Duster disc brake conversion
#2722517
12/08/19 12:31 PM
12/08/19 12:31 PM
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Joined: Sep 2011
Posts: 1,487 STL
cdstl
OP
pro stock
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OP
pro stock
Joined: Sep 2011
Posts: 1,487
STL
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My son and I will probably convert his 70 Duster to discs this winter. He has the factory 8.75 rear end and this is going to involve purchasing some big bolt pattern axles from Dr. Diff.
I haven't looked into everything completely, but I understand that the A body 10" rear drums have a 1.75" brake shoe and the big bolt pattern axles will need 2.5" shoes. This will require different backing plates.
The question is this. Which brake backing plates can I use for the bigger shoes? B,C or E body 10" drums and backing plates? Any of those or all of those.
Thanks
1972 Cuda 340 4 speed, 2001 Ram CTD 4x4 6 speed, 1970 Duster 408 4 speed, 1996 Ram 5.9 2x4 auto, 1965 Coronet 500
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Re: Duster disc brake conversion
[Re: cdstl]
#2722525
12/08/19 12:53 PM
12/08/19 12:53 PM
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Joined: May 2019
Posts: 6,326 nowhere
Sniper
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master
Joined: May 2019
Posts: 6,326
nowhere
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My son and I will probably convert his 70 Duster to discs this winter. He has the factory 8.75 rear end and this is going to involve purchasing some big bolt pattern axles from Dr. Diff.
I haven't looked into everything completely, but I understand that the A body 10" rear drums have a 1.75" brake shoe and the big bolt pattern axles will need 2.5" shoes. This will require different backing plates.
The question is this. Which brake backing plates can I use for the bigger shoes? B,C or E body 10" drums and backing plates? Any of those or all of those.
Thanks Any one other than the A body SBP ones will work. You can also us FMJ and R bodies as donors. I had a set of M body cop 11" drums on my 8 3/4 for awhile. I believe Doc Diff sells a drum brake kit all ready to go and all new. Might save on shipping if you go that route when you get the axles.
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Re: Duster disc brake conversion
[Re: Sniper]
#2722536
12/08/19 01:07 PM
12/08/19 01:07 PM
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Joined: Sep 2011
Posts: 1,487 STL
cdstl
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OP
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Thanks for the reply. He does have an entire assembly ready to go for $475. It's going to boil down to what it will cost to piece everything together vs using his out of the box parts.
Thanks
1972 Cuda 340 4 speed, 2001 Ram CTD 4x4 6 speed, 1970 Duster 408 4 speed, 1996 Ram 5.9 2x4 auto, 1965 Coronet 500
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Re: Duster disc brake conversion
[Re: hemienvy]
#2722757
12/09/19 02:49 PM
12/09/19 02:49 PM
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Joined: May 2019
Posts: 6,326 nowhere
Sniper
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nowhere
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If a person bolts on the bigger brakes onto the existing A-body housing, and buys new axles instead of redrilling the old axles, aren't the new axles longer by about 3/4-in ? If you don't narrow the housing, the bigger brakes are wider so you need longer axle shafts, or so I thought. Yes, you are correct. The Doc Diff BBP axles are setup for the swap he's doing. Some other people like to muddy waters I guess.
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Re: Duster disc brake conversion
[Re: Sniper]
#2722806
12/09/19 07:27 PM
12/09/19 07:27 PM
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Joined: Feb 2006
Posts: 608 TN
1DGEMAN
mopar
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mopar
Joined: Feb 2006
Posts: 608
TN
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I just did this on my 72 Duster If you want to change the bolt pattern you have 2 options buy new axles which have the BCE axle offset and use the BCE rear drums and backing plates or you can redrilll your A body axles use the BCE backing plates and the "front 10 inch drum" It works out perfectly. I had all these parts sitting around it cost me nothing and works great.
Real Men shift for themselves
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Re: Duster disc brake conversion
[Re: cdstl]
#2722841
12/09/19 10:37 PM
12/09/19 10:37 PM
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Joined: Sep 2011
Posts: 1,487 STL
cdstl
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OP
pro stock
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All good stuff guys. The plan is to get Dr. Diff axles and use the BCE backing plates and drums. There are a couple of guys locally that I can get the backing plates from and the drums run about $50.
1972 Cuda 340 4 speed, 2001 Ram CTD 4x4 6 speed, 1970 Duster 408 4 speed, 1996 Ram 5.9 2x4 auto, 1965 Coronet 500
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Re: Duster disc brake conversion
[Re: cdstl]
#2722862
12/10/19 01:18 AM
12/10/19 01:18 AM
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Joined: Jan 2003
Posts: 3,122 Auburn WA
Dave_J
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Auburn WA
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I was lucky when my mom gave me her 1974 Dart Swinger after the electrical fire. It was a /6 auto but had LBP all around. The rear end was a 7 1/4 open but had 10 X 2 1/2 drums. I ran that rear end when I took my Ford 9 inch out of my 65 Barracuda. One day it went BANG and was making a grinding noise like bearings so that is when I swapped my 8 1/4 Aspin rear in. The Aspin rear drums were 10 x 1.75. I then took the drums off my 7 1/4 to find the grinding noise was just the left shoe lining had come unbound. I had the 8 1/4 in the car so I just went ahead and put the big brakes on that axle, Backing plates and drums with new 'Leroy' kit and shoes.
Retired, US ARMY 1973-1994 ASE mechanic, Electrical 1994-1997 Retired GTE/VERIZON/FRONTIER 1997-2015
Posting cheap tech help (CRAP) here since Nov 97, 1000's of posts, some may be good.
03 Suzuki Burgman 650(Burger King) Scooter 65 Formula S Cuda 78 Little Red Express Truck 98 Buick Regal (wifes car)
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