Service Manual

Multi Pro 5800Hydraulic System Page 5 − 42
Steering/Boom Lift Circuit − Boom Lift Cylinder In-
ternal Leakage Test
The boom lift cylinder internal leakage test should be
performed if a spray boom raise and lower problem is
identified. This test will determine if a boom lift cylinder
is faulty.
The boom lift raise/lower circuit operation will be af-
fected by boom lift cylinder binding, extra weight on the
spray booms and/or binding of lift components. Make
sure that these items are checked before proceeding
with boom lift cylinder internal leakage test.
NOTE: When performing the lift cylinder internal leak-
age test, the lift cylinder should be attached to the spray
boom.
1. Make sure hydraulic oil is at normal operating tem-
perature by operating the machine for approximately ten
(10) minutes.
2. Perform the steering/boom lift circuit − gear pump P2
flow and circuit relief pressure test to make sure that
gear pump P2 and the circuit relief valve are functioning
correctly.
3. Park machine on a level surface with the spray sys-
tem turned Off.
4. With the engine running, use the boom lift switch to
fully lower the spray boom (lift cylinder rod is fully ex-
tended).
5. Turn engine Off and engage the parking brake.
6. Read Precautions for Hydraulic Testing at the begin-
ning of this section.
7. Place a drain pan under the lift cylinder. Clean and
remove hydraulic hose from the fitting on the rod end of
the lift cylinder. Plug the end of the disconnected hose
with a steel hydraulic plug.
8. Remove all hydraulic oil from drain pan and place the
clean pan under the open fitting of the lift cylinder.
WARNING
Keep body and hands away from disconnected
hoses and fittings that might eject hydraulic fluid
under high pressure. Use paper or cardboard,
not hands, to search for leaks. Hydraulic fluid es-
caping under pressure can have sufficient force
to penetrate the skin and cause serious injury. If
fluid is injected into the skin, it must be surgically
removed within a few hours by a doctor familiar
with this type of injury. Gangrene may result from
such an injury.
IMPORTANT: While performing test, do not press
boom lift switch to raise as system damage may oc-
cur.
9. Start engine and run at low idle speed. Have a sec-
ond person observe the open fitting on the lift cylinder.
With the lift cylinder fully extended, momentarily press
the boom lift switch to lower. If oil comes out of the open
fitting when the lift switch is pressed to lower, the lift cyl-
inder has internal leakage and should be inspected and
repaired as necessary (see Lift Cylinder and Lift Cylin-
der Service in the Service and Repairs section of this
chapter). Check drain pan for any evidence of oil that
would indicate lift cylinder leakage.
10.If a boom lift problem exists and the boom lift cylinder
and steering/boom lift circuit − gear pump P2 flow and
circuit relief pressure tested acceptably, the boom lift
control manifold requires service (see Boom Lift Control
Manifold Service in this chapter).
11. After testing is complete, remove plug from the dis-
connected hydraulic hose. Reconnect hose to the lift
cylinder.
12.Start engine and run at low idle speed. Check for hy-
draulic leakage and correct before returning machine to
service.