973C Does Not Track Straight While Digging{3174, 3203} Caterpillar

Track-Type Loader:

973C (S/N: BCP250-312)

Introduction

This Technical Information Bulletin, TIBU4798 is published in order to correct the problem of the 973C not tracking straight while digging.

Problem

The customer will notice one track will stop moving while digging, and the other track will spin. This will cause the machine to turn slightly, and not allow the bucket to penetrate the work straight. This may cause the operator to steer the machine while digging, removing power from the implements. The customer first reported this as a performance problem. If you measure HYSTAT pressure you will notice one track will have a much higher pressure between Forward and Reverse. The correct relief pressure for the HYSTAT is 45000 kPa (6526 psi) in Forward and Reverse. This problem is caused because the wrong Solenoid Valve was installed at the factory. This forces one HYSTAT pump to stroke down when it is put under a load. The problem has been observed on the left track in the Forward direction. The maximum pressure in Forward was 34000 kPa (4931 psi).

Solution

Install the correct 130-6913 Solenoid Valve .