Test No. 6: Checking Charge Pressure - Toro Groundsmaster 455-D Service Manual

TEST NO. 6: Checking Charge Pressure

1. Make sure hydraulic oil is at normal operating tem­
perature by operating machine for approximately 10
minutes.
2. Lower cutting units, engage parking brake and stop
the engine.
3. Install a 1,000 PSI gauge onto the charge pressure
quick disconnect fitting.
1
4. Start the engine and position throttle at high idle
(3000 RPM).
+25
TESTER READING TO BE 100 / PSI.
–10
Figure 15
5. If pressure is low, inspect charge relief valve and
valve seat.
1. Charge pressure test port
6. Also take a gauge reading while operating the ma­
chine in forward and reverse. Start the engine and put
the throttle at full engine RPM. Apply the brakes and
push the traction pedal forward, then reverse. If pres­
sure is good under no load, but drops below specifica­
tion when under traction load, the piston pump and/or
motor should be suspected of wear and inefficiency.
When the pump and/or motor is worn or damaged the
charge pump may not able to keep up with the internal
leakage.
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Groundsmaster 455-D Page 4 - 25 Rev. C Testing