I was thinking these trucks had a belt driven dedicated steer pump. But i could be wrong. I did some work on one a few years back that had a bolt on as i described but it could have been like a 5 ton model. A real **** to change out best i can remember.
I am sorry I do not have serial numbers right now as it is still in the warehouse I purchased it from we will be bringing here next week just wanted to see if there was anything that is notorious on those for the steering. Thanks for all your help guys I appreciate it.
a serial number would help somewhat
but as steering systems go you'll need to check the pressure with a guage at the auxillary section of the control valve. This is where it gets it's oil from.
Sure the priority valve might be sticking but isolating the problem should be your main priority, the only way your going to achieve this is to check pressures at specific points-.
- control valve auxillary output
- orbital valve pressure out ports
- at the steering cylinder (pulling each line and checking for bypass flow)
You can start at the control valve then follow the circuit till you locate the pressure loss.
Steering pressure should be about 1400psi at the test port on the control valve. (since we have no serial number this is just an educated guess based on that class of truck)
you can also pull the priority valve out and take it apart and clean it... since the truck was sitting for an extended period of time it may just be stuck.
I did look for a ps pump and did not see one so I will check the priority valve next and see. I am pretty sure that the steering was working on it when it was parked 7 months ago. Is there a check valve anywhere that may be stuck just dumping the pressure back in to the tank?
Like BB says. The orbitrol beneath the steering hand wheel will probably have 4 lines. One each to both sides of steer cylinder , one low pressure hose the ends up dumping back to tank and then the pressure line you are looking for. It will either go to the main hydraulic valve, a priority valve or the pump (it could have a dedicated ps pump).
I've never worked on your exact model, but I have had steering issues on smaller Yales & if it steers at all (with no power assist) it's been a problem in the hydraulic control valve. On smaller Yales the power assist comes from the control valve-I'd trace the hosing to see if yours is set up the same way.
I felt like popeye after I got done moving it but it does turn just not with power. That was with weight on it.
If there's weight on the steer axle, can you muscle the steering wheel to turn the wheels, or is there no reaction at all with weight? I'm thinking maybe the steer cyl needs service.
could the priority valve be stuck not allowing fluid to go to the orbital.
the steering works just no power.
if you lift the back of the counter weight off the ground and the engine off, can you steer the wheels from left to right?
A model and SN would help. Locate the main hydraulic pump. It's going to have a large suction hose from the tank attached to it and at least one smaller hose leaving it going to to the main hydraulic valve OR a flow divider/ priority valve. If there are three lines at the pump, the smallest probably feeds the steering orbitrol valve, and the pump would have a priority valve inside of it.