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Got the petrol running but the hydraulics are stuck

Posted: Sat Jun 29, 2013 4:48 am
by pjjms
Had some spare time at last so put the engine back in. I overhauled it some time back because it had no compression and knocked badly. Runs good now but I can't get the hydraulics to lower regardless of the lift control position. No movement at all. The tractor has been sitting for 12 years so I suspect it is just seized. But before I dive into it... This one has the flow control with a link to the lift control. The link is disconnected and the flow control seized, as is the aux/lift selector knob. Would any of these controls stop the arms going down?

Re: Got the petrol running but the hydraulics are stuck

Posted: Sat Jun 29, 2013 2:11 pm
by Brian
No, you have a stuck unload valve. Remove the lift, take off the control valve spring holder at the front of the ram cylinder and draw the plug out. Gently tap or push the unload valve out and polish it with metal polish. Do not use any form of abrasive like emery paper on the valve.

Image

This is what you will find.

If you are lucky you will have a steel ring on the valve but if you have an "O" ring only replace it with one fron Case New Holland as they were a special rubber compound. Alternativly you can leave the "O" ring off altogether. This works if you have sticking problems in work.

Re: Got the petrol running but the hydraulics are stuck

Posted: Sun Jun 30, 2013 3:50 am
by pjjms
Thanks Brian

Re: Got the petrol running but the hydraulics are stuck

Posted: Sun Jun 30, 2013 10:23 am
by Brian
Bit under the weather so my thinking was not up to scratch. You said the Auxiliary service valve was also seized, if it is seized in the "Out" position it will not allow the lift to drop. If this is so, you should hear her "dead-heading" if you raise the main control lever with nothing on the Auxiliary outlet (Trailer Tipping Pipe).

Picture is of a Super Major but that bit is the same on Dextas.