Backing plate offset differences?

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Oklacarcollecto

Oklacarcollecto

Life is an experiment
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Has anyone got a rear 10" backing plate from an A-Body that used the 1 3/4" wide shoes and was sbp that they could post some measurements off of?

Also looking for the same information for the rear 10" backing plate that used the 2 1/2" wide shoes and bbp drums.

I am trying to figure out how much difference there is in the offset from where it bolts on the rear end housing. Pictures would be appreciated if possible.
 
I still have the original backing plates, factory bell drums, & 1 3/4" shoes from my Demon :)

I'm not sure what specific measurements you're looking for :scratch:

Can get pics for you in the next couple days.....
 
6pk2goDemon said:
I still have the original backing plates, factory bell drums, & 1 3/4" shoes from my Demon :)

I'm not sure what specific measurements you're looking for :scratch:

Can get pics for you in the next couple days.....
Click to expand...

From the axle flange bolts go through the backing plate to where the shoes would rest. If I have this straight in my mind you should be able to lay a straight edge across the face of where the backing plate bolts to the rear end housing and measure down to where the shoes ride.

I am looking a modern brake drum that might work on the sbp set up since our drums are extinct.
 
Oklacarcollecto said:
From the axle flange bolts go through the backing plate to where the shoes would rest. If I have this straight in my mind you should be able to lay a straight edge across the face of where the backing plate bolts to the rear end housing and measure down to where the shoes ride.

I am looking a modern brake drum that might work on the sbp set up since our drums are extinct.
Click to expand...

I was attempting to do the same thing. Rockauto.com has pics and measurements of hundreds of drums. It's like having a personal manual to reference almost any vehicle. I had posted a thread looking for drums to interchange on my car, but no one could help.
 
VonCramp said:
I was attempting to do the same thing. Rockauto.com has pics and measurements of hundreds of drums. It's like having a personal manual to reference almost any vehicle. I had posted a thread looking for drums to interchange on my car, but no one could help.
Click to expand...

I have some possible candidates found to re-drill to the sbp if a person was to change the backing plates but the unknown measurements are have stopped me dead in my tracks. Depending on the offset differences what I am looking at might not work.

Right now it is said that you can modify the front drums to use on the rear. That may work for now but my local stores have already dried up for the front drums so I am thinking they are going to be gone before long too.
 
Oklacarcollecto said:
I have some possible candidates found to re-drill to the sbp if a person was to change the backing plates but the unknown measurements are have stopped me dead in my tracks. Depending on the offset differences what I am looking at might not work.

Right now it is said that you can modify the front drums to use on the rear. That may work for now but my local stores have already dried up for the front drums so I am thinking they are going to be gone before long too.
Click to expand...

I am converting to the larger 2.5" style. I have two rear that have been re-drilled but still sport the original 4" holes. I had the flange opening enlarged on one in an attempt to use it on an after market axle. If you can use them I would let them go cheap. Neither need turning and have fresh cast paint on them. Let me know.
 
VonCramp said:
I am converting to the larger 2.5" style. I have two rear that have been re-drilled but still sport the original 4" holes. I had the flange opening enlarged on one in an attempt to use it on an after market axle. If you can use them I would let them go cheap. Neither need turning and have fresh cast paint on them. Let me know.
Click to expand...

I personally don't need any drums. I replaced all mine and stocked another spare set for future use when I saw this problem coming. I am just looking for answers that will help out all the others that are now stuck in the trap and can't find something to install on there sbp set up.
 
Maybe this will help. With the brake shoe side of the backing plate, up. The meas. from the flat area with the 5 holes where the nuts and lock washers that hold the backing plate to the rearend housing fit, to the pads that the tabs on the edge of the shoes ride against, the dim. is: 1 3/4" wide brake =17/32". 2 1/2" wide brake =
1 5/64"
 
mcode said:
Maybe this will help. With the brake shoe side of the backing plate, up. The meas. from the flat area with the 5 holes where the nuts and lock washers that hold the backing plate to the rearend housing fit, to the pads that the tabs on the edge of the shoes ride against, the dim. is: 1 3/4" wide brake =17/32". 2 1/2" wide brake =
1 5/64"
Click to expand...

Thanks a lot!

If my math is correct then the difference is 35/64 or 0.5468 of an inch[SIZE=-1][/SIZE], correct?
 
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