Gradall 534B (9020-7317) Service Manual - Manual (Page 121)

Before testing the hydraulic system it is important
that you read and understand System Operations of
534B, and the Safety Manual. Then make the
following checks:
Engine RPM : Using tachometer, check engine rpm
at both idle speed and high speed (with the
accelerator fully depressed). The tachometer
reading should be:*
Idle............................900 rpm approx.
High ........................2800 rpm approx.
Next, check with the boom retracted fully while
holding back on the control lever. It should
about 2600 rpm.
*If unable to get proper rpm call in a qualified
engine mechanic and follow manufacturer ’s
recommendations.
Reservoir: Drain some oil from the plug at the
bottom of the reservoir into a glass bottle and allow
it to settle. If dirt or water is present, drain and clean
reservoir, replace filter and fill with new hydraulic
fluid to proper level. Start engine and bring oil to
operating temperature. Never test pressures with
cold oil.
GRADALL LOED MATERIALS HANDLER 534B TESTING AND ADJUSTING
PUMPS
Speed of hydraulic functions is determined by the
volume of oil provided for the functions. Power
(force) is determined by the pressure built up to
perform work. Slow action in a circuit indicates that
either the pump is not putting out the required
volume or that leakage is taking place.
The ability of a pump to build up pressures strong
enough to open the pump relief valve is one
indication of pump efficiency. However, it is
possible for the pump to build up this pressure, and
still not be putting out the required volume of oil.
BLEEDING OFF CIRCUIT PRESSURE
To remove a high pressure build-up in a circuit,
physically drain off oil. This can be done for
relieving circuit pressures or for situations such as
removal of a Mini-check test port.
With a hydraulic failure or an engine shut-off, it is
necessary to bleed the pilot line going to the lock-out
valve. Remove one end of the line and drain the fluid
into an open container. For instance if under these
conditions the boom is raised, it is necessary to bleed
the line to lower the boom.
Gradall is a registered trademark for hydraulic excavators,
hydraulic material handlers and attachments built by The
Gradall Company
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WARNING: DO NOT OPERATE
GRADALL MATERIALS HANDLER
UNLESS FLUID IS AT PROPER
LEVEL.
FORM 8478
Place forks on ground and shut off engine. Set
parking brake.
Install Mini-check hose, less the gage. Point the
hose towards oil container. Use a covered
container to avoid splash.
Drain off and collect the oil.
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