Toro Groundsmaster 4500-D Series Service Manual page 150

Procedure for Traction Circuit Charge Pressure Test (continued)
Hydraulic System: Testing
Note: Steering and lift/lower circuits would also be affected if the third
gear pump section is worn or damaged.
9. Next, with the pressure gauge still connected to the diagnostic test fitting,
monitor the gauge reading while operating the machine in forward and
reverse. Start the engine and increase engine speed to high idle speed.
Apply the brakes and push the traction pedal forward, then reverse.
GAUGE READING TO BE within 20% of no-load charge pressure measured
in step 4 above (e.g. if charge pressure in step 6 is 18 bar (260 PSI), charge
pressure in forward or reverse should be from 13.8 to 18 bar (200 to 260 PSI).
10. If charge pressure is good under no load (step 6), but drops below
specification when under traction load (step 9), the piston (traction) pump,
front wheel motors and/or rear axle motor should be suspected of wear and
in efficiency. When the pump and/or traction motor(s) are worn or damaged,
the charge pump is not able to keep up with internal leakage in traction circuit
components.
11. When testing is completed, disconnect pressure gauge from diagnostic test
fitting. Remove diagnostic test fitting from piston (traction) pump. Install
plug into piston pump port and torque plug to 43 N·m (32 ft-lb). Lower and
secure hood.
Page 5–48 Groundsmaster ® 4500-D/4700-D
19245SL Rev A