moparspares
Well-Known Member
Is there any such thing or were all the SBP 10" brakes narrower
10 x 2 1/2 SBP Drum
- Thread starter moparspares
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bb66cuda
Well-Known Member
They were all 10x1.75"
All 10" small bolt rear drums were 10x1-3/4.
SBP front drums could be 10x2-1/2 but not until 73 iirc.
SBP front drums could be 10x2-1/2 but not until 73 iirc.
moparspares
Well-Known Member
So I take it backing plate, hardware kit is the same as the 10 x 2 1/2 except the brake shoes, drum are narrower.
Nope. Backing plate has a different offset and is not interchangeable with the BBP 10x2.5" parts. Drums and shoes are obviously different. Some of the hardware interchanges, the parking brake lever does, the springs do etc. The brake struts for the 10" SBP brakes can be used on the 10" BBP brakes, But not all the 10" BBP brake struts can be used on the SBP brakes.
moparspares
Well-Known Member
To further muck up the works...the 7.25 and 8.75 small bolt pattern backing plates arent interchangeable.
They are axle specific, different offsets.
Best bet all round is to go with aftermarket large bolt pattern axles compatible with the 10x2.5 (or larger drum) brake assembly offset.
Why Chrysler made the 72 and older A body rear brakes the way they did...well, my only thought is it had to be cheaper.
They are axle specific, different offsets.
Best bet all round is to go with aftermarket large bolt pattern axles compatible with the 10x2.5 (or larger drum) brake assembly offset.
Why Chrysler made the 72 and older A body rear brakes the way they did...well, my only thought is it had to be cheaper.
our 71 Duster has small 5 x 4" pattern with 10 x 2 1/4" front & 10 x 2 1/2" rear.
10"x2-1/2" rear isnt original to any 72 or older A body.
I'll guess you have the large upper ball joints and finned drums up front.
I'll guess you have the large upper ball joints and finned drums up front.
Jim's right on, there are no small bolt pattern 10x2.5" drums. Not originals anyway, all of the original 10" SBP drums were 10x1.75". Only way to have small bolt pattern 10x2.5" drums is to have some kind of re-drilled set up, it would have to include big bolt pattern axles that have been re-drilled for 5x4", and BBP drums that have been redrilled for SBP as well. You can't put BBP drums on SBP axles or vice-versa. The axle flange offset is different.
How about 7 1/4"vs. 8 3/4" 10" drums, are they interchangeable??
Not the A-body stuff. Small bolt pattern 7.25 brakes do not interchange with small bolt pattern 8 3/4 as far as I know.
The BBP 7.25, 8.25, and 8 3/4 brakes are interchangeable. The BBP axle flange offset was the same across the board.
I'm interested in the interchange of just the drums between SPB 7 1/4" vs. 8 3/4" for A bodies! Does anybody know if just the drums are the same, or different? I have a pair of flanged drums from a 7 1/4", and they are like new, I have been saving them as spares for my 8 3/4" rears! If they're different, does anybody know just how and where the difference is?
Sorry if this is a thread hijack, I'll moderate myself out of the convo!!
The 7.25 and 8.75 small bolt pattern drums are the same but nothing else really. Sure, some bits and pieces but not much and for sure not the backing plates.
The 73-76 small bolt 7.25 has the same drums as earlier.
The 7.25 was available in both bolt patterns 73-76.
Small was always 4 wheel drums, large was always disc fronts. (for 73-76 model years)
The 8.25 did not come with the small bolt pattern. If you have a 73-76 8.25 rear you have front discs and its all large bolt pattern.
Is everyone fully confused now?
The 73-76 small bolt 7.25 has the same drums as earlier.
The 7.25 was available in both bolt patterns 73-76.
Small was always 4 wheel drums, large was always disc fronts. (for 73-76 model years)
The 8.25 did not come with the small bolt pattern. If you have a 73-76 8.25 rear you have front discs and its all large bolt pattern.
Is everyone fully confused now?
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more I try to do the deeper it gets. 2nd guessing myself. just had it apart fixing leaky seal, new green brgs & seals from dr diff for both sides and I know that it was 10 x 2 1/2 with 4" pattern. I will double check my double check and report back. find me 2 rear drums please. I like spare parts HAPPT FATHERS DAY
Throw some pics on here, I'd like to see what you have! If you have green bearings tho, they are not OE equipment, and you undoubtably have an aftermarket setup!
No fins up front & not sure which ball joints. my guess would be the opposite of what it should be. no fins on rear drums either. have to make it a point to look again
We need pictures of what you have.
The description you're giving us is for parts that do not exist. There are no original 5x4" bolt pattern drums that are 10x2.5". You could have big bolt pattern drums that have been re-drilled, or possibly small bolt pattern drums and improper measurements. Either way, it's pretty much impossible to say what you've got without pictures or better information.
The description you're giving us is for parts that do not exist. There are no original 5x4" bolt pattern drums that are 10x2.5". You could have big bolt pattern drums that have been re-drilled, or possibly small bolt pattern drums and improper measurements. Either way, it's pretty much impossible to say what you've got without pictures or better information.
g413
Well-Known Member
Geof:
The 10" SBP drums for the 7.25 are the same for the 10" SBP 8.75. I'm sure.
I do not have 10 x 2 1/2 shoes on the rear. 10 x 1.75 like the good people here are telling me. I was sure that I was right but NOT. I would have been looking for a while. I do feel better now that what I may need is available. Egg on face - foot in mouth - we all know how that goes. Thanks to all.
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