Baroness LM331, Service Manual, Page: 58 / 165

Measurement
Note
The most effective way of solving problems in
the hydraulic system is to use a measuring
instrument such as a pressure gauge for
measurement.
Before pressure measurement
Important
Before concluding that the problem in the
hydraulic system is caused by the hydraulic
equipment, every part of the hydraulic system
must be checked for issues related to
hydraulic oil fill, hydraulic oil filter, loosening of
fasteners, lack of adjustment and so on.
Note on pressure measurement
Warning
As mentioned in the measurement procedure,
the use of a pressure gauge not meeting the
pressure measurement standard may result in
damage to the pressure gauge or leakage of
high-pressure oil. Be extremely careful with
high-pressure oil as it may pierce your skin,
resulting in personal accidents.
Warning
Carry out pressure measurement with two or
more persons.
One person should be in the driver
’
s seat to
operate the machine and the other person
should engage in measurement and
recording.
Caution
When checking the hydraulic circuit for
pinhole leaks or oil leakage from nozzles, do
not use your hands. Use items such as paper
or corrugated cardboard to find leakage
points. Be extremely careful with high-
pressure oil as it may pierce your skin,
resulting in personal accidents.
Always clean the machine before pressure
measurement. Remember that the machine
must always be kept clean for pressure
measurement. Contamination may lead to
clogging or breakage of the hydraulic circuit. 1.
Review the measuring method before
starting measurement.
Before measurement, check for poor
adjustment, clogging or breakage.
Warm up the hydraulic oil before starting
pressure measurement.
Warning
Be sure to depressurize the hydraulic system
before inspecting or repairing it.
When hydraulic equipment is removed, cap
or plug it to prevent contamination of the
hydraulic system.
When using a measuring instrument such as
a pressure gauge, connect the in/out hoses
correctly. Never connect the other way round
to prevent breakage of the hydraulic system
and measuring instrument.
Screw in the hydraulic fitting by hand till it
touches the other side lightly, then fasten
with a spanner.
Fit hoses and measuring instruments in such
a way as to avoid contact with the movable
part of the machine.
After connecting a measuring instrument,
check the amount of oil in the hydraulic tank.
Check to see that the engine is in good
condition. Carry out pressure measurement
with the engine running at maximum speed.
In case there is any problem in the traveling
circuit, carry out the following measurement.
Charge relief valve pressure
Traveling relieve valve pressure
In case there is any problem in the raise/
lower or steering circuit, carry out the
following measurement.
Relief valve pressure
Make sure that there is no oil leakage.
In the event of leakage, stop the engine, set
the oil stopper, and check the amount of oil
in the hydraulic tank.
Add oil if necessary.
2.
3.
4.
5.
6.
7.
8.
9.
10.
11.
[1]
[2]
12.
[1]
13.
LM331
Hydraulic system
Page 4-32
Measurement