Service Manual

Groundsmaster 360 Hydraulic SystemPage 4 − 51
The Implement Relief Pressure Test should be per-
formed if a steering or cutting deck raise and lower prob-
lem is identified. This test will determine if the implement
relief valve is operating correctly.
Procedure for Implement Relief Pressure
Test:
1. Make sure hydraulic oil is at normal operating tem-
perature.
2. Make sure that traction drive is correctly adjusted for
the neutral position.
WARNING
Before disconnecting or performing any work on
the hydraulic system, all pressure in the system
must be relieved. See Relieving Hydraulic System
Pressure in the General Information section.
3. Park machine on a level surface with the cutting deck
lowered and off. Make sure engine is off and the parking
brake is engaged.
4. Read Precautions for Hydraulic Testing listed at the
beginning of this section.
5. Raise and support operator seat to allow access to
deck lift manifold.
6. Thoroughly clean deck lift manifold around the plug
in port 3 on rear of the deck lift manifold (Fig. 39). Re-
move plug from deck lift manifold port 3.
7. Install 5000 PSI (345 bar) pressure gauge into deck
lift manifold port 3.
8. Start engine and run at low idle speed (1300 RPM).
Check for any hydraulic leakage from test connections
and correct before proceeding with test.
9. With engine running, move throttle to full speed
(3100 to 3150 RPM).
IMPORTANT: Hold lift switch in the raise position
only long enough to get a system relief pressure
reading. Holding the lift switch in the raise position
for an extended period may damage circuit compo-
nents.
10.Watch pressure gauge carefully while pressing lift
switch to the raise position and holding.
11.When the lift cylinder is fully extended (deck raised)
and the implement relief valve lifts, the pressure gauge
needle will momentarily stop. System pressure as the
relief valve opens should be be approximately 1800 PSI
(124 bar). Return lift switch to the neutral position after
observing relief valve pressure.
NOTE: If lift switch continues to be pressed after the re-
lief valve has opened, system pressure can increase
higher than relief pressure.
12.Stop engine. Record test results.
13.If specification is not met, repair or replace imple-
ment relief valve in gear pump (see Gear Pump Service
in the Service and Repairs section of this chapter). Also
consider a leaking lift cylinder, leaks in the deck lift man-
ifold, a leaking check valve in the steering control valve
or a worn gear pump.
14.Relieve hydraulic system pressure (see Relieving
Hydraulic System Pressure in the General Information
section). Remove pressure gauge from deck lift man-
ifold port. Install plug into deck lift manifold port 3 and
torque plug 25 ft−lb (34 N−m).
1. Deck lift manifold 2. Port 3 location
Figure 38
1
2
1
. Deck lift manifold 2. Port 3 plug
Figure 39
1
2
Hydraulic
System