IH 454, relief valve

[Big Red 454]

What are the signs of a bad relief valve?

 

[used red MN]

Big Red, please keep in mind when you post here you
and your tractor are not the only items we are focusing
on. And we are not walking up and looking at the
machine to be reminded of the problem it has. I
remember you your previous post about your 454
hydraulics but not everyone is viewing on here daily.
So your question alone without any background info
has multiple answers, even though you post as 454 we
cannot always assume that is the tractor you are
having the problem with. I will link your previous post. I
cannot help with your problem. All sorts of dumb
things have happened. Any chance a rag may be
floating around in the system getting sucked up on the
filter screen?
Previous post on IH 454 hydraulic problem

 

[caterpillar guy]

Usually it is low working pressure though it could also be high depending on what happened in the system. If the internal body is scored and not flowing like it should it could go either way high or low. If the spring broke it would most likely be a low pressure sign. If dirt got into it it could get stuck and be either way high or low. So lots of reasons for high or low pressure from a relief valve. Leaking suction line or tube in the case could also cause low pressure or no pressure/ flow at all. A leaking o-ring could cause low or no pressure also.

 

[Big Red 454]

I had this same issue before replacing the pump and the fluid / filters . Something is causing presure to the loader valve to drop off drastically without affecting 3 point, pto,steering. How could you check the suction tube and where is it located? If it was the tube would you not loose hydraulic function from everything? Thanks