTS DISPOSITION
Handle the parts in accordance with your Warranty Bulletin on warranty parts handling.Attach. 1: Rework Procedure
Rework Procedure
Disassembly
- Remove and cover lines groups attached to pilot pump.
- Loosen 3 bolts retaining 178-8650 pilot pump mounting bracket to engine.
- Remove and retain 8T4136 bolt attaching rear pilot pump mounting bracket to engine mounting bracket.
- Remove 187-7419 pilot pump group from engine. Retain mounting bolts for later use.
- Loosen and remove the 171-2989 locknut from the bearing shaft.
- Remove the 7C1782 gear, the 147-1530 adapter, and the 153-2666 bearing from the pilot pump. Retain the 147-1530 adapter and four bolts for later use.
- Discard the 153-2666 bearing, 7C1782 gear, and the 171-2989 locknut.
- Assembly
- Install new 153-2666 bearing to pilot pump gp. Use the four 7I8935 bolts to retain bearing to pilot pump gp.
- Install 147-1530 adapter to 153-2666 bearing, placing the 7W1165 gasket between the adapter and bearing. See Fig 1.
- Apply Loctite 648 to the new 153-2666 bearing shaft, and install a new 7C1782 gear to the bearing shaft.
- Apply Loctite 648 to the bearing shaft threads, and install a new 171-2989 locknut. Tighten locknut to 75+7Nm.
- Install the pilot pump gp. to engine using bolts removed during disassembly.
- Install the 8T4136 bolt retaining the pilot pump rear mounting bracket to the engine mounting bracket. See Fig. 2.
- Tighten the three bolts retaining the 178-8650 bracket to the engine block.
- Reinstall lines groups to pilot pump.
NOTE: Failure to precisely follow steps
5 through 7 can result in pilot pump bolt failure due to bending stress.
The 178-8650 mounting bracket can be adjusted fore and aft to ensure there
is no gap between the pilot pump rear mounting bracket, and the 178-8650
engine mounting bracket. (NOTE Fig. 2)
1-7W1165 Gasket
2-1471530 Adapter
3-7I8935 Bolt
4-1712989 Lockwasher
5-1532666 Bearing