3000 - Troubleshooting power steering (right turn diffic

[supton]

I have a 1970 Ford 3000 I purchased a few months ago. Upon purchasing I replaced the filter in the power steering pump and replaced the steering shaft seal, as fluid was almost pouring out of the column. I only went down to the shaft seal and didn't remove valve assembly or anything else. When I got everything back together, the power steering worked perfectly when turning left and right.

However several weeks ago the power steering stopped functioning when turning right. Its basically like manual steering, yet left turns have full power steering. If I jack up the front end with the engine running, the left turns fine, but there is some resistance turning right (but much easier since wheels are off the ground).

Further, with the engine off and the wheels off the ground, I can grab hold the right tire and turn it fully out. Yet I cannot turn it back straight without using the steering wheel.

How would I troubleshoot this? Something with the control valve? While I didn't go wild, I did have to bang on the steering wheel and eventually cut it off when replacing that shaft seal. I'm hoping in this process, I didn't weaken something to where it gave out a few weeks later.

Thoughts?

This post was edited by supton on 06/20/2022 at 03:50 pm.

 

[Ultradog MN]

I'm thinking it is in the control valve.
Likely a broken spring. But I have seen
them with rust and crud in them so they
didn't work too.
You will need to back into it.
This time you will want to replace the
lower seal while you are in there. #14 in
the photo below. Also replace the two
Orings #33.
Mark the 4 Lines that go from the valve to
the cylinders before you remove them!!
It is a PIA figuring them out if you don't.
Take CARE when you pull the valve off the
column so all the little plungers, balls
and springs don't fall out the bottom and
drop all over the floor.
Is not a complicated job but if you want me
to talk you through it you can call.
I have helped a few guys with this.
Jerry
612 - nine six eight - five two 4 8

 

[supton]

Sorry....been out of town.

Thanks for the response. I'm also speculating that since this happened shortly after I changed out a very nasty filter in the power steering pump, then maybe some crud got sucked into the valve (hence supporting your rust/crud comment).

While not wanting to rip into this again, it looks like I'll have to. Thanks for the heads up about the o-rings. I was planning on replacing that anyways, but didn't know there were two in there.

I probably won't tackle this for another few weeks, but if I do run into issues, I'll reach out. Thanks again.

 

[supton]

Pulled everything apart tonight, replaced the lower seal, both o-rings and inspected everything. The only thing slightly off was the valve with the balls was a little stiff but after some cleaning it was much better. As for the other valves, no broken springs or corrosion to speak of. After giving everything a cleaning, I reassembled and started the tractor back up. Unfortunately same issue. Turns left fine, but no power steering when turning right.

Kinda wishing I blew some air through valve block in case there was any debris but then I would have probably sent some unseen part across the barn.

Beyond this, the only thing I can think of is the power steering cylinder and but neither are showing any visual signs of problems or leakage. Before investing any more money into this, I'll thinking of disconnecting both cylinders and see if they move freely. Plus while I'm at it, I'll jack up the tractor again with the cylinders disconnected and grab the tires again to see if they still have problems turning.

 

[supton]

Here is the update. The steering hydraulic cylinders are definitely good and I went ahead with replacing the axle spindle bearings while I was at it. With the cylinders disconnected, the wheels turn freely when jacked up.

After this, I took apart the steering valve assembly again, blew out all the passages, reassembled and still have the right turn issue. I've also was sure to back off locking nut slightly above the valve assembly so the shaft can travel up/down freely.

As for what I'm noticing with the valve assembly, the plungers raise up when I turn the steering wheel left, but about when the wheels are straight, the plungers are flush with the top of the valve plate. When I turn right, they don't recess or do anything. This doesn't seem right, as I'd assume that these would go down to move the flow to the right cylinder. Maybe I'm wrong but I don't have another system to compare it too.

Any other suggestions would be greatly appreciated.

 

[supton]

Well finally found the issue. The lower bearing (#86512848) on the shaft was split and bearing were scattered all over the place in the steering gearbox.
Basically with the bearing casing be split, it slide sideways and kept the steering shaft from traveling down all the ways. So beside making it hard to turn, this also prevented the plungers within the valve from traveling down, and thus kept the hydraulic cylinders from functioning properly.
For anybody who may have this problem in the future, take note of the gearbox cross-sectional diagram in the shop manual. It is possible to remove and reinsert the steering shaft without removing the sector gears. To get the shaft teeth to align correctly with the sector gear, I had the front of the tractor jacked up and turn the wheels all the way to the right. Then you have to work the shaft in carefully, getting the first gear tooth past one of the sector gear teeth and the end of the shaft in the bearing (be careful as it may take some time). After you get this, "slowly" nudge the wheel from the far right position towards center. Be very careful doing this, because if the steering shaft isn't aligned into the lower bearing, then you could ruin the bearing.

This post was edited by supton on 07/27/2022 at 07:45 pm.

 

[Sean in PA]

Glad you got it licked, and thanks for posting back with the final cause and resolution.