Service Manual

Rev. J
Greensmaster 3250--D
Hydraulic System (Rev. I)
Page 4 -- 43
Procedure for Lower Cutting Units Relief Valve
(R2)
Pressure
Test
1. Make sure hydraulic oil is at normal operating tem-
peraturebyoperatingthemachineforapproximatelyten
(10) minutes.
2. Park machine on a level surface with the cutting
units lowered. Make sure engine is off and the parking
brake is engaged. Make sure the hydraulic tank is full.
CAUTION
Before continuing further, read and become fa-
miliar with Precautions for Hydraulic Testing.
3. Measure and record charge relief valve (R4) pres-
sure(seeChargeReliefValve(R4)PressureTestinthis
section).
4. Use same tester connections as described in Gear
Pump(P2) Flow Test. Fully open control valve on the
tester.
5. Startengine and move throttle tofullspeed (2750 +
50 RPM). Make sure that cutting units are fully lowered
and engage the cutting units.
Note: The LOWER function is electrically timed and
automatically turns off after approximately six (6) sec-
onds.
6. Watch pressure gauge carefully while moving the
Raise/Lower -- Mow Control lever to LOWER and note
pressurethatreliefv alve opens. Shut offengine and re-
cord test results.
Note: While performing this hydraulic test, if relief
pressurecannotbedeterminedwithintheLOWERfunc-
tion six (6) second timeframe, repeat this test proce-
dure.
Note: The lower cutting units relief valve (R2) is in se-
ries with charge relief valve (R4). ( R4) pressure will af-
fect (R2) pressure.
7. The lower cutting units relief pressure (R4) should
be:
A. For machines with serial number under
220999999,reliefpressureshouldbe150PSI(10.3
bar)higherthan chargerelief(R4) pressure(e.g.
if charge relief valve pressure is 100 PSI (6.9 bar),
the lower relief valve (R2) pressure should be
approximately 250 PSI (17.2 bar)).
B. For machines with serial number over
230000000,reliefpressureshouldbe400PSI(27.6
bar)higherthan chargerelief(R4) pressure(e.g.
if charge relief valve pressure is 100 PSI (6.9 bar),
the lower relief valve (R2) pressure should be
approximately 500 PSI (34.5 bar)).
8. Ifrelief valve (R2)pressureis incorrect,adjustrelief
valve (R2) (see Adjust Manifold Relief Valvesin the Ad-
justments section of this Chapter). Retest relief valve
pressure if adjustment is performed.
9. After testing is complete, disconnect tester from
gear pump and hose. Reconnect hose to hydraulic fit-
ting on pump.
Figure 16
FRONT
RELIEF
VALVE (R2)
S4
S3
S1
S2
MANIFOLD FROM MACHINE
WITH SERIAL NUMBER
UNDER 270000000 SHOWN
Figure 17
FRONT
RELIEF
VALVE (R2)
S4
S3
S1R1
S2
MANIFOLD FROM MACHINE
WITH SERIAL NUMBER
OVER 270000000 SHOWN
Hydraulic
System