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I have an interesting problem that I figured would be of some interest.

My dad bought a 1972 (I believe) IH 3500A backhoe at an auction back in the later 80s or early 90s. My uncle and dad have since used this machine countless hours for many different projects. Lately it gets used to repair tile lines in farm fields, so still finds good use every year. The major drawback we recently discovered is the top main bushing/seal are shot on the hoe pivot and we may have a bad bottom bushing/seal as well.

We have the parts, service, and operator's manuals for the machine but have run out of places to go for parts. The local RMS (Road Machinery Supply, Komatsu dealer) basically recommended it all be custom-fabbed as no one there knew anything about looking up parts for the old IH construction equipment. Our problem is we don't have parts specs or original parts to go off of and are hesitant to remove the hoe if we can't put it back together.

I will update with pictures soon, attached now are 2 pictures showing the area I am referencing on a similar machine I found in old auction listings.

Right now I was wondering if anyone knows where to get either parts or part specifications so we can fix this issue?

Below is a link to a very similar issue another forum ran into:


I have found a few forum topics related to different issues with the 3500 Series A, but those all appeared to be in Europe. I’m located in the Midwest USA.




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Will need to see more specifically where the leak is coming from. But I have done extensive research on this swing system, since your 3500A should be the same as my newer 270A backhoe.

You are correct, nobody knows these hoes anymore, and there is no "one stop shop" for parts. However many individual components such as seals, O rings, and bearings can still be got through various vendors if you know what you are looking for. I have compiled a list of part numbers and sources, but in order to answer your question I will need to know more about what parts you specifically need. Unfortunately there are a few that have turned out to be impossible to get. As soon as I can find a NOS or good used example I plan to try and get them recreated.

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Sorry for being so long to reply, going to the machine again today to assess some more. That thread about the nut removal is encouraging.

I did find out I do not have a service manual, just parts and operators. This machine is also a 1975 3500 Series A according to the manuals. The parts page looks almost identical to what @Binderdan posted.

Attached is the parts page I have, along with the additional pictures I promised. The nut I have has more holes for removal, so I don’t know if that makes a difference. Our appears to have either the nut or the whole support piece wore. As some of the pictures show though the shaft splines underneath appear to be farther out that they should be, leading me to think it might be possible to just tighten the shaft and the issue would resolve. The bottom of the shaft where those splines are is also the leaking area, and one picture should show what it looks like above the bottom support.

On a side note, in the other thread there was discussion of the bearing and it being ungreasable, our pivot has a grease zerk below the nut on the side of the pivot assembly that is about where I would expect the bearing to sit, along with the bushing. That is what I am assuming referencing the parts breakdown and the information on the but from the other thread.

at this point we might try tightening that nut but we also don’t have the tools and may not be able to make them, we’ll see how far we get there.

What I have attached is all the pictures for now, if anyone thinks we need more let me know and I will try to get them.



















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How fast is it leaking? Just a dribble or pretty bad?

I'd power wash the whole swing area really good and let it dry, then operate the machine to try to pinpoint the source of the leak. From what I see in the pictures it looks like the lower swing seals could be leaking but the areas around it like the hose bundle are wet too so a leak from above can't be ruled out. Wouldn't want to take on disassembling this whole thing for nothing. Its a big job.

I was able to find most of the O rings and seals on the swing shaft in your parts diagram(#8, #3, #7, #13, #14). Although 2 of them(#8, #13), are questionable.

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  • 2 weeks later...

The leak is not fast, and it may very well be coming from the hoses as they are wearing through. Right now it’s looking like we might not tackle anything until spring unless I can figure out a way to try and turn that nut and see what else I’m dealing with.

Is there any copy of a service manual available that I could look into? Everything appears to be similar to the other pictures and posts but not exactly the same. 

The nut has definitely wore into the main support on top and I worry the bearing and shaft may be wore as well. I do wonder though where the bushing sits to prevent that shaft from wearing but it seems impossible to tell with the way it sits right now.

Once I get the nut moved I will report back, hopefully in the meantime I can find some service literature to see what I should be looking for underneath.

Thanks for the help so far.

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You can buy reprint chassis service manuals from JenSales(digital PDF, or paper copy), or a used one on ebay.


Although the information on the swing is pretty vague in the manual. That nut on my 270A is torqued to 1050 ft lbs per the manual, probably the same on 3500A. The link that Hardtail shared is to my thread where I removed mine. Shows the tool I made and how I used it.

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