Toro Groundsmaster 4500-D Series Service Manual page 156

Procedure for Reverse Traction Circuit Reducing Valve (PR) Pressure Test
Hydraulic System: Testing
Note: When in reverse, pressure reducing valve (PR) limits the pressure to the
rear axle motor to 31 bar (450 PSI) so the rear wheels will not scuff the turf.
Prevent personal injury and/or damage to equipment. Read all
WARNINGS, CAUTIONS and Precautions for Hydraulic Testing at the
beginning of this section.
1. Make sure hydraulic oil is at normal operating temperature by operating
the machine for 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 traction manifold is a zero
leak plug that has a tapered sealing 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 removal with less chance of
damage to the socket head of the plug.
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1. Front frame
3. Locate rear traction manifold that is attached to the front frame next to the
left side front wheel
rear traction manifold and install diagnostic fitting (Toro part number 59-7410)
into manifold port.
4. Connect a 70 bar (1000 PSI) pressure gauge with hydraulic hose attached
to installed diagnostic fitting.
5. Start engine and increase engine speed to high idle speed. Make sure that
Auto/LOW mode 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 29 to 32 bar (420 to 470 PSI) when the pressure
reducing (PR) valve opens.
CAUTION
Figure 65
2. Rear traction manifold
(Figure 65). Remove #6 zero leak plug on the inside of
Page 5–54 Groundsmaster ® 4500-D/4700-D
19245SL Rev A