The 171-8892 Hoist Pumps In Inventory Should Be Inspected Caterpillar

The 171-8892 Hoist Pumps In Inventory Should Be Inspected

Usage:

OFF-HIGHWAY TRUCKS793C (4AR1-UP, 4GZ1-UP) OFF-HIGHWAY TRUCKS

Problem:

The 171-8892 Gear Pump Group have experienced some failures due to clearance of internal components. The potential problems with the 171-8892 Gear Pump Groups in the Caterpillar Parts Distribution System and the pumps used for production units have been corrected.

Solution:

There may be some 171-8892 Gear Pump Groups in the Dealer's Parts Inventory that may have the clearance problem. The 171-8892 Gear Pump Groups in the Dealer's Parts Inventory should be inspected. The pump groups that were built before a certain date in December, 1999 with the "Build-Date Code Identification" that is lower than "JL1958" should be inspected with the procedure in this article.

The "Build-Date Code Identification" is a six digit code that is stamped on the identification label under the Caterpillar part number. An example and explanation follows. Refer to the Table.

X = Year Y = Month NNNN = Production Sequence Number

The pump with the code "JL 1958" would have been manufactured in December, 1999 with the production sequence number of "1958".

Use the following steps to measure the Dynamic Torque of the 171-8892 Gear Pump Group with the "Build-Date Code Identification" that is lower than "JL1958".

1. Secure the pump assembly to a vise or bench.

NOTE: This torque check can be performed with pump standing on end, and the shaft end up.

2. Uncover both ports of the the pump assembly.

3. Rotate the shaft of the pump assembly several time to ensure that the components have loosened up from the storage state.

4. Attach a dial type torque wrench with a range of 0-300 lb-in range to the pump shaft with a 1.5 in socket.

NOTE: The socket is not a tight fit and may not provide a secure coupling to the shaft. There are two possible methods to secure the connection between the torque wrench and the shaft of the pump.

a. Bore a hole and tap a hole in the 1.5 inch socket. Use a set screw to secure the socket to the shaft.

b. Place a shop rag over the splined pump shaft. Place the socket over the end of the pump shaft. Use caution that the socket does not slip when the shaft is rotated. 5.

5. Monitor the torque while the pump shaft is rotated. The maximum reading on the torque wrench should be 14 N·m (125 lb in).

NOTE: The maximum torque is for "Dynamic Torque", not "Break-Away Torque".

6. Return the pumps that have unacceptable torque levels to the Caterpillar Parts Distribution System with an explanation for the rejection.