Backhoe ford 555 steering problem. steering motor?

[x2305]

I have a ford 555 backhoe and the power steering turns fine to the right, but when I turn left the wheels are jumpy and there is a noise (tapping or pulsating) under the dash in the steering motor.
If I turn the steering wheel fast sometimes it just spins and won't turn the wheels at all going left. but if I go slow it works ok. Also sometimes after I turn right and let go it will turn left all by itself and jumpy too.
I have enough fluid in it and there is a slight leak in the left cylinder. I tried bleeding it by going to each end back and forth. Could the steering motor be the problem? What is an orbital?

 

[berky]

sounds like the steering motor is bad. Or may have a check/unloading valve in the motor that is not working properly. time for a rebuild or a new one.

 

[x2305]

How can I tell for sure that it is the motor and not steering cylinder. the left cylinder is leaking a little, could it have air in the system somewhere ? Would I be better off rebuilding the motor or buying another one? I would like to make sure it is bled before I buy a motor.
Like I said going right is ok and the problem is in the left circuit, could the motor only go bad on one side?

 

[RickB]

Replacing the most expensive component in any system before troubleshooting is a fool's errand and giving advise to do so is ignorant.
There is a systematic approach to troubleshooting this steering system, and step one involves a service manual.

 

[x2305]

I have the service manual. I read it, not every word but pretty much most of the steering hydraulic system. I did not see a troubleshooting part on how to determine what part is the problem.Am I missing something.? The manual tells you how to remove and rebuild the motor. How can I get instructions on how to trouble shoot the system. If I can determine the bad part I will change or rebuild it. I agree I don't want to buy the most expensive part if I don't have to. What goes bad in the motors--seals, orings ?

 

[RickB]

There's a section in the manual that details pressure tests, etc.
When was the last time the steering filter was changed?
Invest some time in reading the manual.

 

[x2305]

the filter was changed a few months ago by previous owner. He said ever since he changed it , it started doing this. He said it was air in the system. It won't bleed. Could he have put the filter in wrong? I may pull the pump and look at the filter.

 

[aircommuter]

Start by checking the pump pressure on the engine, it should be around 1600 psi.

 

[x2305]

I checked the pressure at a wheel cylinder. With wheels off the ground turning left the pressure is constant 1400 psi. even when it hits the stop. Turning right the pressure is 250 psi all the way and is still jumpy. I grabbed the tire at stop position and it went to 1400 psi. I think the pressure should be about 200 until it hits the stop then go to the relief. I understand the relief is a little low (should be 1550-1650) but I think the pump is working because it is making pressure. I know I can shim up the relief , but will it help? Now I am think there is air in one or both cylinders or there is blow-by in the cylinder. With the engine off I can push on the tire and it is spongy and moves about 1-2 inches before it gets hard. Is this air? Any help will be appreciated.