Inner axle seal replacement

[rob love]

Just thought I would do a quick thread on a repair I am doing here at the RCA museum. One of the gun tractors sprouted a leak of gear oil at the knuckle, indicating the inner axle seal has, after only 70 years, had enough.

Luckily this one is a (uuugh) Chevrolet, so changing the axle seal is relatively easy. You just have to remove the complete knuckle at the flange on the axle. You will then see the poor old seal. I have not found a direct replacement, although I used to find a pretty close one back in the early 90s, but even then it was going obsolete.

The inner axle seals off the rockwell axles, as used on the M35 family of trucks (MLVW in Canada) have the right inside diamter, and come in a steel retainer that is unfortunately too large an outside diameter. The NSN for the M35 seal with retainer is 5330-00-075-1764 and they are readily available on the surplus market or on ebay.

I have included a photo of removing the knuckle using an electric pallet stacker. This worked out welll. You really don't want to be dragging the seal with the axle shaft. As well, the whole assembly is quite heavy. You may want to remove it in pieces, however as this is a rush job and I have the equipment it is being done this way.

Here is a shot of the tool you will need along with a slide hammer to remove the old seal. They are in there very tight.

Here is a shot of the old seal next to the MLVW seal and retainer. To make the MLVW seal work, you need to duct tape the seal and turn the retainer on a lathe to approx 3.620.

Here is a shot of the retainer and seal in place on the axle housing. Sealant has been applied to the outer edge to prevent oil from leaking past, although with the tightness it is not likely.

The axle shaft showed some wear at the original seal area The new seal moves the wear surface inwards so it will no longer be using the original wear surface.



Anyway, got to run. Time to install the knuckle and have it all together and brakes bled by this afternoon.