Toro Groundsmaster 4500-D, Service Manual

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Groundsmaster 4500--D/4700--D Hydraulic System (Rev. A) Page 4 -- 49
Procedure for Traction Circuit Reducing Valve (PR1)
Pressure Test
1. Make sure hydraulic oil is at normal operating tem-
perature by operating the machine for approximately 10
minutes. Make sure the hydraulic tank is full.
2. Park machine on a level surface with the cutting units
lowered and off. Make sure engine is off and the parking
brake is engaged.
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. Connect a 1000 PSI gauge to test port on 2WD/4WD
control manifold under operator’s seat (Fig. 49).
4. Start the engine and put throttle at full engine speed
(2800 + 50 RPM) .
5. Sit on seat, apply brakes fully, and slowly depress the
traction pedal in the reverse direction. While pushing
traction pedal, look at pressure reading on gauge:
GAUGE READING TO BE 420 to 470 PSI .
6. Pressure reducing valve (PR1) is located on the low-
er, rear side of the 2WD/4WD control manifold (Fig. 50).
Adjustment of this valve can be performed as follows:
NOTE: Do not remove the valve from the hydraulic
manifold for adjustment.
A. To increase pressure setting, remove cap on re-
ducing valve and turn the adjustment socket on the
valve in a clockwise direction. A 1/8 turn on the sock-
et will make a measurable change in pressure set-
ting.
B. To decrease pressure setting, remove cap on re-
ducing valve and turn the adjustment socket on the
valve in a counterclockwise direction. A 1/8 turn on
the socket will make a measurable change in pres-
sure setting.
C. Recheck pressure setting and readjust as need-
ed.
1. 2WD/4WD control manifold (GM 4500--D shown)
2. Relief valve test port
Figure 49
2
1
1. Manifold: lower side 2. Reducing valve (PR1)
Figure 50
2
1
Hydraulic System