Groundsmaster 4300--D Hydraulic SystemPage 4 -- 45
3. Read Precautions For Hydraulic Testing in this sec-
tion.
CAUTION
Before opening hydraulic system, operateall hy-
draulic controls to relieve system pressure and
avoid injury from pressurized hydraulic oil. See
Relieving Hydraulic System Pressure in the Gen-
eral Information section of this chapter.
4. Raise and support operator seat to allow access to
hydraulic deck control manifold.
5. Thoroughlyclean junction of hydraulicinlet hoseand
deck motor fitting on left side cutting deck for the relief
valve to be tested. Disconnect hose from deck motor fit-
ting (Fig. 46):
#2 cutting deck (left rear) for relief valve (PRV1)
#4 cutting deck (left front) for relief valve (PRV2)
IMPORTANT: Make sure that the oil flow indicator
arrow on the flow meter is showing that the oil will
flow from thedisconnected hose,through thetester
and into the deck motor.
6. Install tester with pressure gauge and flow meter in
series with the disconnected hose and hydraulic fitting
on deck motor. Make sure the flow control valve on
tester is fully open.
7. After installing tester, start engine and run at idle
speed. Check for any hydraulic leakage from test con-
nections and correct before proceeding with test.
8. Move throttle to full speed (3200 RPM).
CAUTION
Keep away from cutting decks during test to pre-
vent personal injury from rotating blades.
9. Have a second person occupy seat, press PTO
switch to ONand then movejoystick lever forward toen-
gage cutting decks.
IMPORTANT: When performing this test, do not
hold over relief any longer than necessary to obtain
pressure reading.
10.Watch pressure gauge carefully while slowly closing
the tester flow control valve. As the relief valve lifts, the
pressure gauge needle will momentarily stop.
NOTE: Once the relief valve has opened, system pres-
sure may continue to increase.
11.As the relief valve lifts, system pressure should be:
Approximately 2500 PSI (175 bar) for relief valve
(PRV1)
Approximately 3500 PSI (241 bar) for relief valve
(PRV2)
12.Open the tester flow control valve, disengagecutting
decks and stop the engine.
13.If pressure is incorrect, remove PRV valve on mow
manifold and clean or replace valve (see Deck Control
Manifold Service in the Service and Repairs section of
this chapter). Also, if pressure is still low after valve ser-
vice, check for restriction in pump intake line. Gear
pump (P2) (front cutting deck circuit) and/or pump (P1)
(rear cutting deck circuit) c ould also be suspected of
wear, damage or inefficiency (see Gear Pump (P1) and
(P2) Flow Test in this section).
14.After testing is completed, make sure that engine is
stopped, then relieve hydraulic system pressure (see
Relieving Hydraulic System Pressure in the General In-
formation section of this chapter). Remove tester from
machine and connect hydraulic hose to deck motor fit-
ting.
15.Lower and secure operator seat.
1. Cutting deck motor (#2 shown)
2. Deck motor i nlet hose
Figure 46
1
2
FRONT OF MACHINE
Hydraulic
System
