Rear disc brakes

Discussion in 'The whoa and the sway.' started by GStage1, Jul 21, 2004.

  1. GStage1

    GStage1 Always looking for parts!

    Has anyone ever tried to swap the rear disc brakes from a 76-79 Caddy Seville to a 68-72 Skylark/GS?

    Just wondering if you had any problems.
  2. GoldBoattail455

    GoldBoattail455 462 -> TH400 -> Posi

    Sounds like a good idea. And releatively easy to find a Seville. Hmmmmm.
  3. GStage1

    GStage1 Always looking for parts!

    Local yard has a couple of them and the Sevilles use the same bolt pattern as the Skylark/GS models, 4.75" bolt circle.
    Looks like an easy swap?????
  4. gobuick

    gobuick Silver Level contributor


    You can experiment on the GS you're building for me. I wouldn't mind a bit!

  5. GStage1

    GStage1 Always looking for parts!

    Ok, Frank, I will check into it on Sat. Looks like a simple swap. I will let you know what I find out and go from there! I will email you late Sat.
  6. Rick Henderson

    Rick Henderson Well-Known Member

    I did the swap. Followed the advice on the Buickperformance board. I brought the retainer plate to a local machine shop to have them to remove part of the lip, and they didn't bolt it down, causing it to be crooked.
    I ended up taking a die grinder bit and putting it on my drill press and removing the metal that way. I bolted it down to a piece of flat stock first.
    I can send you some pictures of the process. And the finished brakes if you like?
  7. GStage1

    GStage1 Always looking for parts!

    The reason I ask about the swap is the Seville seems to have the same 8.5" rear as the 68-72 Skylark/GS models and this seems to be a bolt on item. I will see on Sat what it looks like. The article on our site was written with the later model Camaros and Firebirds in mind. I have not seen many here w/disc brake rears. All 76-79 Sevilles have the disc brake rear.
  8. GS464

    GS464 Hopelessly Addicted

    How did this go? Sounds like just the ticket for us budget racers!
  9. GStage1

    GStage1 Always looking for parts!

  10. GStage1

    GStage1 Always looking for parts!

    Well, got the rear disc brake set-up from an 81 Seville (ones that have the "goofy" trunk, looks like they got rear ended and the trunk slants down at a 45 degree angle).

    Very simple to remove the set-up since the car is a front wheel drive. Basically there are 4 bolts with 15 mm nuts. Removed the calipers and then the e-brake cable. Took about 10 mins per side. The Skylark axle flange will have to be turned down to 6.125 for them to fit inside the rotors. Only item I see being an engineering challenge is the e-brake set-up. May contact the vendor listed above for some assistance. Will keep everyone posted on this issue.
  11. oPh

    oPh Well-Known Member

    Have used the late '78 & 79 Seville rear disc pieces on 8.5 A-body rears. Unlike c-clip rear disc conversions, one has to machine a small spacer to take up the slack between the stamped steel 4 bolt axle retaining plate & the National 712146 axle seal. Similiar spacer has to be machined if trying to do this with a bolt-in axle 8.2 rear.

    In reading above text, only the '77-79 models of the early Sevilles had rear disc, & all '77-79 sevilles had 5 on 5 bolt pattern axles & rotors. '76 sevilles were all drum brake rear with 4 3/4" bolt pattern. To adapt the '77-78 or late '78-79 Seville caliper mtg plates & calipers on earlier A-body rearends, one will need to use '79-81 T/A rear disc rotors.
  12. GStage1

    GStage1 Always looking for parts!

    Apparently someone has thought of this conversion and uses the more plentiful 80-5 Seville/Eldorado rear disc brakes which are the correct 5 on 4.75" bolt circle. The 79-81 Trans Am rotors will not clear the stock 15" rallyes.

    So, the listing on Ebay is for $139 for both sides, all brkts included. If this works, this is a cheap way to have disc brakes since the other parts should not cost more than $100. I already have the rotors, calipers, pads and ebrake springs from the salvage car.

    Here is the link on Ebay that Frank found!
  13. GStage1

    GStage1 Always looking for parts!

    I checked out his site and it is for the 8.5" corporate rears with bolt in axles. Once I have more info on this kit and install it, I will create an article on our site below. His site is very simple and here it is:

  14. jpoole

    jpoole Stage 1

    This is very interesting stuff. Can't wait for the ariticle.
  15. TomGS72

    TomGS72 Silver Level contributor

    I went down to Advance Auto Parts and bought everything for the rear of an 85 Riviera. A place called A&A Manufacturing (Dirt track stuff) makes brackets for the calipers. I have a 12 bolt in my car with Ford 9" ends. I had to modify the brackets, they are weld on brackets. They might have bolt on brackets, I can check. This was very easy to do. I just bolted the caliper to the bracket and put pads on and used air to compress the caliper to hold in place to get a good tack before welding.

    Tom Jenkins
  16. GStage1

    GStage1 Always looking for parts!

    As soon as I get the kit, I will let you know. Buying the stuff new/rblt at auto parts store is expensive. There are many, many of the 80-5 Seville, Eldorado, Tornado, Rivieras in the local yards w/rear disc brakes.

    From my parts prices checks, here is what I found, rotors were $50, calipers were $50 w/50 core. Local yard charged me $50 for calipers, rotors and brkts. So, as soon as I can get this installed there will be a detailed article. This looks to be a much cheaper way for disc brakes than some kits priced at $500-700.
  17. rootman

    rootman New Member

    In the back of the new hemmings muscle car there is a story and parts list for gm axles or ford 9in
  18. GStage1

    GStage1 Always looking for parts!

    Well, I found a better set-up.

    Uses thicker caliper brackets and larger rotors which would match the front ones. No axle flange maching is required.
    Looks like the kit will run about $320. I think Frank will order a kit and I will do the installation in the next month. Will keep everyone posted on this swap.
  19. gobuick

    gobuick Silver Level contributor


    I placed the order this morning with Skip. He said the parts should ship today & will arrive in Florida by next Friday or the Tuesday after Labor Day.

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