Construction and other equipment - FA 10 Final Splines and Seals

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FA 10 Final Splines and Seals

Printed From: Unofficial Allis
Category: Allis Chalmers
Forum Name: Construction and other equipment
Forum Description: everything else with orange (or yellow) paint
URL: https://www.allischalmers.com/forum/forum_posts.asp?TID=173349
Printed Date: 19 Aug 2025 at 1:47pm
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Topic: FA 10 Final Splines and Seals

Posted By: Ian Beale
Subject: FA 10 Final Splines and Seals
Date Posted: 05 Aug 2020 at 5:40pm

uploads/5937/FA_10_Sprocket_Carrier.jpg" rel="nofollow - uploads/5937/FA_10_Sprocket_Carrier.jpg

We've been part way in here when we were rebuilding the track gear.

When the sprocket carrier is pressed on the inner spline end is supposed to be Dimension "h" - 2 - 4 mm inside the outer spline.

This one must have been run with the sprocket loose, as the inner protrudes maybe 1 - 2 mm (IIRC from about 10 years ago). The nut has been built up and lathed out to provide clearance when it is tightened. We didn't have a press to check but it passed the "rings like a bell" hammer test and doesn't move now.

The sprocket seals are duocones.

So that (seems to me) means that the inner seal is compressed maybe 4 mm more than design and the outer less - unless there has been some "farmerizing" that I'm not aware of.

It survived like that for quite a while. We've done around 3000 hours since the tracks rebuild. AFIK the two previous local owners weren't in there (by the state of the track gear when we got it) so maybe the third owner back. Someone back in its pedigree had a lathe, as there was 20 mm machined off one bearing surface on the blade cylinder pivot shafts to fit bushes that came from "somewhere".

So are new seals likely to last? I don't want to have to do this twice.

Or should I look at finding a second hand set for the sprocket carrier assembly? There don't seem to be a lot of FA 10's in wrecking yards down here.

I don't know if the finals case has been opened before we got it. It is an early serial where they used gaskets there, later ones have no gaskets and use Cat Red gasket sealer. These earlier ones got a spacer instead of the gasket between axle case and the inner finals case. One clue might be that the part numbers for the gaskets are crossed out in ball point in the parts book.

Replies:

Posted By: steve(ill)
Date Posted: 05 Aug 2020 at 6:41pm

I would have thought that 4 mm ( .170 inch) was too much compression for the inner seal, but apparently the rubber will give that much .... unless they have done some trimming... I guess my concern would be the outer seal having enough compression to seal. If they didnt put a space or washer under the seal, then them must have ASSUMED the rubber did have some compression to seal. I would not have guessed that, but if you have 3000 hours on the seal and it was working, that tells you something ..... getting that sprocket pushed on TIGHT is the real deal.. Maybe you can use a couple all thread rods with a backer plate and use a small hydraulic jack ? I have also seen guys heat up the spline center to expand the metal, then push it on.. Its hard to use the nut to do all the pressing, but if thats all you have, make sure it is slugged down GOOD.. Antisize on the threads may allow you to get more "torque".

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Like them all, but love the "B"s.

Posted By: steve(ill)
Date Posted: 05 Aug 2020 at 6:51pm

The problem we use to have with the bigger tractors was not seal compression, but keeping the sprocket tight.. After it starts to work on the shaft, it gets some wear and the pattern is not quite right.. You push it on further, but the spline "FIT" seems to be the problem. One thing we were doing was spreading BELZONA ( liquid metal) on the splines prior to pressing them on... That was suppose to fill in any imperfections and make a better seal.. It did seem to help long term.

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Like them all, but love the "B"s.

Posted By: Ian Beale
Date Posted: 05 Aug 2020 at 7:19pm

Steve

Thanks. The press on is 40 - 50 tons. We can handle that as one son is a Cat trained big machinery fixer with his own business, service truck and plane - "Have spanners, will fly".

I've got a spare nut from which to make the adapter.

I've also got that question in with one of our long-term Fiat suppliers who have worked on them for a long time. No answer back as yet.

Posted By: Ian Beale
Date Posted: 07 Aug 2020 at 3:14am

Better news. It is most likely the sprocket side that is worn. And they're available new.

Also assured that the FA 10 parts supply situation is good.

More when we know more.