Service Manual

Groundsmaster 7200/7210 Hydraulic SystemPage 4 – 41
The Lift Cylinder Internal Leakage Test should be per-
formed if a cutting deck (or implement) raise and lower
problem is identified. This test will determine if the lift cyl-
inder is faulty.
NOTE: Raise/lower circuit operation will be affected by
lift cylinder binding, extra weight on the cutting deck (or
implement) and/or binding of lift components. Make
sure that these items are checked before proceeding
with the lift cylinder internal leakage test.
Procedure for Lift Cylinder Internal Leakage
Test:
1. Park machine on a level surface with the PTO switch
OFF. Position the cutting deck (or implement) in a par-
tially raised position and turn the engine off. Apply the
parking brake.
2. Under both sides of the cutting deck (or implement),
use a jack to raise the cutting deck (or implement) slight-
ly. This will remove the load from the lift cylinder and re-
lieve lift cylinder hydraulic pressure. Support both sides
of the cutting deck (or implement) with jack stands to
prevent the lift cylinder from retracting.
3. Thoroughly clean the area around the hydraulic hose
end at the barrel end of the lift cylinder. Disconnect the
hydraulic hose from the lift cylinder barrel end fitting
(Fig. 27).
IMPORTANT: When capping the lift cylinder fitting
and hydraulic hose end, use a steel cap and plug to
ensure that fluid leakage will not occur. Plastic
plugs will not hold hydraulic pressure that will be
developed during this test procedure.
4. Place a steel cap on the open lift cylinder fitting to
seal the lift cylinder. Also, install a steel plug in the open
end of the disconnected hose to prevent leakage or con-
tamination.
5. Remove the jack stands from under the cutting deck
(or implement). The cutting deck (or implement) should
settle slightly and then be supported by the capped lift
cylinder.
6. Place a piece of tape on the lift cylinder rod near the
rod end (Fig. 28). Measure and record the distance from
the lift cylinder collar to the tape location.
7. Leave the machine parked for 4 hours and monitor
the lift cylinder. The weight of the cutting deck (or imple-
ment) will cause the lift cylinder to gradually retract. Use
the change in distance from the lift cylinder collar to the
tape location to determine lift cylinder rod movement.
A. If the cutting deck (or implement) is still sus-
pended after 4 hours and lift cylinder rod movement
is less than 1/4” (6.4 mm), consider that the lift cylin-
der is in good condition. A lift cylinder in good, usable
condition will show minimal rod movement.
B. Rod movement in excess of 1/4” (6.4 mm) after 4
hours indicates a lift cylinder with internal seal dam-
age or excessive internal wear. Replace or repair the
lift cylinder (see Lift Cylinder and Lift Cylinder Ser-
vice in the Service and Repairs section of this chap-
ter).
8. Once lift cylinder condition has been determined,
use a jack to raise both sides of the cutting deck (or im-
plement) slightly which will remove the load from the lift
cylinder. Support both sides of the cutting deck (or im-
plement) with jack stands. Remove the cap from the cyl-
inder fitting and the plug from the hydraulic hose.
Connect the hydraulic hose to the lift cylinder fitting.
9. Remove tape from lift cylinder rod.
10.Remove the jack stands from under the cutting deck
(or implement). Start engine and operate lift cylinder
through several raise and lower cycles. Stop the engine
and check for any leakage.
11. Check oil level in hydraulic reservoir.
1. Lift cylinder 2. Barrel end hose
Figure 27
1
2
1. Lift cylinder collar 2. Tape
Figure 28
1
2
MEASURED
DISTANCE
Hydraulic
System