Table of Contents
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Section E
15 - 1
Hydraulic System
- Fixed Flow
Fault Finding Contents
Introduction
Lack of power in all hydraulic functions
All hydraulic rams slow to operate
One hydraulic service fails to operate or is
slow to operate
The engine tends to stall when the
hydraulics are under load
A spool is sticking
Leaking Oil Seal (Control Valves)
Ram creep
Hydraulic oil becomes too hot
Fault
Lack of power in all hydraulic functions.
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Hydraulics
Fault Finding
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Probable Cause
Insufficient hydraulic fluid.
Hydraulic leaks in system.
Engine performance.
Main relief valve (MRV)
setting incorrect.
Low pump flow.
Hydraulic tank breather
Tank filter by-pass valve
Unloader valve pressure
setting too high
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Introduction
The purpose of this section is to help you trace hydraulic
faults to a faulty unit (valve, actuator, ram etc). Once you
have t rac ed t he f ault y unit , ref er t o t he ap p ro p riat e
dismantling, inspecting and test instructions given elsewhere
in the hydraulics section.
To help identify circuits, valves, rams etc mentioned in the
fault finding procedures, refer to the hydraulic schematic
diagrams (near the beginning of the Hydraulics Section).
1
B ef o re yo u b eg in f ault f ind ing , read t he Saf et y
information at the beginning of this manual.
Make simple checks before say, stripping a major
2
component.
3
Make sure that the hydraulic fluid is at correct working
temperature (50 ° C, 122 ° F).
4
What ever the fault, check the condition of the hydraulic
fluid. Drain and replace if necessary.
5
Make any relevant electrical checks before moving on
to the hydraulics.
6
Be sure to remove ALL contamination and if possible
identify its origin. It may be part of a component from
elsewhere in the circuit.
7
Rep lac e any seals suc h as ' O' ring s b ef o re re-
assembling hydraulic components.
Check for leaks and top up as required.
Check hoses, replace as required.
Check engine performance, see
transmission section for stall speed
test procedures.
Check and adjust as required.
Check pump flow, if required service or
replace pump.
Clean or replace the breather
Check condition of hydraulic filter
Check pressure setting of the
unloader valve.
Section E
15 - 1
Action
..... continued
Issue 1
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