# What are the size of the factory backing plates?



## 70conv (Jun 25, 2012)

Guys,

I'm about to order a new 12 bolt rear to replace the 10 bolt in my 70 GTO. I want to stay with the factory brake set up to minimize the installation hassle, with the e-brake and whatever. I'm looking for a new set of backing plates and the ones I have found seem to be for 9 1/2 brakes. Is that the factory brake set up? Planning on just transferring over all my brake components. Thanks for any help.

Mike


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## PontiacJim (Dec 29, 2012)

70conv said:


> Guys,
> 
> I'm about to order a new 12 bolt rear to replace the 10 bolt in my 70 GTO. I want to stay with the factory brake set up to minimize the installation hassle, with the e-brake and whatever. I'm looking for a new set of backing plates and the ones I have found seem to be for 9 1/2 brakes. Is that the factory brake set up? Planning on just transferring over all my brake components. Thanks for any help.
> 
> Mike



My opinion here as I am not an expert on this, but the 12-bolt and 10 bolt will be different. The Pontiac 10-bolt uses a plate with 4-bolts to hold the axle in. The Chevy 12-bolt uses C-clips to hold the axles in. I am not sure if you can simply swap backing plates as the axle tube ends may be different as well as axle tube size - but just assuming at this point.


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