Groundsmaster 4300--D Hydraulic SystemPage 4 -- 47
3. Read Precautions For Hydraulic Testing in this sec-
tion.
CAUTION
Beforeopeninghydraulicsystem,operateallhy-
draulic controls to relieve system pressure and
avoid injury from pressurized hydraulic oil. See
RelievingHydraulicSystemPressurein theGen-
eral Information section of this chapter.
4. Raise and support operator seat to allow access to
hydraulic pump.
5. Identify suspected faulty pump section to be tested
(Fig.48). Thoroughlyclean junctionof gearpump fitting
and hydraulic outlet hose. Disconnect hose from pump
fitting:
Pump section (P1) for rear cutting decks
Pump section (P2) for front cutting decks
IMPORTANT: Make sure that the oil flow indicator
arrow on the flow gauge is showing that the oil will
flowfromthegearpump,throughthetesterandinto
the hose.
6. Install testerwith pressuregauges andflow meterin
series between disconnected hose and gear pump fit-
ting.Makesuretheflowcontrolvalveontesterisful-
ly 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. Make sure the parking brake is engaged. Move
throttle to full speed (3200 RPM). DO NOT engage the
cutting decks. Use a tachometer to verify that engine
speed is correct.
IMPORTANT: The gear pump is a positive displace-
ment type. If pump flow is completely restricted or
stopped, damage to the pump, tester or other com-
ponents could occur.
9. While watching pressure gauges, slowly close the
tester flow control valve until 1500 PSI (103 bar) is ob-
tained on gauge.
FLOW TESTER READING TO BE: A pump in good
condition should have a flow of approximately 13.6
GPM (51.2 LPM) at 1500 PSI (103 bar).
10.Open the tester flow control valve and stop the en-
gine. Record test results.
11.If flow is less than 12.1 GPM (45.8 LPM) or a pres-
sureof1500PSI(103bar)cannotbeobtained,consider
that a pump problem exists. Check for restriction in
pumpintake line.If intakeis notrestricted, removegear
pump and repair or replace pump as necessary (see
Gear Pump and Gear Pump Service in the Service and
Repairs section of this chapter).
12.After testing is completed, make sure that engine is
stopped, then relieve hydraulic system pressure (see
RelievingHydraulic SystemPressure intheGeneralIn-
formation section of this chapter). Remove tester from
machine and connect hydraulic hose to gear pump fit-
ting.
13.Lower and secure operator seat.
1. Gear pump assembly
2. Pump P1 outlet hose
3. Pump P2 outlet hose
Figure 48
1
3
2
Hydraulic
System
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