A body vs. B body 8 3/4 backing plates.

[cpearce]

Hello FABO,

I'm not at home right now to verify, are A body 8 3/4 backing plates the same as B body?

 

[Professor Fate]

No. A body axles have a different flange offset. (Pre '73, therefore all 8.75s)

 

[HemiSSDart]

A-Body's have 1-3/4" shoes and B-Body's have 2-1/2" shoes I believe. There is a couple of protrusions on the backing plates where the shoes rub, if you have the wrong plate then the shoes and drums do not fit! Found this out in 1994 when I sent a set out to be powder coated and they returned the wrong ones, shoes sit out to far and the drum would not go all the way on...

 

[Projectile Dart]

Small bolt axles (stock on all A-body cars) have a different offset backing plate vs all other backing plates which were all Large bolt pattern.
When you swap Large bolt pattern axles into a stock A body housing, you also need to swap to the different backing plates that have the correct offset for Large bolt pattern because the old small bolt pattern brakes will no longer work

 

[HemiSSDart]

Yes, if you are changing from small to big bolt pattern you must use the entire brake set-up. I put 11" C-Body brakes on my 69 Barracuda with cut down C-Body axles and it worked great!

 

[cpearce]

Thanks everyone, I was pretty sure they are different.

 

[rumblefish360]

Yes, if you are changing from small to big bolt pattern you must use the entire brake set-up. I put 11" C-Body brakes on my 69 Barracuda with cut down C-Body axles and it worked great!

I’ve done the same thing a few times. The entire drum assembly needs to move over. I also did an 11 inch swap on a couple of cars. Also the big disc swap as well. Gotta love them Cordoba brakes!

 

[cudamark]

Not so fast everyone....some of the mid-late '60's B-bodies had 10 X 1 3/4" rear brakes (6 cylinder cars). Those use the same backing plates as the A-body 8 3/4.