SECTION 35 - HYDRAULIC SYSTEM 119
7. FAULT FINDING
7.1 PRELIMINARY CHECKS
If fault finding, pressure and flow testing is carried out
in a systematic manner and the results analyzed, the
malfunction can be readily and accurately identified.
If short-cuts, assumptions and guesses are made,
unnecessary component disassembly or replace-
ment could result. Follow the step-by-step proce-
dures outlined below.
As a first step in the fault finding procedure, several
preliminary checks should be made. These checks
are important because, once they have been per-
formed, they need no longer be considered as a pos-
sible cause of the immediate or reported
malfunction.
Z Check that the hydraulic oil is at the correct level
and of the correct specification.
Z Check the loader, backhoe or any additional acces-
sory such as hydraulic bucket, hammers etc., for
correct assembly or installation and additionally for
signs of external damage that might cause gross
misalignment of structural members.
Z Check in more detail for other mechanical damage
such as kinked, twisted, worn or decayed hoses,
damaged cylinders and bent elements.
Z Do not forget to check underneath the unit for dam-
aged steel tubes, particularly if the unit has been
known to have operated in arduous conditions,
been grounded, or bogged down.
Z Ensure optimum operating temperature of the hy-
draulic oil is achieved.
Z Perform the system pressure and rear pump relief
valve pressure tests.
The above-described preliminary checks assume
that the failure is not linked to the engine perform-
ance. Having performed these checks and failed to
locate the cause of the malfunction, the following
procedures should be adopted:
Z If possible, operate the backhoe and make notes of
the operating characteristics. Cycle each control le-
ver to operate each of the cylinders to the fully ex-
tended and retracted positions.
Z Compare the operating characteristics in the pre-
ceding stage with the malfunctions listed hereun-
der.
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