534D-6 Gradall won't steer

[Bullseye Beaver F.]

534D-6 Gradall won't steer properly. Have to use two hands to steer it, and that is a chore. No fluid leaks. Please help me troubleshoot. Thank you.

 

[lantraxco]

Don't know the machine, but I think you've lost the power steering hydraulic pressure and you're now steering on the emergency function. Check hydraulic fluid levels, look for possibly a belt driven power steering pump, though I doubt it's belt driven. Beyond that it's time for hydraulic schematic and gauges, hopefully somebody here can help on the schematic. Might be a flow divider or a gear pump or pump section failed.

 

[tool_king]

Whats you email ? I can send schematic on it ? Do all other functions like boom ,tele and fork tilt ?

 

[Bullseye Beaver F.]

Whats you email ? I can send schematic on it ? Do all other functions like boom ,tele and fork tilt ?

 

[Bullseye Beaver F.]

Yes, they all work. I had to change the hose that runs the boom a few weeks ago. The men said it started to get hard to steer sometime after that to the point where it is now.

 

[lantraxco]

Looks like a single pump for brakes and steering, so the pump could be weak, the brake flow divider may be malfunctioning, the steering flow divider may be malfunctioning, or the steering relief valve?

 

[Bullseye Beaver F.]

Thanks for your reply. I am leaning towards the steering relief valve, also. Will check on that first.

 

[tool_king]

Thanks for your reply. I am leaning towards the steering relief valve, also. Will check on that first.

If you would like the manuals on it .Let know your email and I will send them to you.

 

[Bullseye Beaver F.]

Thank you. I have some manuals but they don't show the steering relief valve.

 

[tool_king]

Thank you. I have some manuals but they don't show the steering relief valve.

Whats your email ? I will send the manuals to you .

 

[Bullseye Beaver F.]

steven.flaig@aol.com

 

[Bullseye Beaver F.]

Here's an update on the 534 d gradall I've been working on. I still haven't got it to steer. When you jack it up you could turn the wheels with the steering wheel. But when I let the Jack down it wouldn't steer any more. No visible pinches, kinks, etc on anything. I changed the steering control unit. No help. changed the hydraulic pump that bolts into the engine block most of the things go to the steering on that. I took the priority flow control valve apart it was free and clear I checked the flow divider valve and it was free and clear. I unhooked the steering cylinder on one side. still wouldn't steer. Thanks in advance for any further advice.

 

[tool_king]

Here's an update on the 534 d gradall I've been working on. I still haven't got it to steer. When you jack it up you could turn the wheels with the steering wheel. But when I let the Jack down it wouldn't steer any more. No visible pinches, kinks, etc on anything. I changed the steering control unit. No help. changed the hydraulic pump that bolts into the engine block most of the things go to the steering on that. I took the priority flow control valve apart it was free and clear I checked the flow divider valve and it was free and clear. I unhooked the steering cylinder on one side. still wouldn't steer. Thanks in advance for any further advice.

You probably have something bypassing for sure.

 

[Bullseye Beaver F.]

Still won't steer unless I jack up the whole steering part in the rear end and then you can steer with no pressure on the wheels. Any weight on it and it won't steer. On your comment, what would the "something" bypassing be?

 

[lantraxco]

Need to tee into the pressure line to the steering unit, put a gauge on her. Sounds to me like you got zero or near zero pressure supply.

 

[Bullseye Beaver F.]

Ok. I did that and there is no pressure.

 

[Bullseye Beaver F.]

Correction. I have 200 pounds of pressure.

 

[Bullseye Beaver F.]

Am I missing something when I check the valves?

 

[lantraxco]

Hmm, looking at the schematic, you may have to engage the steering to get a proper pressure reading? It probably flows through to tank so you're only getting backpressure from restriction. Should go up close to the 2,500 psi relief pressure if you hold the wheel hard against the steering.

Does the sway cylinder work properly? That looks like the function the excess steering flow goes to.

 

[Bullseye Beaver F.]

I did engage the steering, held pressure against it, (had a man do it while I checked the pressure). Only 200 pounds. The sway cylinder works, but I will check to see if properly.
Thank you so very much for your help on this problem!! I was also thinking if the gears in what drives the pump could be failing.