question Zetor 8011 - how to adjust the steering pressure release valve

I am working on a friends 8011 . Does anyone know how to adjust the steering pressure release valve? The power steering on this machine
works when it is cold, but as it warms up the steering has very little assist. I assumed the pump was worn. But when I took it apart there was no wear inside at all. I suspect the release valve may be the reason.

Can you upload a photo ov the release valve please?

Most valves I know from Zetor/ZTS have 2 possible ways to adjust:
- with washers under a spring
- can be adjusted by turning it so that the spring becomes tighter or looser

I wouldnt tinker too much with the steering housing, they all go bad and sour. 20 years ago the price for a rebuilt steering housing was 600 Euro, an orbitrol conversion kit costs less than that today.

Orbitrol conversion is pretty simple on an 8011, there are kits for this purpose. The orbitrol has a built in pressure valve so you can bypass the one in the powersteering tank.

I set up the steering oil tank on a bench and connected a pressure gauge. There is no easy place to connect the gauge so I took the valve out of the tank and drilled a hole in the top and welded a fitting on top for the gauge. When I checked the pressure it was set far too high. I backed it off to 8MPA. Then reassembled the system to the tractor. When I ran it with the gauge still on the system, there was assist to the left only.
I pulled the steering assembly apart and there was a metal chip stuck in the spool valve, preventing it from moving. The steering assembly is not that complicated but it does require a lot of time and patience.

Big problems can sometimes be cheap to fix