Rear drum brake upgrade?

Discussion in 'Suspension, Steering, Brake & Wheel Topics' started by 67johnny, Dec 9, 2020.

  1. 67johnny

    67johnny Veteran Member

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    Hey all.
    Looking for a 1 inch wheel cylinders as an upgrade for my 70.
    Anyone have a part number?
    Thanks.
     
  2. BigBlock73

    BigBlock73 Veteran Member Lifetime Gold Member

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  3. JUNKYARD AUTOCROSSER

    JUNKYARD AUTOCROSSER Member

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    As you probably know, your camaro came with 7/8" wheel cylinders which I upgraded to 15/16" wheel cylinders from a 70's era chevrolet station wagaon. I tried installing 1" wheel cylinders, but I couldnt get it to fit. Either the housing was too big , or the bolt holes did not line up. Cant remember. I also installed some 3rd gen finned aluminum drums which is lighter, dissipates heat faster, and reduces brake fade. Another improvement was to install Andy Portifield RD4 brake shoes. These shoes are used for classic car road racing and are great. I also installed a rear brake proportioning valve to fine tune the balance of drums with the stock front disks. I also upgraded the front brakes , but thats another story. Take care.
     
    BonzoHansen and camaro71/holland like this.
  4. camaro71/holland

    camaro71/holland Veteran Member

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    This. I used the bigger cylinders from a xx El Camino. Also, when you buy a set of brake shoes, you get a longer and a shorter one for each side. By two sets and use the longer ones only. Balance front/rear with an adjustable valve.
     
  5. kenny77

    kenny77 Veteran Member Lifetime Gold Member

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    My 77 has 15/16 on there stock. They changed them to that bigger size in 76
     
  6. 67johnny

    67johnny Veteran Member

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    Thanks for all the great responses and input !
    Will look into those 76 wheel cylinders.
    I do have a proportioning valve on the car now.
    I am a little curious about matching the brake shoes with the longer ones.
    I can see that this would add more frictional surface area, have just never been down this road.
    How does that play into the leading shoe theory?
    Thanks.
     
  7. JUNKYARD AUTOCROSSER

    JUNKYARD AUTOCROSSER Member

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    I am not an expert on drum brakes, but I do know that brake shoes come in pairs. Each pair has a side with a longer/larger friction section and a shorter side with a smaller friction surface. If you purchase two sets of shoes, you can combine the longer/larger friction on one wheel discarding the shorter/smaller sections. This allows you to have a total larger friction surface for each wheel. I have read that this improves drum brakes performance. It does make sense. I have also done this on my car, but I cannot quantify the improvement. I do these things because as an autocrosser I am always trying to maximize performance. I dont believe it is necessary for normal street driving. There is no problem matching the larger friction surfaces together. They fit fine on my car.
     
  8. 67johnny

    67johnny Veteran Member

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    I think I will give the larger shoe trick a try.
    Was surprised to find out that riveted shoes were hard to find.
    Not a fan of the bonded units in high heat applications!
     
  9. BonzoHansen

    BonzoHansen Administrator Lifetime Gold Member

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    I run these as well
     
  10. Ihada70Z28B4

    Ihada70Z28B4 Veteran Member

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    This is a popular trick for the Turbo Buicks to hold a few more psi at the line. I've done it, it worked with no adverse effects.
     

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