IMPORTANT: Test ports on the transaxle are painted closed. Opening the ports will loosen the paint. Make sure dirt or paint particles do not fall into the open port.

Charge Pressure Test

NOTE: See Sauer–Sundstrand IHT Service Manual for more information.

Use a 500 or 1,000 PSI (35 or 70 Bar) test gauge.

Specification: 80 to 130 PSI (5.5 to 9 Bar)

1.Make sure hydraulic oil is at normal operating temper- ature by operating the machine for approximately 10 minutes.

2.Lower cutting unit, engage parking brake and stop the engine.

3.Remove the plug from the charge pressure port and install a 500 or 1,000 PSI (35 or 70 Bar) pressure gauge with extension hose.

4.Start the engine and move the throttle control all the way forward. Take pressure reading with machine sta­ tionary. Also take a pressure reading while operating the machine in forward and reverse. To test in forward and reverse, engage the brakes and push the traction pedal forward, then reverse.

NOTE: When you move the traction pedal to create pressure, move it a short distance first and wait for a change in sound before moving the pedal further. The change in sound indicates that the easy ride valves have closed.

If pressure is good under no load, but drops below speci­ fication when under traction load, the piston pump and motor should be suspected of wear and inefficiency. When the pump and/or motor is worn or damaged the charge pump is not able to supply enough oil to keep up with internal leakage in the closed loop circuit.

Charge Pressure Priority Valve Test

While checking charge pressure, check the the opera­ tion of the charge priority valve. Rotate the steering wheel to create back–pressure while observing the gauge. The gauge should not have a significant pres­ sure increase during steering operation.

1

Figure 11

1. Charge pressure port

Hydraulic System

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Groundsmaster 3000/3000–D

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Image 82
Toro 3000D manual Charge Pressure Test, Charge Pressure Priority Valve Test