Baroness LM551, Service Manual, Page: 42 / 213

Air Bleeding
Important
When you replace or repair the motor, pump,
cylinder, etc., make sure that the hydraulic
system is properly connected.
Make sure that air is bled to avoid
malfunction.
Important
When you replace or repair hydraulic parts, be
sure to replace the hydraulic oil filter.
Move the machine to level surface.
Apply the parking brake, and then lower the
operating machine to the ground.
Stop the engine, and then remove the key.
Make sure that the hydraulic equipments and
hydraulic fittings are securely tightened.
When there is any malfunction of the
hydraulic system or dirt is present, clean the
hydraulic system, hydraulic tank, and suction
filter, if attached, and then replace the
hydraulic oil and filter.
Make proper adjustment and connection,
and make sure that there are neither broken
parts nor oil leakage.
Make sure that the traveling pedal or the
traveling lever and all the drives of the
operating machine are in neutral position.
Start the engine for 10 seconds, and check
for any oil leakage and the condition of the
hydraulic equipment.
Perform this operation twice.
Jack up the entire traveling portion of the
machine, and then use jack stands or any
proper blocks to support it firmly.
"Jacking Up The Machine" (Page 3-18)
Start the engine and drive the traveling
portion while the engine is running at low
rpm.
The charge pump sucks oil, air in the
hydraulic system will be bled in about 30
seconds, and then the circuit will be filled
with hydraulic oil. 1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
After the hydraulic circuit is filled with
hydraulic oil, operate the up/down cylinder
several times.
Stop the engine immediately when the
cylinder does not move within 10 to 15
seconds or if there is any noise from the
pump. Then carry out the following
inspections.
Loose, malfunction of the filter or suction
line
Loose, malfunction of the hydraulic metal
fitting of the pump
Block of the suction line
Block of the charge relief valve
Malfunction of the charge pump
Proceed to the following operation when the
up/down cylinder moves within 10-15
seconds.
Lower the machine to the ground.
Carry out the following operations when the
traveling pump or the traveling motor has
been removed.
Run for 10 minutes so as to rotate the
traveling portion slowly.
Then, gradually increase operation load
while running for 10 minutes.
Stop the machine, check the amount of
hydraulic oil and add as necessary.
Make sure that there is no oil leakage.
Check all of the connections.
Check that the traveling is in neutral
position.
Adjust the neutral position if necessary.
11.
[1]
[2]
[3]
[4]
[5]
12.
13.
[1]
[2]
[3]
[4]
LM551
Hydraulic System
Page 4-4
General Inspection and Repair