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Groundsmaster 4500--D/4700--D Hydraulic SystemPage 4 -- 51
Procedure for Reverse Traction Circuit
Reducing
Valve (PR) Pressure
Test
NOTE: When in reverse, pressure reducing valve (PR)
limits the pressure to the rear axle motor to 450 PSI (31
bar) so the rear wheels will not scuff the turf.
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.
1. Make sure hydraulic oil is at normal operating tem-
perature by operatingthe machinefor approximately ten
(10) minutes. Make sure the hydraulic reservoir 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 engaged.
NOTE: The #6 zero leak plug on the inside of rear trac-
tion m a nifold is a zero leak plug t hat has a tapered seal-
ing surface on the plug head. Lightly rap the plug head
using a punch and hammer before using an allen
wrench to remove the plug: the impact will allow plug re-
moval with less chance of damage to the socket head of
the plug.
3. Locate rear traction manifold that is attached to the
front frame next to the left side front wheel (Fig. 41). Re-
move #6 zero leak plug on the inside of rear traction
manifold and install diagnostic fitting (Toro part number
59--7410) into manifold port.
4. Connecta 1000PSI (70bar) pressuregauge with hy-
draulic hose attached to installed diagnostic fitting.
5. Start engine and increase engine speed to high idle
speed. Make sure that HI/LOW speed switch is in the
LOW speed (mow) position and release parking brake.
6. Sit on seat, apply brakes fully and slowly depress the
traction pedal in the reverse direction. While pushing
traction pedal, carefully monitor the pressure gauge to
identify the opening pressure of the pressure reducing
(PR) valve:
GAUGE READING TO BE 420 to 470 PSI (29 to 32
bar) when the pressure reducing (PR) valve opens.
7. Release traction pedal to neutral, stop engine and
record test results.
8. The pressure reducing valve (PR) is located on the
bottom of the rear traction manifold (Fig. 42). If test pres-
sure is incorrect, adjust pressure reducing valve (PR)
(see Adjust Control Manifold Relief Valves in the Adjust-
ments section of this chapter). Recheck pressure redu-
cing valve pressure after any adjustment.
NOTE: The rear traction circuit relief valve (RV) pres-
sure test uses the same pressure gauge position as
used to measure traction circuit pressure reducing valve
(PR) pressure. If necessary, conduct the rear traction
circuit relief valve (RV) pressure test before removing
pressure gauge from rear traction manifold.
9. When testing is completed, disconnect pressure
gauge from the installed diagnostic fitting. Remove
diagnostic fitting from manifold and install removed plug
into manifold. Torque plug to 25 ft--lb (34 N--m).
1. Front frame 2. Rear traction manifold
Figure 41
2
1
FRONT
1. Rear t raction manifold
2. #6 zero leak plug
3. Relief(RV)valve
4. Reducing (PR) valve
Figure 42
1
2
3
4
Hydraulic
System