VCCA Home Forums TECHNICAL - 1945 AND EARLIER 1929-1932 31 Axle Bearing - Sealed

Anyone have the correct part number for a sealed rear axle bearing for my 31? Looking to go new style...completely sealed.

If you have the standard number any GOOD brg supplier will be able to get you a sealed bearing. Also when putting in a sealed bearing you should add a vent to the axle housing otherwise it will build up pressure and leak . Do a search on the site as there are various solutions for the vent.

The original P/No. for the rear axle shaft bearing(non sealed),is a new Departure N3307.It fits the following models:K,V,AA,AB,AC,AD,AE,and is a maximum capacity bearing.The modern number for a standard ball bearing,depend on the brand,is a 6307(LLU in an NTN with 2 rubber seals),the maximum capacity in an NTN bearing with one steel dust shield is a BL 307Z.

I don't know if it's the same bearing dimension but I installed Timken #208KDD rear wheel bearings on my '32 Chevy.

No Charlie it is not the same.

The axle bearing for a 1932 BA Confederate is a New Departure N3208 maximum capacity bearing,which today is the same a 6208 2RS/LLU ,with 2 rubber seals.For a maximum capacity bearing,in an NTN brand,the number is a BL208Z with one grease shield.Rubber seals aren't available on maximum capacity bearings,due to the filling slots in both the inner & outer races for the extra ball bearings.

Thanks for the vent info.....I did find a source for my bearing and decided to do both. They were not the same but bearing headquarters was great to work with.

Thanks.....I did as you suggested.

When drilling and tapping the top of either axle tube, most stay about 6” inside the perch. To prevent metal chips from falling inside the tube, I do a few things. I have a spare rear cover plug drilled and tapped for a air line fitting. I put about 20 psi flowing into the rear while I drill. Drill slowly as the drill gets close to breaking through and put some grease on the drill tip to help catch filings also. Once drilled, leave the air flowing, put some grease on the pipe tap, and cut the threads slowly too. This should prevent any filings from going inside the tube.

I have also heard of drilling a hole lengthwise in one of the top bolts holding on the differential cover and then inserting a cotter pin but I have not got to that point yet.

Dave

That's what I did, it's an easy fix. I think I drilled 1/8" or 5/64" and put a cotter pin in.

can you post a pic of what you did ?? like to see it

I got this idea from a previous posting. It's easy to do and undo. I haven't driven it enough to know if it would leak, but I don't think enough to be a problem.

Thanks for the picture. Why do you insert the cotter pin? Is it to keep moisture out of the differential? It would seem you are just filling the hole that was drilled.

Pressurized air can move in either direction around the loose-fitting cotter pin. Water on the outside and oil on the inside will have less ability to pass.
An open hole would allow liquids and dirt to pass more easily...

I'm wondering if a one-side sealed type bearing could be added to later axles - like my 1938? Be nice to reduce chances of a leak.

Here's a photo of my drilled out top cover bolt showing cotter pin in place. The pin fits loose enough to permit adequate venting of the axle. After several hundred miles, no issues. Very very slight weeping of gear oil.

from the hole.

I think the cotter pin is there because it will rattle and move. Drill a plain hole and some insect will plug it with mud so fast you wont believe it.

Hardaground: I am planning on doing exactly what you did. Which hole do you have it in and how bad does it weep?

I agree with Bloo, The cotter pin is essential to keep the hole open while better controlling the actual size of the vent opening.

That is a trick that even the great Henry Ford knew. If you look at the bottom of the clutch cover on a Model A you will see a large cotter pin sticking down. The hole is very necessary to let out all the oil that leaks past the rear main. The pin moves around and keeps the hole open. Think about all the dust that from the dirt roads back then and how quickly that would plug the hole. It would not take too many miles before the dry clutch became a wet clutch (even though it was not designed to operate as a wet clutch).

Putting a single seal-bearing in vehicles like Tim's is an interesting idea. It would give a second seal to as extra insurance against leaks. On the other hand would the seal in the housing fail because it was running dry?

A single-seal bearing would be a quick fix for an axle that had a groove worn in it from the original seal.

It's in the top right bolt hole, approx 1:00 o'clock position. I just took this photo. You can see what it looks like after a few hundred miles with a slight wet trail running down. When under way the oil splashes around and some finds its way out around the pin but never leaves a spot on the garage floor. I check the level on occasion just to be safe and it's fine. A tapped hole for a breather vent cap in the axle would be the best but I have an aversion to drilling into a perfectly good axle housing.

Thanks!

I install the actual vent used by GM on later axles and originally on the 37’ driveshaft tube.

I'm not sure if 31 and 32 are similar enough, but here's a link to the thread I made when I changed my bearings.

31 bearing replacement thread


And here's a link to the tread where I drilled and installed my vent

Vent Installation

1932 Engineering says 1932 bearing is of a larger diameter.