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12 bolt question

Discussion in '1973-1991 K5 Blazer | Truck | Suburban' started by CarolinaBogger, Apr 5, 2001.

  1. CarolinaBogger

    CarolinaBogger Registered Member

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    Do the 12 bolts use 1330 series u-joints? And what modification would I have to make to my driveshaft if I wanted to put a 12 bolt in place of my 10 bolt setup?

    CB
     
  2. ftn96

    ftn96 1/2 ton status

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    Dude, dont quote me on this, cause I'll get gang banged in here, but Im am almost certain that they use the same u-joint.

    Will work for beer, parts and tools.
    90 Jimmy 350TBI-700R4-241-33" BFGs-10 bolts w/4.10's
    <A target="_blank" HREF=http://www.nashvillek5.freeservers.com>http://www.nashvillek5.freeservers.com</A>
     
  3. ftn96

    ftn96 1/2 ton status

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    Same as the 10 bolt that it. Again I think so.

    Will work for beer, parts and tools.
    90 Jimmy 350TBI-700R4-241-33" BFGs-10 bolts w/4.10's
    <A target="_blank" HREF=http://www.nashvillek5.freeservers.com>http://www.nashvillek5.freeservers.com</A>
     
  4. dyeager535

    dyeager535 1 ton status Premium Member

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    Ok, now maybe I'm totally misinterpreting the question, and the gang bang rule applies (make a mistake and its gonna happen lol) but on my truck, with 10 bolt axles, and a 1976 K5 driveshaft (so should have been from a 12 bolt) the 12 bolt used SMALLER u-joints. I had to buy an adapter u-joint to use the 10 bolt/12 bolt shaft.

    However, the "yoke" that retains the driveshaft to the rear axle should be interchangeable. So if you just swap the 10 bolt yoke onto the 12 bolt it should work with no other mods. FWIW, the driveshaft that came with my SM465/205 combo out of a 1976 Blazer, had the correct length when I used the 10 bolt axles.

    Dorian
    My K5 and Chev/Olds tech/links page: <A target="_blank" HREF=http://www.dorianyeager.com/index2.html>http://www.dorianyeager.com/index2.html</A>
     
  5. Wheels

    Wheels 1/2 ton status

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    It all depends on what yoke you have in the 10 bolt versus 12 bolt. I have a 12-bolt rear and a 10 bolt front, both use 1310 u-joints.
     
  6. Emmettology 101

    Emmettology 101 3/4 ton status

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    It all depends on what 12 bolt you have actually. Some have a small u-joint(smaller that a rear 10 bolt.. But their are some that have a larger u-joint, the same size as the 10 bolt..

    You can either buy a conversion u-joint that is about $22 a pop or you can take the Yoke off of your 10 bolt and get a 10 bolt seal and put the 10 bolt yoke onto your 12 bolt... It is that simple(may have to double check on the seal, but the 10 bolt yoke definately works on the 12 bolt)


    <font color=green><A target="_blank" HREF=http://emmett.coloradok5.com>http://emmett.coloradok5.com</A></font color=green>[​IMG]
     
  7. dyeager535

    dyeager535 1 ton status Premium Member

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    Interesting. just called the parts store, and had them look up the pinion seals for an '86 K5 (10 bolt) and a 1976 K5. Two different part numbers. No alternates listed.

    Surprising to me...maybe thats why my new yoke (smaller than the original 10 bolt one) is leaking!? Not leaking much, anyone know what the diameter is of the two off the top of their heads? : ) I have the 10 bolt one out, I'll have to measure it. Odd.

    Then again, can't trust the parts places, they listed a 1974 350 as having a different water pump than a 1983 350, but the pumps they brought up, were externally identical as far as I could tell.

    Dorian
    My K5 and Chev/Olds tech/links page: <A target="_blank" HREF=http://www.dorianyeager.com/index2.html>http://www.dorianyeager.com/index2.html</A>
     
  8. Emmettology 101

    Emmettology 101 3/4 ton status

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    My bro did the 10 bolt yoke swap onto his 12 bolt... He got the info from a local rearend place. If I remember, i will ask him tonight and see if he remembers what the part number or app was for the seal...

    The Blazer 12 bolts all had the small yoke, where as the trucks and heavier apps ahd the larger one.


    <font color=green><A target="_blank" HREF=http://emmett.coloradok5.com>http://emmett.coloradok5.com</A></font color=green>[​IMG]
     
  9. dyeager535

    dyeager535 1 ton status Premium Member

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    Ok, that info would be good to have..not going to be able to rip mine apart yet again for a few days. The yoke I got supposedly came off a 70's Camaro, so that makes sense about the smaller yoke. The straps to retain the u-joint are also necessarily smaller.

    Dorian
    My K5 and Chev/Olds tech/links page: <A target="_blank" HREF=http://www.dorianyeager.com/index2.html>http://www.dorianyeager.com/index2.html</A>
     

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