A body disc brake conversion info????

Discussion in 'The whoa and the sway.' started by 71Skylark1384, Dec 1, 2016.

  1. 71Skylark1384

    71Skylark1384 Platinum Level Contributor

    Thought I'd pick some of yall's brains. (not sure if that is proper english:puzzled:)
    I've got a set up including disc brakes, calibers and spindles. Below are some pics of what I have and the numbers on it. Now next question is; can this set up be a direct change from the front drums I have or do I need something else? I do have the brake booster on the car already.

    Thanks, :TU:
    David

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  2. knucklebusted

    knucklebusted Well-Known Member

    What is it off of? I would need to see the back of the rotor to see the spindle. If it is off any other GM A-body from 68-72, it will mostly likely work. You might also want to grab the proportioning valve and the master cylinder.

    I've done this swap several times and it is a great bang-for-buck swap.
     
  3. 71Skylark1384

    71Skylark1384 Platinum Level Contributor

    Not exactly sure what year, but I did get these from another member here who has a 68 skylark. I believe I have a master cylinder. but I am not familiar with a proportioning valve.
    Here is a better view of the backside
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  4. knucklebusted

    knucklebusted Well-Known Member

    Those look like 73 or newer one piece spindles. They definitely will not bolt on. You will have to have different upper control arms and probably special lower ball joints and it will mess with your bump steer. I would not consider this a good option unless you do more research on the parts.

    The proportioning valve is usually either right under the master cylinder or mounted on the frame. The brake lines from the master will go to it and then disperse to the front and rear wheels. It is usually also where the wire for your brake light goes.
     
  5. 71Skylark1384

    71Skylark1384 Platinum Level Contributor

    Ok. Thanks you very much. And when you said it came off a 73, do you mean a A-body car?
     
  6. knucklebusted

    knucklebusted Well-Known Member

    I can't tell from the images. If the bolt pattern is 5x5, they would be B-body spindles.
     
  7. 71Skylark1384

    71Skylark1384 Platinum Level Contributor

    Still trying to figure out more about theses, knucklebusted had great info, but still trying to figure more info about the disc brakes as I plan on selling these.

    Thanks.
     
  8. nekkidhillbilly

    nekkidhillbilly jeffreyrigged youtube channel owner

    you need a dual bowl mc and the porp valve fyi
     
  9. BrianTrick

    BrianTrick Brian Trick

    I run the B-body spindles with the Hotchkis uppers. I'll get all my info out and list all of the part numbers. See if that is what you have.
     
  10. LARRY70GS

    LARRY70GS a.k.a. "THE WIZARD" Staff Member

    Brian,
    That includes a different lower ball joint as well, correct? Converts the front end to negative camber gain for much better handling as well?
     
  11. BrianTrick

    BrianTrick Brian Trick

    Yes,a special lower ball joint.Actually a production ball joint that is remachined to fit the A-body lower A-arm. The outer tie rods are G-body/F-body for the 70-older,and the 73-77 A-body tie rods for 71-72. B-body spindle with 88-92 Camaro 1LE 12" rotor.
     
  12. BrianTrick

    BrianTrick Brian Trick

    Here are all the numbers that I have:

    78-96 B-body spindles,LH #18016023,RH #18016024

    88-92 Camaro/Firebird 1LE rotors #18016035 You can also use the B-body rotors,if you redrill for the smaller bolt circle.

    Lower ball joints for the factory lower A-arms,GM # 9767113 or Moog #K6145 *These will need to be machined to fit* or Hotchkis #1155 direct fit.

    Outer tie rods: 64-70 will use 80's F-body & G-body tie rods,71-72 will use 73-77 A-body tie rods.

    Calipers: B-body calipers,stock or Police.

    Due to the location of the spindle,this will lower your car about 3/4",and move the wheels outboard about 3/8".

    You can also use early Camaro/Firebird spindles,but the rotors are smaller,so you aren't making as much of an improvement.

    Hotchkis and Global West makes tubular lowers for the B-body spindle swaps. Hotchkis #1104B for traditional coil springs,Global West #CNR-42H for coilovers.
     
  13. 71Skylark1384

    71Skylark1384 Platinum Level Contributor


    Great info, but where are the numbers located at? There are a bunch on these, but none that I had seen that matches the part numbers you mentioned. As I am not entirely sure what this set up came off of.
     
  14. 87GN_70GS

    87GN_70GS Well-Known Member

    When I google 3963991 and 2, i get that these are F-body spindles?
     
  15. LARRY70GS

    LARRY70GS a.k.a. "THE WIZARD" Staff Member

    Could very well be. My first Buick was a 1972 Skylark. Back then, there was a company called HO Enterprises. They marketed a kit to fit F body spindles (late 70's I believe), into the 64-72 A body. The kit consisted of special upper and lower ball joints, and tie rod ends. The spindles were taller, and they altered the front end geometry. In the normal A body, as the suspension compresses, the wheel camber goes POSITIVE. The tire tilts out at the top. This is significant since in a hard turn, the OUTSIDE wheel suspension compresses as the car leans, and the more it compresses, the more positive the camber becomes. That is the single biggest reason for the large amount of under steer of 64-72 A bodies. Sway bars help by limiting suspension compression on the outside tire, less compression, less camber change. The camber change results in the tire rolling onto it's sidewall lessening it grip, and increasing slip angles. There were two problems inherent in the the F body spindle retrofit. One, the upper ball joint angle was extreme, and two, it frequently resulted in a very thick shim pack to align the car properly. These days, both of those problems were fixed with new upper control arms marketed by several suppliers today. I believe Global West was the first.

    The taller spindle alters this. Instead of positive camber gain, you get negative camber gain. As the suspension compresses, the wheel camber goes increasingly negative. The tire stands up straighter in a corner, and the handling and road grip is DRAMATICALLY improved. It was night and day in my 72. So much so, that I wound up taking my rear sway bar off as the car would get tail happy when pushed into a corner, especially with power applied. The front stuck down that good.

    I would definitely look into using those spindles. You'll need different caliper hoses as well for the F body calipers.

    I don't want to derail this thread, but if anyone is interested, I can post a Musclecar Classics article from December of 1987 entitled "Get a Grip". It goes into more detail about HO enterprises and the spindle swap.
     
  16. wovenweb

    wovenweb Platinum Level Contributor

    I'd be interested in seeing that article.
     
  17. LARRY70GS

    LARRY70GS a.k.a. "THE WIZARD" Staff Member

    OK, let me try posting it here. See if you can read it. GetaGrip1R.jpg GetaGrip2R.jpg GetaGrip3R.jpg
     
  18. wovenweb

    wovenweb Platinum Level Contributor

    Thanks!
     

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