Return to Master Table of Contents PUMP INPUT POWER CONTROL PUMP REGULATOR ADJUSTMENT WARNING! This procedure should be done with two people. To reduce the chance of accident or unintended start-up, one person should remain at the operator’s control stand while checks and adjustments are made. To perform these adjustments accurately the use of a flow meter is strongly recommended, as is consulting the factory (before starting work) to validate the need for making regulator adjustments. Vent hydraulic pressure from the reservoir before breaking the seal on fittings to install the flow meter kit.
(Refer to the "Flow meter Installation and Testing" procedure.) IMPORTANT Before starting this procedure or going on to make any changes of adjustment settings, Verify engine output to the rated speed - 2,150 ±50 RPM. Permanently mark setscrew positions at the current regulator control setting. Use a scribe or other permanent marker to identify a reference point on adjusting screws with a corresponding reference on the body of the valve. The adjustment process affects a complex balance and could require some time to complete. If adjustment has to be interrupted or postponed, reference marks at the adjustment point allow immediate restoration of original performance.
This adjustment procedure is normally performed: If the engine is being consistently overloaded (and engine troubleshooting shows engine performance to be at or above rated output); If reduced cylinder speed and diminished work performance provide an indication that rated, maximum pump flow may not be available (and all other troubleshooting gives no indication of other flaws or hydraulic system defects); If pump output is out of balance and one pump is failing to keep up with the output flow of the other. To check pump imbalance without a flow meter, travel the excavator forward on flat, level terrain.
If the machine veers off despite neutral control input and even, balanced track adjustment, the pump which supplies output to the track frame toward which the excavator is veering is weak. Page 17 Hydraulic System Troubleshooting, Testing and Adjustment