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Workman HD Series Page 9 − 29 Hydraulic System
Primary Hydraulic System Relief Valve Pressure
Test:
The relief valve for the steering and lift circuits is integ-
rated into the steering control valve. If both steering and
lift operations perform poorly, perform the relief valve
pressure test and primary hydraulic system gear pump
flow test (see Primary Hydraulic System Gear Pump
Flow Test in this chapter).
NOTE: If available, using a flow meter with pressure
gauge that has at least a 5 GPM (16 LPM) capacity in-
stead of a pressure gauge (as described in this test) will
allow performing the relief valve test and the pump (P2)
flow test with the same test configuration (see Primary
Hydraulic System Gear Pump Flow Test in this chapter.
1. Park machine on a level surface with the cutting units
lowered and PTO switch off. Make sure engine is off and
the parking brake is engaged.
2. Read Precautions for Hydraulic Testing in this
chapter.
3. Disconnect hose connection on primary hydraulic
system gear pump leading to the steering control valve
(Fig. 21 or 22).
4. Install T−connector with test gauge between the gear
pump and the disconnected hose.
5. Make sure the hydraulic reservoir (transaxle) is full
after connecting the T−connector with test gauge.
6. Make sure steering wheel is positioned so the front
wheel points directly ahead.
7. Start engine and depress accelerator pedal so en-
gine is running at high idle (3600 RPM).
8. Make sure hydraulic fluid is at normal operating tem-
perature by operating the machine for approximately 10
minutes.
9. Watch pressure gauge carefully while turning the
steering wheel completely in one direction and holding.
CAUTION
Do not allow pressure to exceed 2000 PSI. Hold
steering wheel at full lock only long enough to
get a system pressure reading. Holding the
steering wheel against the stop for an ex-
tended period may damage the steering con-
trol valve.
10.System pressure should reach 1800 to 1900 PSI
(124 to 131 Bar) as the relief valve opens.
11. Return steering wheel to the center position, release
accelerator pedal and shut off engine.
12.If relief pressure is incorrect, inspect for a worn or
stuck relief valve in steering control valve (see Steering
Control Valve Service in this chapter).
13.Disconnect T−connector with test gauge and recon-
nect hydraulic hose to gear pump.
14.Make sure the hydraulic reservoir (transaxle) is full
before returning the vehicle to service.
Hydraulic
System