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14 bolt swap problem

Discussion in '1973-1991 K5 Blazer | Truck | Suburban' started by FatBoyBlazer, Jan 20, 2002.

  1. FatBoyBlazer

    FatBoyBlazer 1/2 ton status

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    i did a 14ff swap from a 10 bolt to a 14FF out of a one ton(not 3/4 ton) i had to move the spring pearches.......when i had the brakes adjusted the drive shaft would lock up in certain positions.......only when on a lift when it is on the ground its fine..another problem is that the little straps that hold the u-joint to the yoke of the rear end were really loose and i know that i tighened them.......any one ever have this problem before?? also its a 1991 blazer with a 4 inch BDS lift with all new springs

    hola
     
  2. 87superblaze

    87superblaze 1/2 ton status

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    regarding the u-bolt straps, did you buy a new U-joint for the 14 bolt swap. The 14 bolt uses a much larger diameter bearing than a 10 bolt. This would cause your straps to be loose no matter how much you tighten them. I am not sure what to tell you about the driveshaft lockup.
     
  3. Greg72

    Greg72 "Might As Well..." Staff Member Super Moderator

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    Is the pinion angle a LOT different than with the old 10-Bolt? If the pinion was rotated UP excessively, your driveshaft slipjoint might be all the way IN.... that might be why it's binding.

    Just a thought....

    I'm about 2 weeks behind you. My 14-Bolt is in the garage, but not ready for the install yet. [​IMG]



    -Greg72

    '72 K5 Blazer - 427BB/TH350/NP205/6" Lift/35x12.50's
    <font color=blue>See it here: </font color=blue><a target="_blank" href=http://coloradok5.com/gallery/albun38>http://coloradok5.com/gallery/albun38</a>
     
  4. 1bigk10

    1bigk10 1/2 ton status

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    When on the lift you're lifing from the frame right? Causing the springs to droop and that 14ff is a lot heavier than that weeny 10bolt this may be causing your yokes to bind up at the t-case???

    1982 K5 Silverado. [​IMG] 327 SHPE powerplant SM465/205,15"custom lift 38.5"TSL/SWAMPERS 12boltrearD44 front,3.73 gears.
     
  5. rodzzilla

    rodzzilla 1/2 ton status

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    Did you put a conversion U-Joint in? Or change the driveshaft? The 1ton has a 1350 joint, where the 1/2ton is a 1310. Just a thought since you did not mention it.
     
  6. POFF

    POFF 1/2 ton status

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    The snout on the front of the 14 bolt is longer as well. Your drive shaft is probably to long. Have it checked and fitted with the correct yolk.

    '70 K-20 San Diego, CA
    I know, I can't spell!
     
  7. Eric M.

    Eric M. 1/2 ton status

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    I had the same problem with my 1 ton after lifting it. The driveshaft would bind when on a lift (holding truck by frame, suspension at full droop). My CV joint was binding. Check your U-joints and / or CV joints for binding when in this position. I was able to do a little grinding and the problem was fixed. I don't think drive shaft length would be the cause, at full droop the distance from the rear dif. and tranfer case is greater than while sitting loaded. If the shaft bound up at droop due to being too long, you'd probably shove it right into the transfer case when sitting loaded.

    The answer at the top seems correct regarding U-joint straps being loose. Make sure you have the right combination of yokes and U-joints.

    Let us know what finally fixes the problem. I'm very curious.

    Eric M.

    Blown K3500 [​IMG]
     
  8. FatBoyBlazer

    FatBoyBlazer 1/2 ton status

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    I got the Hybrid U-joint frm NAPA #447so i think its the rght u-joint....any other sugestions

    hola
     
  9. ZZ4x4

    ZZ4x4 1/2 ton status

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    Ok , I got one for you. This happened to mine. The NAPA u-joint is the greasable type with a zerk in the corner. The u-joint must be pressed into the driveshaft with the zerk facing outward or it will contact the driveshaft when spinning at more than a 5 degree angle (or so). May want to check this. Good luck. JT
     
  10. FatBoyBlazer

    FatBoyBlazer 1/2 ton status

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    i'm gonna try that tomorow

    hola
     

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