Service Manual

Groundsmaster 4300--DHydraulic System Page 4 -- 54
Lift Cylinder Internal Leakage Test
Figure 55
LEFT FRONT (#4) LIFT CYLINDER TEST SHOWN
GEAR
PUMP
LIFT
CONTROL
MANIFOLD
TO STEERING
CONTROL VALVE
INTERNAL
CASE
DRAIN
PUMP (P5)
TO DECK CONTROL MANIFOLD
(REAR CUTTING UNITS)
(FRONT CUTTING UNITS)
TO DECK CONTROL MANIFOLD
FROM MOW CONTROL
MANIFOLD
(PARTIALLY
RAISED)
PLUG CAP
CHECK FOR
CYLINDER
EXTENDING
The lift cylinder internal leakage test should be per-
formed if a cutting deck raise and lower problemis iden-
tified. This test will determine if a lift cylinder is faulty.
NOTE: Cuttingdeckraise/lowercircuitoperationwillbe
affected by lift cylinder binding, extra weight on the cut-
ting decks and/or binding of lift components. Make sure
that these items are checked before proceeding with lift
cylinder internal leakage test.
Procedure for Lift Cylinder Internal Leakage
Test:
NOTE: When performing the lift cylinder internal leak-
age test, the cutting decks should be attached to the lift
arms.
1. Park machine on a level surface with the PTOswitch
OFF. Position thecutting decks in the turn--around posi-
tion and turn the engine off. Apply the parking brake.
2. For the lift cylinder that is to be tested, use a jack to
raise the lift arm slightly. This will remove the load from
the lift cylinder and relieve lift cylinder hydraulic pres-
sure. Leave the jack under the lift arm to support the lift
arm and to prevent the lift arm from lowering.
NOTE: If either of the rear lift cylinders is being tested,
both rear lift arms need to be supported.
3. Thoroughly clean the area around the end of the hy-
draulichoseat the rod endof the lift cylinder.Disconnect
the hydraulic hose from the lift cylinder rod end fitting
(Fig. 56).