2240 Steering rebuild

[dcyrilc]

Here is what I have from the tech manual.

 

[dcyrilc]

Let's try this again with the correct picture.

 

[dcyrilc]

I ordered all the gaskets and seals yesterday. Should have them in about a week. Probably after Thanksgiving.

Anyone have any sugestions on how I could test the integrity of the valve seats for leakage? I don't think they leak, but I'ld prefer to check them while it's apart.

 

[RPW]

Some of your questions might be better asked in the hydraulic section.

Good luck.

 

[dcyrilc]

Here's a pic of what I found to be left of the O-rings after I took the steering housing apart. Most of my steering problems should be related to this. I'm going to have to really be careful to make sure I get all the pieces cleaned out before I put it back together.

 

[dfkrug]

Hey, Cyril...just saw your thread. Looks like you are on the right path
toward getting your steering fixed. It looks like you have found your
cause of failure (O-ring). Since a new valve shaft is hundreds of $
from JD, I would reassemble the valve as carefully as you can using all
the new parts, and keep everything super-clean. This means be careful
what kind of rags you use...leaving lint fibers behind is not good. Any
carb-friendly solvent should be OK to clean things...don't use acetone
or some of the other more aggressive solvents on rubber or plastic parts.
As for testing the final assembly, you will most likely find it much easier
and better to test it in the system, not separately. Any external testing
would likely only find external leaks. Internal leaks would not be visible.

None of my JD tractors ever had a PS problem; the only PS system I have
rebuilt (Kubota) was totally different.

I am a big fan of pressure washing BEFORE anything is opened up....its
kind of like disinfecting before you start an operation. I try to avoid
hitting things like switches and guages, however. And greasing/lubing
afterwards.

As for fitting new seals over pitting or rust, that's a tougher call. You
may have to polish up that area before final assembly.

Good luck.

 

[dcyrilc]

dfkrug, Thanks for looking!

I already ordered a new shaft as it was only $120.00. As for the valve assemblies, I think I'll try to use air to blow out the valves real good just to make sure there is no pieces of the old O-rings in there. I'll also make sure to blow out all passages in the housing thouroughly. Then reassemble and as you suggested, test in the tractor. I think I'll replace both bushings in the system while I have it open.

 

[dfkrug]

$120 is not too bad. Did you ever figure out why you had so much
end play on the steering?

 

[Gator6x4]

If there are no pits in the shaft, only discoloration a machine shop can chuck the shaft in a lathe and use "Crocus Cloth" to return the shaft to it's original shiny self. I don't think I would use "Emory Paper" on the shaft, it will leave scratches.

 

[dcyrilc]

$120 is not too bad. Did you ever figure out why you had so much
end play on the steering?

I think so. My current thought is that the O-rings leaked bad enough that I didn't get any steering responce until I had the valve body against the thrust washer at each end of the action.

The way my steering works, the steering shaft threads into the steering piston. As you turn right, thread shaft into the piston, you open the valve in the lower valve assembly, allowing high pressure fluid access to the lower side of the steering piston and allowing fluid to escape from the upper side of the piston back to the resivoir. The valve opens proportionate to how far the shaft moves downward. Fluid continues to flow until the steering shaft and valve return to a neutral position, closing the valve. The raising of the steering piston turns the steering shaft and pitman arm causing the wheels to turn right.

Turning left is just the opposite using the upper valve assembly and fluid to the top of the piston as the steering shaft rises.

The O-rings which came out in pieces were the two lowest in the assembly. I found an area in the tech manual which states that "drift is usually caused by steering valve or O-ring leakage in the circuit of the steering direction affected". (It's interesting that each time I go through the manual, I find something I missed before) I didn't drive it much before I got it home and started working on it - never out of 1st gear. While I had it in my shop, and before I removed the steering housing, I did note that it would turn right when you increased throttle. At this point, I suspect that had I driven it much, I would have found alot of drift both directions and right being more common. Close inspection of the O-rings shows the inner surface to be quite worn. The worst of which, on a cross section, have vearly 1/2 of the O-ring worn away.

I think that I had so much leakage that the valve had to be all the way open before I got enough pressure to move the steering piston. Hence, extreme right to extreme left before movement occured either direction.

Once I get the new parts and get it back together, we'll see if I'm right. The parts won't be in until sometime after Thanksgiving. Also I've decided to replace the bushings while it is apart. I'm going to have the dealer do this since I don't currently have the equipment to pull and replace them.

Everything going well, it should be back together around the end of the first week of December.

I'll keep posting here until I have the steering working the way it is suppoe to.