I have a cavitation noise or squeal coming from supply line to the back hoe. I've been reading and saw some reference to a power beyond valve and a screen in the loader valve body. Where exactly is this located or does this not apply to my model?
There is no power beyond valve, rather a sleeve with orings on it to direct the oil out a fitting to the downstream valve. this is the power beyond circuit. It is unusual for a PB oring to blow but it is an item to check if the hoe suddenly loses power. it is the fitting where the hose comes out of the inside fitting on the valve and the last part to be removed. Symptom of a blown PB oring would be slow and a drastic loss of digging power in the hoe. If the pressure reads lower on a hoe/ loader comparisom likely the ring is gone. The loader control valve contains a poppet behind the relief valve cartridge with a screen that rarely but can plug with debris and shut the system down. If your squeal occours when the hoe is at the end of its capacity that is normal relief valve sounds, if it does it without loading the hydraulics that's another matter entirely . give us more details. a cavitation type noise can be caused by low oil in the reservoir , an intake leak into the pump inlet or cheap oil that does not get rid of its air as it circulates