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Old 01-10-2016, 10:50 PM
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Default Re: PC1800 Front Shovel (1/12)

Interesting?!?! Have you confirmed the volume of oil being supplied by the pump? Disconnect the return line at the tank and put a container that is calibrated or that you can measure the actual quantity easily. Depending on how large your reservoir is, run the pump without actuating any circuits and measure the amount returned. May have to run for only 15 or 30 seconds, but confirm pump delivery. What pressure is being displayed during this test? Confirm system maximum pressure will make 275 PSI. Bottom a cylinder (either direction) by fully stroking control valve and see if relief valve actually is 275 PSI. Also, at this condition, return oil volume should match max output of pump. (You may see a slight decrease if the motor reduces RPM while under relief pressure, plus no pump is 100% efficient. Most big gear pumps can be up to 98% efficient when new. I'm guessing yours should be near that.) When you saw the system operate at 210 PSI, was that while cylinders were actually moving? Should go to 275 PSI when cylinder hits end of stroke. If there is a question about individual circuit flow, disconnect a cylinder line and put it into a container for measuring. Stroke valve fully and measure volume delivered to circuit. At same time, see if any oil is being returned via the valve return to tank. Should be practically nothing. If is significant amount, the valve may have something going goofy. Also, observe system pressure at this condition.

Ken
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