790 lift limit - hydraulic relief valve

jd790rf · Aug 6, 2008

Just a quick question - If you try to lift something too heavy and exceed the 815 lbs lift on a 790, is there something that would divert the pressure and protect the tractor? I kind of thought there was a relief valve that would cut in; make a noise (at least on a Ford) and no damage would be done....it simply wouldn't lift the implement? Anyone know if there is a built-in safety guard of this type that saves the tractor itself by diverting the fluid around the load?

thanks for any replies.

Willl · Aug 6, 2008

jd790rf said:
is there something that would divert the pressure and protect the tractor?

I don't know of a tractor that 'doesn't' have a main system pressure relief valve.

On the 790, it's set at 2050 PSI

kennyd · Aug 7, 2008

Yes, your tractor has a relief valve. There have been a few people who have raised the pressure so they can lift more. There are quite a few post's about the procedure from about 2 or 3 years ago.

Are you experiencing a problem that prompted you to ask the question?

jd790rf · Aug 7, 2008

Well,

I thought so when I tried to lift a King Kutter 2 5' tiller; but it was ultimately my dumb mistake. The tiller was raised up and down a couple times; I thought success!
It wasn't too heavy after-all. Then I tightened the valve to slow the drop on the pto equipment a little too tight and all of sudden the tiller wouldn't raise again. 15 minutes later after feelings of disaster and a strange sound when I tried to raise the tiller again; I realized what I might have done, opened the valve and the tiller would raise again. But then it just occured to me to ask and make sure there was a safety mechanism to keep tractor from being damaged by this type of thing in the future. Shipping said tiller was 690lbs but I never knew how much of that was packaging.