View Full Version : Rear Axle: '39 commander rear axle seal

01-04-2017, 06:29 AM
hi folks
I want to see if anyone has replaced the felt in the outer seal housing on the '39 commander rear axle (at the rear wheel). It appears the metal cup in the housing needs to be pressed out in order to replace the felt inside. It looks almost as if the felt is sandwiched inside. Problem is, I believe if I start hammering or prying the retaining "cup", it and the main housing is going to bend and get distorted. If anyone has replaced the felt, please share how it was removed/replaced. I might be able to tear the old felt out to make room to grasp the cup with a puller of some sort....but before I do, want to see if anyone can recommend the best removal method.
Pics are back side and front side of the outer seal housing.

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Also, how about the inner seal? is it similar in that it needs to be disassembled to replace the leather or felt? or can it be bought as 1 piece? (the shop manual shows it is made up of at least 3 pieces) . If it has to be disassembled, what is the best way to remove it from the diff housing without destroying it?

01-04-2017, 09:22 AM
The outer seal one can just replace the felt. You do not disassemble anything, as they are spot welded together. I believe a Champion front timing cover felt is the same dimensions for replacement. You use a sharp pick, and dig it out. The inner seals are available, and you replace the whole thing. The leather is not replaceable.

01-04-2017, 08:40 PM
got it disassembled ! had to dig out the old seal then place a large washer inside and gently press on the washer...pushing the "retainer cup" out of the housing. The "flanged part" and the front "shield" are welded but the rear "retainer cup" is not welded.

01-20-2017, 10:51 PM
on the inner axle seal...the supplier sent me a "lip seal" to replace the original cork seal. I measured the bore of the axle housing and the OD of the lip seal. The lip seal is about .014" press/interference fit to the bore. This seems excessive to me...what do you guys think?

One side of the seal is rubber and the other side is steel. It is a double lip, and appears to be a non pressure seal. There is no "inside with a inner spring" the way pressure lips seals are...just the two lips...one on each side. Does it matter side goes to the outside? the steel side or the rubber side? I dont see where it would matter except....
being formed steel, the steel side has a radius where it meets the OD. And this side is smaller in OD (this side has the 0.14" interference) than the rubber side which is a few thousandth's larger. The rubber side would also be too blunt to try to press it the hole since it has no radius.

So what do you guys think on the interference fit and ok to put the steel side inward? I do not want to destroy these seals. anyone used these on 9A commander? (1939)


01-21-2017, 06:59 AM
0.014" (14 mils) is way too much, something will distort before you get the seal pressed all the way in. I would think 1 mil to 1.5 mils max.

Added info: on some rear axles, I have seen some pretty rough looking machining where the inner seal presses in. This may make it hard to get an accurate measurement of the bore ID. Did you use a snap gauge and micrometer to measure, or a caliper?

01-22-2017, 07:37 PM
the machining on the axle bore is rough...I checked both sides with a telescoping gauge and micrometer. I found the recommended interference for that dia is .004" to .008". I made a pilot tool that will help center it and drive it in squarely. May give it a try tomorrow after talking to the supplier first.

01-23-2017, 09:19 PM
r1lark....you were right and as I suspected too....the seal distorted. $18 down the drain. the rim went in square and bottomed out flush against the shoulder but the hole is distorted little over 1/16" axially. Not good enough for me. So, I am going to custom make a bushing for the bore and purchase a lip seal with a smaller OD to fit in the bushing. This way I can get the fit to my liking.

01-26-2017, 01:06 PM
bushing and a standard seal worked out great !.....another item gets checked off the list!

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01-26-2017, 01:39 PM
Nice work.