Oliver 550 hydraulics

[R&JW]

I have a 1961 Oliver 550 with a loader on it.
Loader valve gets oil supplied from a block off of the front right side of 3pth lift cover.
My hydraulics run very hot all the time, but everything works as it should.
I have since found out the return oil from the loader going back to the tractor via the block on lift cover has approximately 1500 psi back pressure.
What is under the lift cover that can be restricting the return oil?

 

[rrlund]

If the valve is in the neutral position, the return pressure should be the same as the output pressure shouldn't it? It's an open center valve, so the oil is just passing through the valve and right back to the tractor. Unless I'm not understanding what you're saying?

 

[R&JW]

It seems like the oil returning into the tractor has an internal restriction.
3 pth control valve is working ok.
My thought is that if the 3pth control valve is in neutral or lower position, there should be very little restriction on returning oil.

 

[R&JW]

Does anyone have an schematic drawing of the hydraulics for this tractor.