D14 steering control valve leak

Ok - finished a total restore on a 59' D14. All is well, runs great, tranny shifts great, lots of fun. Of course life is usually good at giving us a problem. This was leaking oil from every single one of the seals, gaskets and o-rings. When done and running , looks like we are all good except what i think is an oil leak on the bottom of teh steering control valve. See the three ball bearings in the picture above. I rebuilt this unit about a year ago as part of the total overhaul. I don't remember these balls coming out, and candidly, the parts page barely shows them (seen above the #20 in the pic). So the question is what to do.
i don't remember any springs, etc above them. i'll assume from the picture that they are simply setting in a recess at the bottom of the pump. Anyone have
experience with these ? Odd there are no part numbers for them either. Thanks for all help.


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They are there to plug a drill hole to make an internal passage. They are not intended to be removed. If they leak you may have to take the valve apart and weld them to stop the leak. They seldom give trouble, are you sure the leak is not from something else?
No, I’m not. I’ve gone through exploded ire of the steering motor and besides that there is little above it that might be causing this. There is one seal at the rear of the steering motor where the steering shaft goes thru. I did replace that seal on the rebuild but I still remember thinking wow, this is a super wimpy seal . I clean off the bottom of the steering motor ,start it , run for anew monies , and bingo more oil on the bottom of this . I guess that one guess-test would be to silicone over those theee balls and see if the leak lessened . I personally think I’m leaking from somewhere above
So I would clean it with brake clean or ether and get it completely dry, use a blow gun with air and make sure completely dry, then start engine and get under and watch up for first sign of leak. The elbow is tapered pipe thread, may be cracked or just leaking in threads. The three line fittings are inverted flare, they some times like to seep, can be easily cross threaded, the two directional lines have separate seats in the casting that could be bad or the flare on the line could be bad. Keep looking. It is coming from somewhere. Great paint job. Would like to see complete tractor.
Well, drug this home non-running . Didn't know boo about A.C. tractors, but some study lead to the tear down. Originally, i was just going to "see if i could get it to run" . You know how that goes - once stripped, it was then well, torn down this far, maybe i should get out my paint equipment. Built a tent around the tractor , spent a ton of time stripping, sanding, bodywork on the fenders, etc.. Final product is near flawless, and grabs the attention of anyone that comes in the shop. Had a good time with this, and still am amazed at the technology of the 1950's . Last detail is to find this leak . thinking the exact same thing that you have prescribed. Gonna have the Mrs. sit on the tractor and rock the steering wheel back and forth a little to see if the control motor starts to leak or will the adventure lead somewhere else......


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I'll bet your leak is running down from another area. I've never had an issue with those drive in ball plugs.
Think you are right. Going to exit work early and use my scope to look on top and fingers to look below.
I , too, think i have a leak up the ladder. i'm leaning on the seal that the steering column goes through. It is
remarkebly frail and i notice the actual column shimmys a little while turning. i'm looking there first. I really hope it isn't
from that spot. New seal, and it leaks is not a great combo.
Well for sure there is oil bypassing the new seal i put in the rear of the steering motor. (#1 in the schematic) Really not sure why, but there is oil by-passing the steering shaft. The question is if i can get it out without pulling half the front end apart again. Doc - your the word of experience. have you replaced that seal with the powersteering unit in place.


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I have not, but could if I had to. Be nice if side frame was removed. Probably have to polish off the paint on the shaft to protect the new seal when sliding it on.
Removed the side frame, and the seal won't quite slide on the steering shaft (hits the engine block). So, pulled the front support again, and
changed the seal. while apart, i did fabricate another steering shaft support (in pic) guessing that a small chance existed that the "wobble" in the shaft was pushing the control motor seal to the side enough to cause it to leak. Also noticed that the very bottom pressure line had been replaced with a piece of copper. That would probably mean a 45 Deg. flare, and i think these were all 37's , So, replaced that line, and no leaks there. At this point, the only thing i can think of is that i made some type of error when rebuilding the steering control motor. Rebuilding it really just means replacing the o-rings inside, and putting everything back together. That rear seal is pretty whimpy, so i can't image it is designed to hold back pressure, more like a gravity oil stop. Wondering if that inner cavity is somehow being pressureized, and it is forcing oil back through this seal. Hints to this are that the seal leaks once the engine is off, not sure if it is also leaking when driving. i also have a little bit of a delay when quickly turning the wheel from left to right. barely noticeable, but it is there. I guess at this point, live with it until i have time to pull the front support again and take apart that control motor and try again.


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I suppose if the adjusting nut under that seal cap was too loose, there could be excessive oil being allowed into that area. I've never had a nut too loose, so I'm guessing at what the ramifications might be. 1 turn loose could make a difference in what's going on, but that's speculation on my part.
Manual says that nut should be 3-5 ft lbs. I am wondering the same dang thing. Only way to know is take it apart again . I am not totally fluid on how this motor works, but studying the schematics. Now in hopes some insight will help supply an answer . As always, thanks doc for
Help .
Ok - finally much progress. Some guy had a steering control valve off of a 65' d15 for sale on ebay. i bought it before tearing the front end down again. Quick dissasembly of the ebay part to replace the seals, and painted the body. Tore the front end down again, and pulled the old steering control valve out. It was leaking badly from the old seal, and had lot of play in the steering shaft. i'll examine it later, for now just put the new one in, and reassembled. I also doubled the seal on the rear of the steering control valve. Interesting, the 65' new part i had's seal was twice as deep as the new AGCO seal. I happened to have a spare, so two went back in.

Unhappiness followed a day later. Saw a small leak which traced to the steering ram cylinder on the opposite side of the tractor. JKKKUUUU!!!!!!
On inspection , there were actually two leaks. Somone had replaced the steel high pressure line that goes from the pump to the control valve on the other side with a copper line. That fitting was leaking. Surpirse, that steel line is still available from AGCO. Ordered it, and i'll add a piece of info. on the rear seal for the steering ram. Couple of people asked about this becuase their's was leaking too. Tips to fix this:
1/pull off the side frame support. Put a jack under the front support first, and just gently put pressure on it. That will keep it from drooping once the side rail is off. The hydro line nut gets unscrewed , no biggie there. That retainer ring is a different story. Important tip - drill a 3/32 hole about 3/4 way thru the retainer close to the end. Look closely and you will see it by my index finger. Then get your woodshop small nail punch and insert in the hold and pry that buggar off. Now simply pull the valve off. I was surprised at two things : the junk in the ram cylinder body. Clean this well. I had already done this, but more got deposited there. 2/upon inspection, the AGCO seal that goes inside of this valve does not begin to touch the actualy cylinder. Look at pic 3. what you see is the other side of the valve,. Remember, i ordered the correct AGCO seal for this when the original rebuild took place (maybe 4 months ago). I also ordered another for this repair thinking the original must have been a part defect from agco.
Nope - same seal, same size. (part # on right image below). Instead of this seal, i tried a metric seal out of my oring set that was actually 1mm bigger in diameter. Once it was in the retainer, it protrouded just a little, and sliding it back on the ram gave it just a little "snug" feeling.
So, i had to stop there for this morning. I'll reinstall the new oil line and finsih this up. If no leaks, i'll not post again. Hope this helps someone else.


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It is great information. Those of us that have that ram leaking appreciate the been there done that experience. I have been adding fluid every so often to replace the dripped out which is ever increasing. I just HATE removing the loader from the working tractor and diving in until I have to AND kind of have a clue on what attack method to use. Your info is the ticket!

That seal size for the ram is perplexing? Following along with your detailed info is VERY informative and helpful. Keep us posted.

Glad to help - one other "remember" before you start this. The seal i'm pointing out is inside of the valve i'm holding.
There is also another, bigger one on the outside of the valve. Don't forget to have that oring too so it can be replaced.
Good luck, let me know if you need anything else.
Well, some good news. Finished re-installing the high pressure power steering line . Rear cap back in on the steering ram.
Held my breath and started it up. No leaks. Drove it around the field for about 30 minutes. No leaks. So, with that, this d14
is finished and in really good condition. woo-woo! Now, ,,, back to facebook marketplace to see if a d17 might be waiting out in the field somewhere,,,,,,
Good work! You saved another one. I enjoyed following along with your progress. Your attention to detail helped me with my project D-14 too!
Thanks. It was worth all the work. Pretty familiar with this model now. Glad to help if i can. Also want to thank
Doc Allison - gave me a couple of tips along the way that really helped! rasman57 - one question for you.
Do you pull a plow with any of your 14's? I got a smoking deal on a 3-bottom snap coupler plow, and it's probably my next remodel.
I am afraid that the 14' won't have enough ponies to pull this beast. So, wondered if you had experience with this.
Thanks. It was worth all the work. Pretty familiar with this model now. Glad to help if i can. Also want to thank
Doc Allison - gave me a couple of tips along the way that really helped! rasman57 - one question for you.
Do you pull a plow with any of your 14's? I got a smoking deal on a 3-bottom snap coupler plow, and it's probably my next remodel.
I am afraid that the 14' won't have enough ponies to pull this beast. So, wondered if you had experience with this.
I have only used a 2 bottom in pretty cooperative ground. No problem. But the ground will tell. Interestingly enough, the plow was actually a 3 bottom frame that had been modified by simply removing the back plow to accomodate the use for my native grasses and food plant mission.

Plenty of D-14 fellas here will provide insight too I would think.

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