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Groundsmaster 4000--D/4010--D Hydraulic SystemPage 4 -- 65
Procedure for Steering and Lift/Lower Gear Pump
Flow Test
NOTE: Output from the steering and lift/lower gear
pump section is equally divided by a proportional valve
to provide flow to the steering circuit and the lift circuit.
The p roportional valve is in the fan drive manifold.
NOTE: While rotating the steering wheel and raising
thedecksatthesametimewiththeenginerunningat
high idle speed (2870 RPM), an indication of gear pump
damage may be the steering wheel getting hard to turn
and/or the cutting decks raising very slowly.
1. Make sure hydraulic oil is at normal operating tem-
perature by operating the machine under load for
approximately ten (10) minutes. Make sure the hydrau-
lic tank is full.
2. Park machine on a level surface with the cutting
decks lowered and off. Make sure engine is off and the
parking brake is applied. Raise and support seat to gain
access to the gear pump.
CAUTION
Prevent personal injury and/or damage to equip-
ment. Read all WARNINGS, CAUTIONS and Pre-
cautions for Hydraulic Testing at the beginning
of this section.
3. With the engine off and cutting decks lowered, dis-
connect the hydraulic hose from the 90
o
fitting in the
third gear p ump section which supplies the steering and
lift/lower circuits (Fig. 50).
IMPORTANT: Make sure that the oil flow indicator
arrow on the flow gauge is showing that the oil will
flow from the pump section, through the tester and
into the hydraulic hose.
4. Install tester (flow and pressure) in series between
the fitting and the disconnected hose. Make sure the
flow control valve on tester is fully open.
IMPORTANT: The pump is a positive displacement
type. If pump flow is completely restricted or
stopped, damage to the pump, tester or other com-
ponents could occur.
5. Start the engine and move throttle to high idle speed
(2870 RPM). DO NOT engage the cutting decks.
6. While watching pressure gauge on tester, slowly
close flow control valve until 1000 PSI (69 bar) is ob-
tained on gauge. Verify t hat engine speed continues to
be 2870 RPM.
GAUGE READING TO BE: Flow approximately 7
GPM ( 26 LPM) at 1000 PSI (69 bar).
NOTE: If engine speed drops below 2870 RPM, pump
flow will decrease.
7. Open flow tester control valve, stop engine and re-
cord test results.
8. If a pressure of 1000 PSI (69 bar) could not be ob-
tained or flow is lower than 6GPM(23LPM),checkfor
restrictioninpumpintakeline.Ifintakelineisnotre-
stricted, consider that gear pump section for steering
and lift/lower circuits is worn or damaged.
9. When testing is complete, remove tester and recon-
nect hose to pump fitting.
1. Gear pump
2. Fan drive manifold
3. Steering/lift supply hose
4. 90
o
fitting
Figure 50
1
2
3
4
Hydraulic
System