Ford 3400 Power Steering Leak at Shim.

BlueCollar84

New User
Bought a 1975 ford 3400 with loader a short while back. Has a couple little issues that the old timer I bought it from just seemed to have just dealt with. Picking them off as I can. Next on my list is the power steering gear box. I have a leak at the shim. # 22 in the photo. Everything above it is dry and there is fluid at this point and below. My question is is it just the shim or is there potential for something internally leaking above and that is where the fluid comes out? Not sure if fluid should be in the area of the shim normally. I have some manuals and my plan was to drain fluid and disassemble to the point I can clear the shim from the studs clean everything and reinstall new shim with gasket sealer. Wanted suggestions on other possible causes for leak to address while doing this. Also it appears regular power steering fluid has been used, should I be using 134D? Not sure if just using correct fluid may fix the leak issue 134d possibly being thicker than the regular power steering fluid. Thanks in advance.
 
Your photo did not load, so I included a link below to it.

If you have oil leaking past the shim, it means your lower box is being flooded by a leak from the control valve area, specifically a leaking
seal #14. The box will have to be partially disassembled to replace this seal.

As for fluid type, 134D is the factory specified oil, although many people use automotive type PS fluid, and it won't hurt anything.
PS box image
 
Bern.
Thank you for the reply. If the looking into the gearbox I ve done so far this seal can be replaced without having to pull the entire assembly? Or am I better off just getting into it now and giving it a bit more attention while I m at it. I have the IT manual which seems to have pretty clear info on the gearbox. The tractor has a couple other small leaks however this one bugs me and makes quite a mess. Looks like I ll a small project when the part comes in.
 
You don't need to remove the entire box to replace the seal. You first remove the steering wheel (could be the most difficult part of the
job), then remove the rear hood, then part #34, then part #23, and finally part #12, which contains seal #14.

Since you say that you have the IT manual for the tractor, follow the instructions very carefully, especially with regards to the positioning
of the nut #21.
 
Bern is correct. My first guess is that
lower seal is leaking and pushing oil
into the bottom of the box.
I'll even take it a step further and will
bet the PO removed the little vent #18
and replaced it with a pipe plug. That's
the first place they leak when the seal
goes bad.
I would go ahead and pull the whole
column off the tractor though. So you can
dump the old oil out. The bottom end of
the box should use 90w.
 
Thank to both of you for your help. I ve decided to go with a Steering shaft repair kit from this site. Comes with sleeve for shaft along with #35 seal and #33 o-ring. Appears this has been an issue since there s a kit. I ll feel better having it if I do need the sleeve. Will also order #14 seal and another #33 o-ring. Will also replace steering shaft bushing as advised in the IT manual. As far as the #18 vent, it appears to no longer be serviced. I will take a look once I m into it and hope it hasn t been replaced with a plug, if it has I ll have to figure something out at that point. Will be a bit but will follow up once it s complete. Wait for parts to be on hand and my father in law is back in town. He s much more experienced with equipment than I.
Also curious Ultradog where in Minnesota are you for
? I m originally from the cities myself and am currently in west Michigan.
 
Grew up in Aitkin. Still have property
there where I hunt, fish and play with
tractors.
Live in The Cities now.
Have for many years.
If the vent has been replaced with a plug
you can fix it pretty easily.
Drill about a 3/32" hole up from the
bottom and another at a right angle to
it. It's underneath the fuel tank and
cowel so little chance of getting water
in it.
cvphoto3671.jpg
 
So I m starting to wonder if I even have a 3400. Started to get things torn down to get the steering column removed to do the seals and the book and info I m seeing refer to 3 bolts. Also it looks more rounded in diagrams. Mine is squared off and has 4 bolts. Not too sure what to look at or where to go at this point.
mvphoto54934.jpg


mvphoto54935.png
 
That looks like the correct steering box for a 3400 with power steering. It is basically the same as the box on the ag chassis 2000 and 3000 models, but it has heavier duty arms on the sides. The parts listing shows 4 bolts holding it to the top of the transmission housing. Which manual are you using?

[u:24c4950f62]parts drawing for 3400 power steering gear[/u:24c4950f62]
 
Mine does not look like that diagram. Instead of 3 bolts to pull the column I have 4. Everything else on my tractor matches up to be a 3400 from what I can tell. Model number on the power steering I have is AE 666 50 from what I can see. I have a generator 3910 came with alternators. Lots of looking around I find that mine matches up to a 3910 parts diagram. I m wondering if someone used a 3910 gearbox to replace the original 3400 one. My issue is a leak at 20/21. Wonder if on this style I should have fluid there and have a bad gasket as I don t see multiple seals that the 3400 box had. Need to figure out and research this steering set up to see how it actually works.
mvphoto54954.png
 
I have it torn down to what it looks like on the second picture. I m looking around to find out how to take it apart further. The washer (18 )is loose and free but there appears to be a flare at the bottom of tube (7 ) above the washer to prevent me from taking assembly (8) off to get at gasket and shim. It appears there s only one seal. Number 19 which is above where my leak is at shims and gasket. (20/21) area of first picture. Is there supposed to be fluid at that gasket and shim area on this style steering gear. Originally with the 3400 there wasn t supposed to be. If there is supposed to be fluid there then I believe I may have a bad gasket?
(quoted from post at 08:07:16 05/16/20)
mvphoto54955.png
mvphoto54956.png


mvphoto54957.png
 
So I need to figure out how to get the sump removed. That all the power steering fluid lines go into Number (8). If you can see there s a washer on top of the sump then a flare on the shaft that doesn t move above the washer. Not sure how the washer comes out or the sump because of the flare.
mvphoto54958.jpg


mvphoto54959.jpg
 
[i:ac21224c81][b:ac21224c81]Mine does not look like that diagram[/b:ac21224c81][/i:ac21224c81]. Instead of 3 bolts to pull the column I have 4

What diagram are you referring to? The one I provided a link to is the official parts diagram for the 3400 and other 2000/3000 series models, and it has 4 bolts holding the steering gear to the top of the transmission. All of the pictures you have provided that are not of your tractor are for xx10 series tractors, which were made 6 to 10 years after they stopped making the 3400. One specifically says 3910 and the other says 2310, 2610, 2810, 2910, 3610, 3910, 4610SU. But even those have 4 bolts holding the gear box to the top of the transmission. You can only see three holes in the base plate because of the angle of the picture, but the fourth hole is on the far side, trust me.
 
I am not trying to take the lower steering gear housing off the transmission. I was trying to remove the assembly that the power steering lines go into. Mine takes 6 lines. 2 to the pump and 2 for each side of the tractor steering. My sump assembly has 4 bolts instead of 3 that the manual for the 3400 says it should have. The picture is the top of my sump.
mvphoto54980.jpg
 

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