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Anybody know which 12 bolt .....

Discussion in '1973-1991 K5 Blazer | Truck | Suburban' started by Krase, Oct 27, 2002.

  1. Krase

    Krase Registered Member

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    Can anyone tell me what 12 bolt rear axle is out there that will mount directly up to my 88 blazer without having to move the spring perches or any other major work. Really just looking to getting one i can just swap out for the shot 10 bolt on it now. Oh and i would like to keep the same number of lugs if possible as I can only afford the axle right now.
     
  2. Shaggy

    Shaggy 3/4 ton status

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    <font color="green"> All twelve bolts are 6 lug, and pretty much any one that you find in a 73 or later truck or Blazer will bolt right in. </font color>
     
  3. 4X4HIGH

    4X4HIGH 1 ton status Premium Member GMOTM Winner

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    NOT ALL 12 bolts are 6 lug. I had a 71 chevy truck that was a factory 5 lug 12 bolt. Yes about the years though, anything 73 and later will bolt right up except you may have a u-joint issue to deal with but thats only a conversion joint needed.
     
  4. bigjbear

    bigjbear 1 ton status Staff Member Moderator

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    All 4x4 12B are 6 lug. The '73 &amp; up 2WDs are 5 lug. The old 2WD were also 6 lug but are not bolt in for your truck.
     
  5. Rolled

    Rolled 1/2 ton status

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    Krase

    I just did the swap the other day. I have an 87 though.

    The 12 came off a 78 burb.

    Differences:

    1. Brakes = smaller than the 87 - I switched them over

    2. E-brake cables were different - Cured with brake switch

    3. 12 bolt yoke sat back about 1.5 inches further to the rear than the 10 bolt did. I needed to get the driveline lengthened anyways because of the 4 inch lift.

    4. Yoke has smaller ujoint than the 87 - I got a driveline off a 77 burb and am having it cut down with my 87 front yoke welded on. I'll have 2 different size u-joints but it was the cheapest way to go since I needed to lengthen my drive line anyways.



    Everthing else bolted right up - even the brake backing plates bolted right up.


    Good Luck
     
  6. Shaggy

    Shaggy 3/4 ton status

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    <font color="green"> Damn, sorry about that, I pretty much just think in terms of 4x4s. /forums/images/graemlins/rolleyes.gif </font color>
     
  7. fr8train

    fr8train 1/2 ton status

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    I have two 12 bolts one from a 2wd truck with 6 lugs and 4wd w/ 6 lugs. 2wd has got the smaller brakes 2.5" x 9" and smaller ferrule ebrake connectors.

    The 4wd version is bigger the axle tubes are bigger, brakes 2.75" x 11", and the larger ferrule ebrake cable.

    Ujoints still same. Spline count same. Yoke same.
     
  8. R72K5

    R72K5 Banned

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    truck 12 bolt brakes are all 11x2 std and 11 5/32 x 2.75" HD like in the big 10's and heavy half's, there are no 9" brakes on truck 12 bolts, 9" are car brake size on 10 bolts

    oh and yes the 70 and oldr 2wd all had 6 lug on 5.5" pattern and 7/16" studs and the leaf 2wd were 42.5" spring packs centers and will bolt under 73-up trucks but you gotta move one shock mount is all, this goes for 63-72 trucks with G70 leaf type rear(optionally available before 73) and 72 older U bolt setup is different than 73-up pickups burbs blazers(not heavy vans) in that the U boilts point downward and use a cast iron cradle type plate for the u bolt nuts mounted under the axle tubes




    good luck
     
  9. 87sm465np208

    87sm465np208 1/2 ton status

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    i did the 12 bolt swap, yep driveshft got slightly shorter, i didnt have it lenghtend tho, brakes were a bolt in from my 87, it was all good, just make sure its the right gear ratio. i got mine for free /forums/images/graemlins/smirk.gif.

    /forums/images/graemlins/usaflag.gif /forums/images/graemlins/truck.gif
     

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