Rear disc brakes for a GM 10 bolt 8.5, True-false or maybe ?

Discussion in 'The whoa and the sway.' started by BWINN519, Jan 27, 2014.

  1. ilikebmx999

    ilikebmx999 Well-Known Member

    I've started on an ls1 rear brake conversion on my 12 bolt. Picked up backing plates, calipers, brackets and brake lines from an 01 firebird. Bought new rotors and pads. Used the original backing plates as a spacer to center the caliper bracket over the rotor. Looks like a 3/8-1/2" spacer would be needed to run stock 15's. I'm still in the mock up stages. I nabbed the brackets for the parking brake cables and I think I'll mount them similarly on my axle (lower control arm mount).

    [​IMG]

    This is before the backing plate spacer
    [​IMG][​IMG]

    Still need to clean these up and smooth them out a bit
    [​IMG]
     
  2. Buick 72

    Buick 72 Well-Known Member

    Looking good. How are you dealing with the axle retainers? If I remember correctly the aluminum LS backing plate would have to sit outboard of the axle retainer to maintain acceptable axle end play. This offsets the LS backing plate by the thickness of the stock axle retainer which then leads to the rotor not centering in the caliper abutment. Yours looks like it lined up nicely though.

    The other thing to look out for is the rubber boot around the e-brake mechanism. It was pretty flimsy new and most are torn or worse. You can see it in the last picture. When I last looked, they did not sell this rubber boot separate from the LS baking plate. (Dorman makes one that is incorrect so beware.)

    Robert
     
  3. ilikebmx999

    ilikebmx999 Well-Known Member

    This is a C clip 12 bolt axle.

    Yea that boot is ripped up on both but not super concerned about it. If I come across a set of plates with good boots at a yard I'll pull them at the yard.
     
  4. Buick 72

    Buick 72 Well-Known Member

    Cool, the C-clip style is practically a direct bolt on. For the boot, it may be worth checking around since its been a while since I needed any. I would think they would start making a replacement boot sometime.

    Good luck with the install.
    Robert
     
  5. ilikebmx999

    ilikebmx999 Well-Known Member

    I've seen some home brewed fixes like this [​IMG]
     
  6. knucklebusted

    knucklebusted Well-Known Member

    So, you are going to run factory Buick chrome wheels on this setup? I'd love to see how that turns out.
     
  7. ilikebmx999

    ilikebmx999 Well-Known Member

    That is the plan for now. I plan on a 17 or 18" setup but pretty low priority on the list as of now.
     
  8. ilikebmx999

    ilikebmx999 Well-Known Member

    Quick update, to run stock 15x7 rally wheels I'd have to run a 1.25" wheel spacer which would get close to the fender lip but would still clear. I guess I'll be buying new wheels sooner than later.

    Also ended up buying new e brake boots for $17 on eBay.
     
  9. knucklebusted

    knucklebusted Well-Known Member

    I was afraid of that. As much feedback as people like me and I'm sure others have given them, you'd think they would add "will not fit factory Buick 15" Chrome Wheels!"

    Got to drive it yet? Stop on a dime and give you a nickel back? You can grind on the caliper some to get a little more clearance and maybe run a much smaller spacer.

    I managed to change to different rotors with taller hats, turned the rotors down to exactly 11", moved the caliper bracket to the other side of the car and mounted it on the inside instead of outside after slotting the holes to drop it closer to axle AND removed the shim on the outside brake pad. With all that I managed to run Buick wheels with only a 3mm(1/8") spacer. It looks pretty factory. With Wheel Vintique wheels, I was able to take the spacers out.

    I'm going to try the scarebird brackets on my next go around on my 71 350 car.
     
  10. ilikebmx999

    ilikebmx999 Well-Known Member

    Haven't driven it yet. Lots of other things I'm buttoning up and need to get a new driveshaft made.

    I'm fine with getting new wheels and not running the rally wheels. Too narrow anyways.
     
  11. HotWired

    HotWired Well-Known Member

    do your brackets work on the 8.2 bolt in axles like whats in my 68?
     
  12. RACEBUICKS

    RACEBUICKS Midwest Buick Mafia

    yes they do
     
  13. 87GN_70GS

    87GN_70GS Well-Known Member

    What did you do for a proportioning valve?
     
  14. ilikebmx999

    ilikebmx999 Well-Known Member

    I have an adjustable.
     
  15. HotWired

    HotWired Well-Known Member

    cool ill give you a call tomorrow
     

Share This Page