[WANTED] SBP 8 3/4 backing plates, drums, guts

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Avispa said:
As the title says, small bolt pattern 5 on 4" rear backing plates, drums and guts for an 8 3/4 rear axle.
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I don’t think the bolt pattern matters related to the backing plate or anything else. I just put an eight and three-quarter in my 65 dart. I used a set of 10 inch backing plates that were on my B body. Everything fit fine. I went with 10“ x 2“ brake shoes and drums. Used all of the internal guts from the 10 inch brakes on my 7 1/4 rear end
 
Avispa said:
As the title says, small bolt pattern 5 on 4" rear backing plates, drums and guts for an 8 3/4 rear axle.
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Sorry, the drum bolt pattern will matter. I found 10“ x 2“ drums brand new through O’Reilly’s
 
I was following your thread about this and there seemed to be some disagreement about the backing plates, read through it, but never fully understood why it would or wouldn't work. I know the drums won't work, but what's the deal now on the BBP backing plates?
and thanks for the reply
Correction: It was the drums not the backing plates, so, looks like I'm a lot closer, not sure about paying the ebay drums at about 200 shipped.
anyway, thanks for the response.
 
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Backing plates will swap. Is this for a resto?
If not, disc brakes are an easy to do upgrade.
 
No, not a resto, but I would need a new master also, and proportioning valve.
What do You recommend as far as the disc swap?
 
Avispa said:
No, not a resto, but I would need a new master also, and proportioning valve.
What do You recommend as far as the disc swap?
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I also swapped to a dual master cylinder. I believe I bought one that fits a 72 or three duster. There’s a specific proportioning valve they sell for this conversion. When I get home I’ll try to find the number. As far as the backing plates go I don’t remember anyone staying they wouldn’t work. I put them on swapped everything over and I’ve driven the car and they work fine.
 
Is this what your looking for??? You will need the drums or I can get them as well. Thanks

A-Body plates 2 - Copy.jpg


A-Body plates - Copy.jpg
 
Small and large bolt brakes for 8 3/4” will not interchange when using the small bolt pattern axles. They have a unique offset and only run the 10x1 3/4”!brakes.
 
cosgig said:
Small and large bolt brakes for 8 3/4” will not interchange when using the small bolt pattern axles. They have a unique offset and only run the 10x1 3/4”!brakes.
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Your talking about the backing plates?
 
Avispa said:
Your talking about the backing plates?
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And the drums as well. Everything is based off of the offset of the axle flange as it sits in relation to the housing. It extends out a certain amount, the drum mounts to the face of the flange, and the brakes are back set from that. So, since they are set to use an 1 3/4” shoe, and the shoes are mounted to the backing plates, a 2” shoe would be too wide, and a 2” drum would rub the backing plate. Redrilling the drums and axles is the old school way to use the existing brake setup for a large bolt pattern. Nowadays, they make up that difference in an aftermarket axle already drilled for large bolt and offset to use large bolt brakes of any configuration. Of course, Dr. Diff still sells axles in the original 1 3/4” offset that would only require redrilling your drums if he makes them with the large bolt pattern and you still want to use your existing brakes.

confused yet?
 
cosgig said:
And the drums as well. Everything is based off of the offset of the axle flange as it sits in relation to the housing. It extends out a certain amount, the drum mounts to the face of the flange, and the brakes are back set from that. So, since they are set to use an 1 3/4” shoe, and the shoes are mounted to the backing plates, a 2” shoe would be too wide, and a 2” drum would rub the backing plate. Redrilling the drums and axles is the old school way to use the existing brake setup for a large bolt pattern. Nowadays, they make up that difference in an aftermarket axle already drilled for large bolt and offset to use large bolt brakes of any configuration. Of course, Dr. Diff still sells axles in the original 1 3/4” offset that would only require redrilling your drums if he makes them with the large bolt pattern and you still want to use your existing brakes.

confused yet?
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Well, kinda. I stopped at O'reilly's, they have 10" SBP drums, but she's telling me they use either 2 1/4 or 2 1'2 shoe's, can't remember which, 56 bucks each, one day wait.
 
Avispa said:
Well, kinda. I stopped at O'reilly's, they have 10" SBP drums, but she's telling me they use either 2 1/4 or 2 1'2 shoe's, can't remember which, 56 bucks each, one day wait.
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I would be shocked if they had anything small bolt at all, and if they use anything other than 1 3/4” shoes, they are not small bolt and not correct for A body 8 3/4” rears. I would venture a guess that they are large bolt for 73 and later 7 1/4” large bolt axles.
 
Avispa said:
Well, kinda. I stopped at O'reilly's, they have 10" SBP drums, but she's telling me they use either 2 1/4 or 2 1'2 shoe's, can't remember which, 56 bucks each, one day wait.
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those are the exact drums in just bought last week for the exact same application. Changed my 65 dart to 8 3/4 SBP. They work perfect!!!! Should be 5 bolt by 101.6mm which translates to 4 inches. They do use 2.25 brake shoes as well. I used all the same rear brake hardware from my 10” 7 1/4 set up and everything switched over great!
 
Yep, that's them, the screen said 5 bolt and 101 mm spacing, and 2 and something width, I couldn't believe they were listed, had to drag out the phone to convert the 101 mm to inches, which turns out to be 1"= 25.6 mm. 56 bucks and in stock at the warehouse.
 
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