14 - 0
Section E Hydraulics
9803/8550
Section E
14 - 0
Issue 1
Valves
Loader/Excavator Circuit Problem Solving
The purpose of this page is to help you trace hydraulic problems to a faulty unit (valve, actuator, ram etc). Once you have traced
the faulty unit, refer to the appropriate dismantling, inspecting and test instructions given elsewhere in the manual.
To help identify circuits, valves, rams etc. mentioned in the problem solving procedures, refer to hydraulic schematic diagrams.
*
Before you begin problem solving, read the Safety Information at the beginning of this manual.
*
Make simple checks before say, stripping a major component.
*
Make sure that the hydraulic fluid is at correct working temperature (50 °C, 122 °F).
*
Whatever the fault, check the condition of the hydraulic fluid. Drain and replace if necessary.
*
Be sure to remove ALL contamination and if possible identify its origin. It may be part of a component from elsewhere in the
circuit.
PROBLEM CAUSE
Lack of power in all loader/excavator functions. 1, 2, 3, 4, 6, 7, 19
All hydraulic rams slow to operate. 3, 4, 7, 10, 12
One hydraulic service fails to operate or operates slowly. 13, 14, 15, 16, 18
Engine tends to stall when hydraulics are under load. 3, 19
Valve spool sticking. 3, 21, 22, 23, 24, 25, 26, 27, 28
Ram creep. 14, 17
Hydraulic oil becomes too hot. 5, 6, 11, 20
KEY TO CAUSE REMEDY PAGE REF.
1 Insufficient hydraulic fluid. Check for leaks and top up as required. 3/8-1
2 Hydraulic leaks in system. Check hoses, replace as required.
3 Main relief valve (MRV) setting incorrect. Check and adjust as required. E15-1
4 Low loader pump flow. Check pump flow, if necessary service or replace pump.
5 Hydraulic filter clogged. Change hydraulic filter. 3/8-1
6 Filter by-pass valve leaking. Check condition of hydraulic filter. 3/8-1
Check operation of by-pass valve.
7 Charge pressure incorrect. Carry out charge pressure check. E12-3, E12-11
8 Servo pressure low Carry out charge pressure check. E12-3, E12-11
Check for blocked service feed hose or faulty joystick. E12-16
9 Charge pressure/flow low. Carry out charge pressure check. E12-3, E12-11
..... continued
To Next Page
Loading...
Need help?
General
