'40 - '48 rear hubs

[meric42]

Can someone enlighten me? Are the rear hubs different depending whether fitted with drums on the inside versus drums on the outside of the hub?

Thanks in advance

[Andy]

Yes. They moved the flange where the drum rests so the track remains the same with either style drums.

[Russ/40]

I just pulled the hubs off two drums. One was outside the drum, and one was inside the drum. Both hubs were the same. The only difference was with the drums. One drum is deeper to accomodate the hub. The hubs had slightly different hole sizes. When cutting the swag away to release the drums, the hub that is outside mounted is the one that gets cut when removing the swag. The holes were larger on the outside mounted hub.

Revision, ignore this post as it is incorrect.

[meric42]

Originally Posted by Russ/40

I just pulled the hubs off two drums. One was outside the drum, and one was inside the drum. Both hubs were the same. The only difference was with the drums. One drum is deeper to accomodate the hub. The hubs had slightly different hole sizes. When cutting the swag away to release the drums, the hub that is outside mounted is the one that gets cut when removing the swag. The holes were larger on the outside mounted hub.

Thanks Russ, I thought that was the case, but don't have any at hand to check right now. Cheers, Meric.

[Andy]

Originally Posted by Russ/40

I just pulled the hubs off two drums. One was outside the drum, and one was inside the drum. Both hubs were the same. The only difference was with the drums. One drum is deeper to accomodate the hub. The hubs had slightly different hole sizes. When cutting the swag away to release the drums, the hub that is outside mounted is the one that gets cut when removing the swag. The holes were larger on the outside mounted hub.

The 40-41 drums flanges are taperd on the back with raised bosses for the studs. The 42-48 flanges are flat on both sides. The 40-41 hubs have a pilot ring only on the outside and the 42-48 has the pilot ring only on the inside. The flanges are shifted to keep the track the same.

[V8COOPMAN]

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Originally Posted by Russ/40

I just pulled the hubs off two drums. One was outside the drum, and one was inside the drum. Both hubs were the same. The only difference was with the drums. One drum is deeper to accomodate the hub. The hubs had slightly different hole sizes. When cutting the swag away to release the drums, the hub that is outside mounted is the one that gets cut when removing the swag. The holes were larger on the outside mounted hub.

RUSS......Does that mean that BOTH hubs (inside & outside) have the same "01A" number embedded into them? DD

[V8COOPMAN]

Originally Posted by Andy

The 40-41 drums flanges are taperd on the back with raised bosses for the studs. The 42-48 flanges are flat on both sides. The 40-41 hubs have a pilot ring only on the outside and the 42-48 has the pilot ring only on the inside. The flanges are shifted to keep the track the same.

What ANDY is describing is much more in line with what I've run across over the years. DD

[1oldtimer]

I thought that the rear hubs where also thinner on one of them.....I think it was the inside ones????

[Russ/40]

I was wrong. Further inspection shows a few differances i just did not notice. I apologize for missleading you. Hubs removed from the drums, I can make these observations.
1. From the outer end visable as they are mounted on the car, both hubs are virtually identicle.
2. The flange on both are 1/4" thick
3. When the hub is mounted outside the drum the locating diameter of the hub is 4".
4. When the hub is mounted inside the drum the hub locating diameter is 4.9"
5. The drums each have the 4" or the 4.9" hole for the hub.
6. When the two hubs sit on the bearing side the flange is .100" higher on the hub that mounts external to the drum.
7. I believe the hub that mounts externally could be used in both applications. If the locating diameter of the one that mounts internally was turned down, I believe it too could be used in both situations.

Unless I mount both hubs, i cannot be sure if any interference would be caused by the .100" difference with the backing plates. It might be enough to cause a rub from drum to back,plates.

I hope I am being articulate enough to convay the point. I am working on a project to change my stock '40 drum brakes to 11 inch Bendix brakes. I plan to use both of my hubs internal to the drums. I will be drilling the hubs for the later 5 by 4.5" bolt pattern. Again, my apology,and comments are welcome.

[Mart]

Gut feeling tells me that if you are considering some sort of conversion, starting with an identical pair of hubs would get you off to the best start.

Mart.

[V8COOPMAN]

Originally Posted by Mart

Gut feeling tells me that if you are considering some sort of conversion, starting with an identical pair of hubs would get you off to the best start.

Mart.

X 2 on that! On the other hand, it will be interesting to see what your research and experimenting comes-up with. DD

[Russ/40]

No matter what hubs i use, there is machine work to do. These two I have will be identical when I'm finished with the mods. The smaller bolt pattern dictates what needs trimming. Fortunately, there is plenty of meat to work with.