1965 AFX Coronet brakes

Brakes, Steering & Suspension

  1. funnykarman

    funnykarman Well-Known Member

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    I want to put 11x3 inch drums and shoe assembly from a 65 Monaco . My Coronet has an altered wheel base and that puts a lot of the weight on the rear wheels . My thoughts are on the back spacing on the backing plate . On one of my 10x2.5 backing plate looks not as deep as the 11x3 ones . I would like to stay away from disk brakes on the rear . Thinking back to the afx cars that ran back then a lot of them used only rear brakes and spindle mounted wheels up front . So anybody know if this would effect the axles when they are ordered ?
    Thanks John
     
    Last edited: Jan 12, 2021
  2. mobileparts

    mobileparts Well-Known Member

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    John,
    If you figure out on how you are to proceed -- you will need Rear 11" x 3" backing plates --- and that will be difficult --- Police Car, Ambulance, and Heavy Duty Rears are your best bet ---
    I have the +++ N.O.S. +++ Asbestos Brake Shoes, Rear Wheel Cylinders, Rear Brake Hardware --- Combi Kits and Self Adjuster Kits, and Rear BRAKE DRUMS,
    to take you the rest of the way.....
    As per forum rules (how dare I be up front and honest !!!! And give you my phone number !!!!!),
    P.M. me, when you have procured backing plates....

    Yours, Craig.....
     
  3. funnykarman

    funnykarman Well-Known Member

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    Thanks Craig , I have a set from a Monaco I parted out years ago . It was one with a four speed and a 426 wedge . If you have a rear backing plate for a 11x2.5 shoes , measure it on the back with a straight edge down to the axel flange on the outside and see what you get . Mine was 2 inches . I will get back to you on the rest of your parts . Thanks John
     
  4. funnykarman

    funnykarman Well-Known Member

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    OK guys do me favor , if anyone has a loose backing plate for a 10x2 or 10x2.5 rear brake . Put a straight edge across the back of the plate and measure down the edge that bolts to the housing and let me know what you come up with . My backing plate I have measured
    2" . Just trying to figure out what mother mopar did to make up the diff. on 2" to 3" shoes , deeper backing plates or longer axles . Thanks John
     
  5. mobileparts

    mobileparts Well-Known Member

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    FYI --
    There is NO 10" x 2" Rear Shoe in the MOPAR World.

    "A" Body Rears are 10" x 1 3/4"
    "B" and "E" and even "C" body small block are
    10" x 2 1/2" Rears
    "B", "E", and "C" 383s, 440s, etc.all use 11" x 2 1/2"
    Rears...
    The 11" x 3" Rears after 1964 were ONLY on
    Police Cars, Ambulances, and a special ordered Heavy Duty Rear End (Towing package, for example)
    ------ From the Factories -----
     
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    • funnykarman

      funnykarman Well-Known Member

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      I just need a measurement for the spacing on the backing plate . The ones I have did come from 1965 Dodge Monaco that came from the factory with a 426 wedge and a four speed . It had a sure grip in it . I have no problem with my brakes on the front of my 65 coronet I am just going to rebuild them with all new parts . I have a Dana 60 for the rear but have the question as to what the backspacing for the Monaco backing plates are . Did Mopar make to different backing plates for the two different shoe sizes . Thanks John
       
    • funnykarman

      funnykarman Well-Known Member

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      Ok , no 2 inch shoes in the mopar world . Looking on rock auto shows 2.5 shoes for the coronet with /6 and 426 as the same shoe . What I am asking is how the off set from the 11x3 inch and 10x2.5 shoe is compensated for . Was it a different backing plate or what was it ? Here are several pics of the rear brake backing plate and drum I saved from the 1965 Monaco I parted out . It had a 426 wedge and a 4 speed with trac lock . Most parts listing state used in heavy duty vehicles . With the weight of the Monaco and its hi-po drive train they used the bigger brakes . So first pic shows 3 inch shoes , pic2 shows 11 inch drum and pic 3 shows the back of the backing plate with a straight edge across it and being measured , showing 2 inches . I cannot find my other stuff I need to measure . So can some one do the measurement on a backing plate that is off and let me know what you come up with . Thanks John DSCF0860.JPG DSCF0862.JPG DSCF0861.JPG
       
    • khryslerkid

      khryslerkid FBBO Gold Member FBBO Gold Member

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      Try post #24 on how to measure your 11" backing plates. Plenty of info on a Google search.

      From the post...

      "To measure the backing plate offset you want to set the backing plate flat on a bench. You'll need to hang the bottom 1/3 of the backing plate off the edge of the bench so that the mounts for the e-brake cables don't keep the backing plate from sitting flat. It isn't much, but they do change the measurement. Then, measure from the bench to the top of the backing plate through the center hole (for the axle) in the backing plate.

      If you get ~1.75", you have 11x2.5" plates. If you get ~1.5", you have 11x2" plates. Those I know for sure, as I've measured them. I don't have a set of 11x3" backing plates, but the math would say you'd get ~2" measuring them as I described above. This is because half of the additional width is on the inside of the axle flange and the other half is on the outside to keep the axle flange in the same spot, as there was only one axle offset for BBP 8 3/4 axles.

      img_2848-jpg-1714942228-jpg.jpg

      Also, if you have a set of 10" backing plates without any hardware, shoes etc you can measure those to determine if they're BBP 10" backing plates or SBP 10" backing plates. BBP plates will measure 1.75", they're 10x2.5" and have the same axle flange offset as the 11x2.5" brakes so you get the same measurement. The SBP 10" backing plates will measure roughly 1.25"

      https://www.forabodiesonly.com/mopar/threads/converting-rear-drum-brakes-from-sbp-to-bbp.372527/

      The width of a drum is measured at the running surface for the shoe, inside the drum. Width of a drum is the diameter of the inside.
       
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      • funnykarman

        funnykarman Well-Known Member

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        Thanks Kid , that is what I was looking for , the backing plate I have is for a set of 3 inch shoes and is deeper than a 2.5 backing plate . I am going to run a set of Mosier axles with green bearing and needed to verify it . again Thanks John
         
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        • 1danc

          1danc Active Member

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          My 65 Coronet, I took a complete setup of 11x3 brakes off a New Yorker[66 ?] donor for my original 8-3/4 rear , everything bolted right on, no issues whatsoever , I did a relo of leaf springs and had wheels built to offset I wanted but making the brake change didn't affect the position of the axle flange in any way - it was easy , your backing plate attaches to housing & drum will sit on axle flange as any size would - unless you have some other clearance issue I'm not understanding ? the wheel is going to sit on that same spot where the drum slides over the studs regardless of the brake size - if I'm missing something let me know,for real ! The complete assembly should be inside the wheel unless you have the wheels sticking out past the body panels w/ offset [not good for alot of reasons] - Monaco parts should be fine / donors are a great way to go, I did my front disc conversion from a [72 Charger ?] Spindles out, all bolt on but needed to move rubber hose mount position @ frame - love to see the car @ some point, I'm a big fan of the AWB / MAXIES - I went Max/ Convertible [almost talked myself into all 3 , another day maybe - LOL I have an R/T I've been sitting on while helping friends on their projects & it's been poking at my brain
           
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          • Fran Blacker

            Fran Blacker FBBO Gold Member FBBO Gold Member

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            Bought a Dana 60 out of a 67 GTX 4 speed had 11x3's.
             
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            • 1danc

              1danc Active Member

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              Cool, give it a good once over, since you have it out and you'll be moving up to serious HD - good luck
               
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