Hydralic valve banks

[pfilips]

I attach a very large JD backhoe on to my 7120 international. (this hoe was originally on a construction tractor and now is made to fit 3 point. It has two hoses. And will dig any thing but from time to time the hydralics will completely lock up and oil will boil out of the top of the valve bank just like if you hook the hoses up backwards. The only way to get it to work again is to put the tractor in float and take all the pressure off the hoe valves( Hoe has a seperate seat and valve bank to run the hoe). I do notice that the bucket valve is very hard to move when this happens. Tractor hydralics are fine problem is in the hoes valve bank. Any help is greatly appreciated.

 

[kennyd]

Welcome to TBN

It sounds like it might be some kind of pressure relief valve? Is there one spot in particular that the fluid comes from?
Pictures would maybe help us help you...

 

[RickB]

Replace the male tip on the return hose. And possibly connect the return oil hose to a low- or zero-pressure return. You may have to talk to a knowledgeable dealer to explain to you where to install the zero pressure return fitting, but if replacing the tip doesn't help, that would be my next move.

 

[pfilips]

Welcome to TBN

It sounds like it might be some kind of pressure relief valve? Is there one spot in particular that the fluid comes from?
Pictures would maybe help us help you...

Kenny
Oil pours out of the top of the whole bank all 6 valves mostly from around the spool from under the dust covers. After it locks up only one valve is hard to move and that is the # 5 valve which controls the bucket. but as soon as all pressure is off including the outriggers it will work fine again. When I say locks up none of the valves work and sometimes the hoe will want to move in directions regardless of were the valves are
pfilips

 

[RickB]

Kenny
Oil pours out of the top of the whole bank all 6 valves mostly from around the spool from under the dust covers.
pfilips

That's a clear indication of excessive pressure in the return circuit. If it continues to leak after the cause is cured, remove and straighten the spool seal retainers and replace the spool seals if they are damaged.

 

[pfilips]

Thanks Rick

I think you are right on the return line as soon as the ground softens a little bit I will hook directly back to the resaviour and I know my problems will be over
pfilips