Post in 'The Gear' started by bruce56bb, Jan 6, 2006.
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Take your relief valve apart and make sure the spring is not broken inside. (very common) Take note of the measurement of the adjustment locknut also. (for setting it back without a gauge)
If you have a pressure gauge installed, loosen the locknut on the relief and double check your relief setting. (when it relieves it makes a high pitched screech) Double check your mfg's reccomended settings.
If the relief valve is okay, put a hard piece of wood and scrunch down on it (just enough to build pressure up) and put the valve to nuetral. This should lock pressure to one side of the Hyd Cyl. Look at the gauge- does it drift down quickly? does the rod physically move the opposite way? if it does, the piston seals are bypassing.
For the cost of having a Hyd shop rebuild that cylinder you can buy a brand new one from Northern Handyman. or hercules hydraulics
Take these dimensions:
pin sizes (diameter)
cylinder outside diameter
pin center to pin center fully extended
pin center to pin center fully retracted
Working pressure of system
any numbers stamped on cylinder barrell
Take these with you to Northern and have them get you a comparable cylinder.
As far as your pump goes, it looks like a gear pump from the pictures. they usually leak externally and/or raise hell when they go bad. I would check the above first though.
(I was a Hyd Tech for Caterpillar for 7 years)
woody,there isn't a gauge on it. if i would put one on it, where do i put it at? also, in my pump picture, what is the fitting(plug?)that screws in on the left side of the pump? is that the relief valve?
also,the pump is starting to leak now from where the input shaft goes in.
You should put the gauge between the valve block and the cylinder end port of the hydraulic cylinder. If the cylinder port and hose fittings are pipe thread, and of course it doesnt look like it will get busted off the first time you use it, you can get a pipe tee for the hose port and gauge and rig it up right at the cylinder port. (hose into tee w/gauge into cyl port)
As far as the pump, without knowing the model and make, I can only guess. If it has a lock wire on it or some kind of locking device on an adjustable screw, it can either indeed be a relief or a flow adjustment.
Most relief valves are on the valve block where they can vent back thru the valve back to the tank.
See if you can find a label on the pump and I'll see if I can get some info for you.
Is the pump on this page? http://www.princehyd.com/default.aspx?tabid=41
Also, as far as fluid type goes, unless the Mfg says otherwise, 10 weight is standard on most heavy equip applications. Running different type fluids could soften seals and cause leaks.
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