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v1500 axle swap

Discussion in '1973-1991 K5 Blazer | Truck | Suburban' started by basketcase, Dec 28, 2005.

  1. basketcase

    basketcase Registered Member

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    I just bought a rotbox 84 k20 for parts for my 90 v1500 sub, besides the axles what else needs to be changed? the k20 has been sitting for about 4 years because of brake problems, so i don't think i should reuse any of those parts.
    Any one know what axles that k20 should have under it? I got the truck for 500 bucks with a working plow and the 350 will turn over by hand, so i guess it was an ok deal.
     
  2. MTBLAZER89

    MTBLAZER89 3/4 ton status GMOTM Winner

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    Beside the axles what else do you want to change? You can take pretty much everything from that truck and put it under your sub. If you mean what else do you need from the truck to swap the axles? You will need the spring plates and U-bolts for the rear axle, and thats about it. You will need a converion U-joint for the rear axle. Part # 447 at Napa. The pickup should have a 14BFF in the back and a 10B up front.
     
  3. basketcase

    basketcase Registered Member

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    do i need the master cylender from the k20 for proper braking with those axles?
     
  4. b454rat

    b454rat 1/2 ton status Premium Member

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    The axles aren't really much better than what you got now. inless it is the HD3/4 ton, it will have a 14 semi float in it. The front is the same what you have now, just 8 lug. Actually, the front in your truck now is better than the 3/4 ton. IIRC, 88-91 have 30 spline inners than the older 28 spline.
     
  5. MTBLAZER89

    MTBLAZER89 3/4 ton status GMOTM Winner

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    No you don't need the MC for proper braking. If you convert the rear to disk brakes then I know some people swap out MC's for bigger ones, but I run the stock one still. It seems to work well. b454rat is right about the front axle. The older ones are 28 spline vise the 30 spline ones you have now. Stronger a "little" but the 28 splines are way more common so it's easier to find spares. I still think a 78 should have a 14B full floater not a SF, but that is pretty easy to tell just look at the rear wheel for the big hub stickin out through the center of the wheel
     
  6. 89GMCSuburban

    89GMCSuburban 1/2 ton status

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    There's a super easy way to ID the axles...use the axle ID in the Technical page and let us know...

    Don't need the 3/4 ton MC, mine locks up the 36's with the 1/2 ton cylinder.
     

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