LBP 10 x 1 3/4 brake drum availability?

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dragbaron

dragbaron

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Putting a LBP 8.25 rear in a friend's '72 Duster. He got the rear end with no brake drums, so I ordered some 10 inch LBP drums. Now that I have them, they are too wide for the brake shoe setup on this rear end. My shoes measure 1 3/4, and these drums are about 2 3/4 wide.

Everywhere I look now shows the drums for 10 x 2 1/2 rear brakes. Anytime I read anything about a 10 x 1 3/4 rear brakes, it's for the SBP.

Did they make a factory LBP 10 x 1 3/4 rear brake setup?
 
Yes, they did. I have a set I got off of a 1971 Plymouth Custom Suburban station wagon with a slant six. I didn't have any trouble getting new drums. I'm sure the local NAPA, Carquest or O'Reilly's could look them up for you.
 
I believe they came on the LBP 7 1/4" axles of 1973 and up disc brake cars that were ordered with the standard axle, which was the 7 1/4"!
 
I have these, drilled for both.
$40 plus shipping for the pair if you can use them.

1522845211970.jpg
 
i have a question. if it is an 8.25 rear end with 10 inch backing plates and lbp,
why couldnt you just keep the drums and put the correct 2 1/2 inch brake shoes on it. isnt the brake hardware the same? then you wouldnt have to hunting for drums?
 
zombywoof said:
i have a question. if it is an 8.25 rear end with 10 inch backing plates and lbp,
why couldnt you just keep the drums and put the correct 2 1/2 inch brake shoes on it. isnt the brake hardware the same? then you wouldnt have to hunting for drums?
Click to expand...
It is possible, I don't remember if it requires a change of the backing plate. If you want to do it, check that. Whichever set up is used, it will best to use the matching front setup. In other words, the easiest is to the same diameter and width on the rear as the factory matched with the front brakes. Otherwise expect some adjustment in the rear cylinder size may be needed.
 
zombywoof said:
i have a question. if it is an 8.25 rear end with 10 inch backing plates and lbp,
why couldnt you just keep the drums and put the correct 2 1/2 inch brake shoes on it. isnt the brake hardware the same? then you wouldnt have to hunting for drums?
Click to expand...

8.25's were all large bolt pattern. A bodies didnt use them until 1973 and an 8.25 rear meant disc front.
 
Jimacuda said:
8.25's were all large bolt pattern. A bodies didnt use them until 1973 and an 8.25 rear meant disc front.
Click to expand...

Exactly!

All 8.25" rear axles were LBP. So, the brakes on that axle should be 10x2.5" LBP drums. There should be no need for 10x1.75" anything. And on that note, you can't use any SBP stuff with that rear axle, not the backing plates, not the drums, not the shoes. The flange offset is different, you can't mix and match parts and have everything line up.

So, the real question is, why are the 10x2.5" drums "too wide"? Because those are the standard drums for that 8.25" rear axle.
 
zombywoof said:
i have a question. if it is an 8.25 rear end with 10 inch backing
why couldnt you just keep the drums and put the correct 2 1/2 inch brake shoes on it. isnt the brake hardware the same? then you wouldnt have to hunting for drums?
Click to expand...

No, the backing plates must be a match for the brake drum width. There are different offsets depending on the shoe width. For example, 2-1/2" drums only work with the correct offset backing plates.
 
KosmicKuda said:
No, the backing plates must be a match for the brake drum width. There are different offsets depending on the shoe width. For example, 2-1/2" drums only work with the correct offset backing plates.
Click to expand...
i agree with what you are saying. in this case i just assumed the backing plates were 8.25 as well.
 
I know for sure someone didn't accidentally put the 1 3/4 shoes on a 2 1/2 backing plate, because the drums I got hit the backing plate before they touch the axle flange. This rear end has been "gone through" before by someone, so maybe they put a 7.25 rear brake setup on it.

I do have a '75 Dart Sport that I put a LBP 7.25 rear in, so I need to pull a wheel off it and see what brake setup it has on it.
 
Well, to make things easier and to actually get to use the new pair of drums I spent $70 on, I ran to my friends wrecking yard today and pulled a rear brake setup off a 4 door '71 Satellite that had an 8 1/4 rear. The parts were free, it's just the 200 mile round trip that kinda sucks! Haha
 
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