Rear Axle: Cork rear axle grease seals

[Skip Lackie]

The original-style outer grease seals for my 3R6 rear axle used a thin cork donut inside a metal housing. It has to be centered on the axle pretty carefully, or the snout of the brake drum will tear the cork. This is difficult, as the cork doughnut is about 1/8" smaller in diameter than the brake drum snout -- the cork obviously is supposed to expand a bit to provide a tight seal. Bo Markham told me that the felt donut used as Champion crankshaft oil seals was the right size and suggested digging the cork gasket material out of the old oil seals and replacing it with the Champion felt seals instead. I will probably end up following Bo's advice, but I found that I had a pair of the original style cork seals and would like to try to use them. Unfortunately, 50 years on the shelf has dried out the cork. I soaked one of them in oil and then tried to gently increase the inside diameter of the cork gasket material a bit with one of those cone-shaped exhaust-pipe expanders. The cork doesn't seem to have been softened by the oil bath, and it started to split when I tried to open it up a bit with the cone.

I remember that old-style cork valve-cover gaskets could be softened and expanded by an overnight soak in water. Has anyone tried that approach to making one of these cork oil seals more flexible? Any other approaches that have proven do-able?

[BobPalma]

Gee, Skip; I don't think I'd try to save those. They aren't wine and surely don't improve with age. That's a lot of work to R&R the drums and clean up the mess if the salvation attempt fails. Just pack new felt doughnuts as Bo suggests and be done with it. BP

[rusty nut garage]

Skip,
Forget the cork, I've tried and the old stuff is just too dry. use the # 197591 (champion timing cover seal ). I've had the best results putting the felt seal in the housing dry then oil it, trial fit it on the hub prior to installing the seal housing on the backing plate. The felt seal is tight but by trial fitting it and letting it "sit" on the hub for a while will make sure its sized correctly so when install the hub. I've also soaked the felt seal in oil prior to putting it in the housing but it swells it so much I had real difficulty getting the hub through the housing without tearing it.
Hope this helps.

The original-style outer grease seals for my 3R6 rear axle used a thin cork donut inside a metal housing. It has to be centered on the axle pretty carefully, or the snout of the brake drum will tear the cork. This is difficult, as the cork doughnut is about 1/8" smaller in diameter than the brake drum snout -- the cork obviously is supposed to expand a bit to provide a tight seal. Bo Markham told me that the felt donut used as Champion crankshaft oil seals was the right size and suggested digging the cork gasket material out of the old oil seals and replacing it with the Champion felt seals instead. I will probably end up following Bo's advice, but I found that I had a pair of the original style cork seals and would like to try to use them. Unfortunately, 50 years on the shelf has dried out the cork. I soaked one of them in oil and then tried to gently increase the inside diameter of the cork gasket material a bit with one of those cone-shaped exhaust-pipe expanders. The cork doesn't seem to have been softened by the oil bath, and it started to split when I tried to open it up a bit with the cone.

I remember that old-style cork valve-cover gaskets could be softened and expanded by an overnight soak in water. Has anyone tried that approach to making one of these cork oil seals more flexible? Any other approaches that have proven do-able?

[Neal in NM]

When I was onboard a ship, we had 12 cylinder opposed piston Fairbanks-Morse engines which had cork seals for the crankcase access covers. When they were changed out we soaked them in plain water over night to help them expand and soften them up. Neal

[Skip Lackie]

Thanks Neal. I will probably go with the more "modern" felt seals, but in the interest of research, I soaked the NORS cork seals overnight and found that it softened them up nicely. In fact, they expanded easily and fit over the nose of the hub with no problem. Thought it was worthwhile to document this item for the record.