GEAR-PUMP DRIVE 1406717 - Caterpillar

TECHNICAL INFORMATION BULLETIN OCTOBER 20, 2004
BACKHOE LOADERS 432D (BLD1-UP)
432D (TDR1-368)
432D (WEP1-1318)
442D (BRY1-UP)
442D (BRG1-UP)
442D (TBD1-298)
442D (SMJ1-304)
Component Codes 5811SUBJECT: HYDRAULIC INSTABILITY ON 432D BACKHOE LOADERS AND 442D BACKHOE LOADERS WITH THE 175-6918 LOAD CONTROL VALVE GROUP
PROBLEM:
Reports have been received from the field that the boom or stick may judder during operation. The judder has primarily occurred when the boom is being slowly lowered. On about 10% of the occurrences, the judder has occurred when the stick was being extended.
SOLUTION:
The original restrictor that was in the boom cylinder load control valve group needs to be replaced. Use the following procedure in order to replace the restrictor.
Lower the boom and stick assembly to the ground. Make sure that the stick cylinder is fully retracted.
Turn off the engine. Follow the procedures in the hydraulic system testing and adjusting module for your machine in order to relieve all of the pressure in the hydraulic system.
Remove bolt (1) from the load control valve group.
4. Remove the seal (2) from the original restrictor. Make sure that seal (2) is installed on the new 257-0128 Restrictor. Install the new 257-0128 Restrictor and seal (2) in the load control valve group. Torque the new 257-0128 Restrictor to 22Nm (16 Lbft).
The new 257-0128 Restrictor is available through the Caterpillar Parts System. The new 257-0128 Restrictor became effective in production with the following machines.
432D (TDR369-UP)
432D (WEP1319-UP)
442D (TBD299-UP)
442D (SMJ305-UP)
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