model 640 front support pivot mystery - help needed

kingsley73

New User
Good morning everyone, I have a problem that I can't figure out and I'm hoping someone can. I'm in the final stages of my tractor restoration and was planning on assembling the front axle and pivot pin this evening. I purchased the non heavy duty pin and bushing from Steiner, but when I drove out the old one it appears the previous owner used a piece of galvanized pipe to serve as a makeshift bushing. The new Steiner bushing shown in the photos is way too small as compared to the measurement I'm getting with the micrometer on the front axle opening.

There is a stamp on the axle of NAA3011B2 which I'm having a difficult time cross referencing. I'm not sure how to proceed. You can see by the pictures that the new bushing is significantly smaller and would leave a gap if assembled as-is. My front support calls for the threaded pin (there are threads on the rear portion of the front support). Does anyone know what I may be dealing with?

I'm at a full stop until I can figure this one out. At a minimum I'll be repainting the axle as it isn't looking nice anymore after having to drive out the old bushing with a BFH. Your help is appreciated!
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This post was edited by kingsley73 on 10/05/2021 at 01:52 am.
 
After 65 years who knows what's been done
to these old tractors.
Do you have the threaded pin and does it
fit properly - both into the bushing and
the threaded hole?
If so, you could simply have a new bushing
made with a larger OD.
If you are near the Twin Cities I could
make you one. Cost you the price of the
bronze and a 12 pack of my favorite pale
ale.
 

I wish I was closer to you, in that case! The threaded pin fits into the front support just fine, and it does thread in to the rear portion correctly. It also fits inside the bushing that I show above. What I can't understand is how the bushing is so much narrower than the hole in the axle itself.

I've been searching for another part number or bushing with a larger OD that has the same 1.75 ID that would help this make sense but thus far I've turned up nothing. I'm going to continue to try searching for an answer but you may have the right idea about having one made up.
 
(quoted from post at 04:30:53 10/05/21)
I wish I was closer to you, in that case! The threaded pin fits into the front support just fine, and it does thread in to the rear portion correctly. It also fits inside the bushing that I show above. What I can't understand is how the bushing is so much narrower than the hole in the axle itself.

I've been searching for another part number or bushing with a larger OD that has the same 1.75 ID that would help this make sense but thus far I've turned up nothing. I'm going to continue to try searching for an answer but you may have the right idea about having one made up.
It looks to me like you have a heavy duty axle that requires bushing number 312661.

Mark
 
The hole in the axle looks pretty good but they do get wobbled out after the bushing wears out. It would be good to check the opening for being round and level front to back.
 
Thank you all for the great information. This tractor frequently gives me some "Frankenstein" problems with the occasional unusual part here or there...The more I look at the axle, the more it seems like someone probably bored it out years ago when they couldn't get the old bushing in, or perhaps it got egged out and had to be honed. The chunk of galvanized pipe that was playing the part of "bushing" definitely tells me this was not a professional job!

I checked the diameter of the hole in the axle and it seems to be right-on at about 2.017 all the way around, but this seems significantly larger than any specs I can find for standard or HD equipment axles, so i suspect it's a one-off that I'll just have to deal with. The standard 1.75" pin fits into the front support and threads just fine (shown below). The good news is that I made a call this morning to a local machine shop within 15 minutes and they can make a bushing for me. So we will adapt, overcome, and move on!

Thanks again for all of the responses. I'll post a follow-up once I am able to get some form of resolution.
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This post was edited by kingsley73 on 10/05/2021 at 07:33 am.
 

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