3400 Ford Power Steering Question

[Craig Kruse]

I notice my power steering is harder than I think it should be and I found that my steering shaft goes up and down a little bit when I turn from left to right and vice versa. The question is - is the steering shaft supposed to go up and down slightly when turning. My manual says it travels axialy but I'm not sure what that means. Is axialy equivelent to verticle? Oops that's two questions.
 

[Sean in PA]

It should go up and down very very slightly. So slightly that it should almost be unnoticeable. The up and down movement is what actuates the control valve that directs the hydraulic fluid to the cylinders for the hydraulic assist, but if it is moving up and down to where it is noticeable to you, then the upper thrust bearing is likely worn to the point that the whole shaft is moving up and down, including the control valve housing, so the control valve is not working as it should.
 

[Craig Kruse]

[Ultradog MN]

The upper and lower thrust bearing almost never go bad on a PS unit as they are constantly bathed in oil.
I'll bet you dollars to doughnuts that you either forgot or improperly swedged the upper nut
to the shaft and it loosened on you.
 

[Craig Kruse]

[Ultradog MN]

Yeah, the worst part about it is pulling the tin off again.
If it were me and I was that far into it I would go ahead and pull the hydraulic block out of it and go through it. Take it apart and clean the rust and crud out of it. I like to wash fine parts like that in lacquer thinner then lightly grease and reassemble. Replace the lower seal while you are in there and both of the Orings - part #s 14 and 33 in the photo below.
Make sure you clearly mark the lines to the cylinders at they can be a pia to sort out if you don't. I use tape and mark them top and bottom.
Be careful not to drop the little springs and plungers in the hyd block as you pull it off the column. They will want to fall out the bottom.
I&T FO-31 manual has a pretty good description of adjusting the spring washer and swedging the nut.
If you get into trouble reinstalling the plungers, etc in the right holes just holler.
We can help.


 

[Jetbird]

Craig, I rebuilt the steering box on my 68 3400. Mine had a broken washer under the nut that is staked to the shaft (#20 in nh parts drawing, they call it a "control valve bearing preload spring"). I think the nut was loose also. You can look up my post on the subject, it may help. My steering wheel had a lot of free play in it, and if I turned the wheel left I think the wheel lifted up towards me. Let the wheel go and it would spin the other way and fall back down on its own. It seems to me that the control valve bearing preload spring is the weak link in this steering box once power assist is lost. The spring is certainly weaker than the tapered roller bearings that stabilize the steering shaft axially (up and down) in the manual steering box. If the power assist is working, the spring doesn't endure much load since the pistons are pushing the wheels back and forth. Once assist is lost, the washer takes a lot of axial force. If yours is broken, the pieces could be loose in your system and could kill your ps pump. I think that is what gouged the body of my ps pump and rendered it useless. Good luck and post back. Oh, and by the way I sympathize. I bought my 3400 for $2600 last July and thought I stole it. Now I have put about $1500 in parts and many many hours into it. Strained relations with the wife, but the tractor finally works and I learned a lot and feel good about bringing it back to life. Don't despair. But if I may suggest, you may want to do something nice for your wife, she probably envies all the attention the "other woman" is getting.
 

[Craig Kruse]

[Jetbird]

Craig, I totally sympathize. I do stupid crap like that all the time. One thing I have going for me though: I am too damn stubborn to give up! Good on ya for figuring it out!