small bolt pattern to big bolt pattern

Brakes for your Classic Mopar

  1. Miami Dolphins

    Miami Dolphins El Diablo

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    1971 Demon 340 4 speed, no power brakes drums all around, want to convert to big bolt pattern and stay with drum brakes. What is involved and where is the best places to get the parts...salage yards, auto parts etc.

    Thank you.
    El Diablo.
     
  2. Oklacarcollecto

    Oklacarcollecto Life is an experiment

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    There was never big bolt pattern drum brakes used on the front of the Mopar A-bodies.

    Adapters would be your only option.
     
  3. grassy

    grassy Well-Known Member

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    ...adapters..
     
  4. Miami Dolphins

    Miami Dolphins El Diablo

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    so all of the drum brake mopars are small bolt?
     
  5. Oklacarcollecto

    Oklacarcollecto Life is an experiment

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    All the Mopar A-body front drums are small bolt pattern. When the big bolt pattern came out on A-bodies they were all disc brakes.
     
  6. hemi446

    hemi446 Well-Known Member

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    I think the only way you could put big bolt pattern drum brakes on the front would be if you could use early B-body front spindles and drum brakes set up off a Road Runner or Charger. Just a thought
     
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    • Miami Dolphins

      Miami Dolphins El Diablo

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      is the spacers that you are referring to; are those going to give the look like if the tires are sticking out of the wheel well. Don't care for the doughnut type of appearance on a car.
       
    • Oklacarcollecto

      Oklacarcollecto Life is an experiment

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      Good quality billet adapters are about 1" thick. If that bothers you then you can make that up by using a wheel with a 1" deeper backspace.
       
    • DoctorDiff

      DoctorDiff Well-Known Member

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      You can install B/E body front drum brakes if you run '73-'76 A-body lower ball joints and upper control arms (or my upper ball joint tapered adapters).
       
    • Furious65

      Furious65 C-body Guy

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      You can also have the hubs and drums drilled for the bbp.
       
    • mopar jimmie

      mopar jimmie Mopar Jimmie

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      Just about any drum barke spindle will work as long as you change the upper control arm to the big ball joint type. There is also another option , you can use the DR DIFF ball joint adaptor that allows you to use the small ball joint in the big joint spindle , i used these on a swap and they worked well .
       
    • Dartnut

      Dartnut Don't hate me because i'm beautiful

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      Just curious, why don't you want bbp front disc brakes?
      It's an easy upgrade and i bet parts are cheaper than the old drum brake stuff.
      You also get much better braking with a lot less fade......
       
    • river rat

      river rat Well-Known Member

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      why go thru all the trouble and not go with disk brakes?
       
    • Oklacarcollecto

      Oklacarcollecto Life is an experiment

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      I am with you there because of part prices.

      I looked up a brake drum for a 1969 B body and it was $113.99 for the 10". The 11" was a little higher.
       
    • Miami Dolphins

      Miami Dolphins El Diablo

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      I'm thinking I would have to add a power brake booster and all that goes with that.
       
    • Oklacarcollecto

      Oklacarcollecto Life is an experiment

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      No need to change or add a power brake booster. The factory offered power and non-power brakes. Master cylinder (about $20.00) and a proportioning valve (about $65.00) if it doesn't come with the disc brake set up.
       
    • cudaman51

      cudaman51 Well-Known Member

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      the right way to do the rear axle is buy new axles with the big pattern.Then you will need complete B body brakes because none of the old brake parts will work. Some people drill the old axles for the large pattern but the studs would be close to the outside of the axle flange if you want to risk it.
       
    • 70 DUSTER CRATE

      70 DUSTER CRATE Well-Known Member

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      These guys are giving you good advice.
      What ever you do, it's a pain in the butt ! Better get the big picture before you make a move.

      It's gonna cost ! Don't add it up !

      New brakes, new MC, new axles and with which bearing, new tires, new rims, NEW, NEW, NEW, and NEW !
      Who's going to install ?
      It's only MaMaMoneeey ! But it's worth it !
      Just kidding ! It's the Best thing I ever did to my car. After 40 years, it was time to upgrade and I think it paid off.
      I had front discs, Kelsey Hayes, had the rotors re-drilled.

      Got the Summit rear disc conversion.

      Bought the regular moser axles, not race, a lot cheaper and 90% as good, so it's plenty good, with the green bearings and long studs, installed free on them by Moser, through Summit, with free shipping.

      Talk to DR. Diff, and see what he has, is my suggestion.
      He might have everything you need, except for rims and tires.
      He might have a package deal.

      After I found out about him, I bought my universals and drive shaft from him.
      Take your time! The type of rear axle bearing you use might determine the brake system you use.
      When money doesn't come easy, I thought I was never going to get done with the rest of the car, but it's getting there.
       
    • Dartnut

      Dartnut Don't hate me because i'm beautiful

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      I have manual bbp a body disc brakes on my Dart Sport, check out my build thread.
      They are definitely stiffer with more pedal effort than power brakes, but they are not too bad at all.
      I have a '69 Valiant with the same set up and they are the same as the Dart Sport as far as feel and function go.
      Power brakes were an option on '73 and newer V8 a bodies except 360 cars ('74 and up) and 340 cars ('73 only) which were standard equipment. If you ordered power brakes on a '73 and up a body, you automatically got the good bbp disc brakes up front and bbp rear end with the bigger rear brakes, even if it was a slant six car. Manual brake slant six cars always had sbp 9'' drum brakes.
      After Jan 1st 1976, all a bodies had bbp disc brakes on them and bbp rear ends of course.
      Bbp rear ends came in 7 1/4'' or 8 1/4'' in these years ('73 and up), but the 8 1/4'' rear end came standard on 340 and 360 cars. Sure grip was optional on all cars.
      In my opinion, the a body cars '73 and up were much better in the braking and steering department than '72 and older cars. Heavier duty.
      And parts for them are easier to come by and cheaper to boot, a win win situation......
      This is some info if you are looking for a donor car or wanting to make an upgrade.
       
    • 2 Darts

      2 Darts A-body Addicted

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      X2 IMO, disk brakes would be a better use of $s.
       
    • Dartnut

      Dartnut Don't hate me because i'm beautiful

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      Good advice here, i would strongly recommend Dr.Diff (Cass is his name) for someone who knows his stuff and is willing to talk to you about your needs. His prices are good, and he ships right away. I bought some gears off of him for my Dart Sport, and they were good quality and shipped fast.
      I talked to him on the phone for about 1/2 hour, and he won't steer you wrong.
      He is even a member on this site!
      His user name is Dr. Diff (go figure!) :supz:
       
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