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'88-up PU owners

Discussion in '1992-Present Chevy & GMC models' started by dyeager535, Dec 11, 2001.

  1. dyeager535

    dyeager535 1 ton status Premium Member

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    \'88-up PU owners

    Some general AND specific questions for any of you that own these trucks. (88-02 I guess now!)

    What year were rear disks first offered on the 1/2 tons?

    Has the rear axle ring gear diameter changed?
    I noticed the other day a couple of trucks that had what appeared to be 8.5" diffs, but the lower "triangles" on either lower side of the center section were different a bit. (not 7.5" vs 8.5", part of the "triangle" was missing on these)

    What I'm trying to do though is find out if the rear axle flange has changed since '91. If it hasn't, I'm suspecting the newer 1/2 ton rear disks to be a straight retrofit, but I don't know anyone that has one of these trucks with rear disks, so I can't compare.

    What I *really* would like someone to do is compare two trucks with 10 bolts (81-91 vs 88-up w/disks) side by side, to see if the backing plate bolt pattern and/or flange is the same or changed. I am pretty sure you can see this from underneath the vehicle, with nothing taken apart. Even a digital picture of the disk rear brake vehicle flange from underneath would probably get me started...

    Thanks!


    Dorian
    My tech/links page: <a target="_blank" href=http://www.dorianyeager.com/index2.html>www.dorianyeager.com/index2.html</a>
    Why insist on counting when the ring gear has the tooth counts stamped in?
     
  2. Wheels

    Wheels 1/2 ton status

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    Re: \'88-up PU owners

    Hey Dorian,
    I'll check my 2001 (10-bolt) against my 79 (12-bolt) and get digital pics for you.
    Larry
     
  3. dyeager535

    dyeager535 1 ton status Premium Member

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    Re: \'88-up PU owners

    Pics would be nice, at least of the 12 bolt. Been awhile, I appreciate the response. Heres what I posted to the other board as a follow up:

    Ain't gonna happen easily : (
    Had the chance to crawl under one last night, and measure the axle flange vs my '86 10 bolt. 2000 has a 3.5"x3.5" 4 bolt pattern, the '86 has a 3"x3.5" Axle flange is rotated 45 degrees, but that probably wouldn't matter much.

    Looks like plenty of clearance to run a 15" wheel though, if you wished. E-brake comes off the rear of the backing plate, so it loops forward over the axle.

    Appears you couldn't just re-drill the backing plate, (bolt holes would be too close together) but perhaps with some grinding of the edge of the axle flange for the slightly different bolt pattern, and a plate custom made to bolt to the back of the stock '86 flange, plus two additional holes in the "adapter plate" for the wider disk brake backing plate bolt pattern, it would bolt up. Sounds like a lot of work though, unless some company mass produced them. On top of that, the e-brake cable would then point at the ground, or straight up, which might cause some problems as well.

    Perhaps some of the trucks 88-up were still using the same flange? Anyone know when rear disks were first offered? If GM made the disks for the "earlier" flange pattern, it might be a direct swap. I did notice that the "triangles" on the lower edge of the diff housing on the newer trucks, has been changed, but that probably doesn't indicate anything.

    Now I'm thinking a 3rd gen camaro might be a good donor. (82-??) They could have rear disks, and the cars are plentiful. Not sure how big the rotors are, but I'm thinking even if they are smaller than D44 or 10 bolt rotors, they would still work as good, at least, as rear drums.


    Dorian
    My tech/links page: <a target="_blank" href=http://www.dorianyeager.com/index2.html>www.dorianyeager.com/index2.html</a>
    Why insist on counting when the ring gear has the tooth counts stamped in?
     
  4. Wheels

    Wheels 1/2 ton status

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    Re: \'88-up PU owners

    By chance I also have a 98 Camaro that has rear disc and a 2001 Burb that looks like the Z71. I'll look and see tonight. Had class late last night.
     
  5. Twiz

    Twiz 1/2 ton status

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    Re: \'88-up PU owners

    I would think you would need the axle shafts too. Because they might be different length for the disk brake.

    I'm not sure If you know this, but the rear disk brakes use a drum-brake for the parking brake. It's not like the
    the old style rear disks (thank-gawd) where they used the caliper as a parking brake too.

    You might want to check out the S-10 blazers. Still a 10-bolt (7.5) I'm not sure if it's addaptible.

    *Don't hold me to this*
    -'99 and up silverado have rear disk
    -'98 ish S-10 have rear disk

    The basic 10-bolt didn't change, they added a drain-plug to the diff houseing.

    Just guessing, I'm not really sure, I don't think the swap would be very easy. Probably alot more work than a A.M. bolt-on kit.

    <font color=white>.</font color=white>Eric
    <font color=white>.</font color=white>Twizted
     

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