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10 bolt and 12 bolt differences

Discussion in 'The Garage' started by chvymudin3388, Sep 30, 2006.

  1. chvymudin3388

    chvymudin3388 1/2 ton status

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    every freaking rear end ive found has 3.08's ive found two 12 bolts both 3.08's. whats the differencs between a 10 bolt and 12 bolt if i get the 12 bolt is it gonna bolt in place? is the ujoint different? backing plates? i need to know all the differencs that might keep me from doing this swap
     
  2. dremu

    dremu Officious Thread Derailer Premium Member

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    U-joints are different, IIRC ... one is 1310 and the other is S44, maybe?

    As long as they're both off Blazers (1/2 ton trucks, Burbs, whatever) the perches will be the same, shocks should be.

    Backing plates ... I donno. I suppose if they both had the same size brakes you'd have a better chance ... why not just get one complete, drum-to-drum?

    -- A
     
  3. NoReGrEtS

    NoReGrEtS 1/2 ton status

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    they both suck, you want to find a 6 lug 14bsf or swap to 8 lug and get a 14bff
     
  4. pauly383

    pauly383 Daddy383 Staff Member Moderator

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    Early ones had smaller rear drum brakes . But you can use your existing brakes . When my 10 bolt broke , we undid the backing plates ( after axle removal ) and suspended my brakes above the axle , slid new axle under , and attached my brakes without even opening a a fluid line at all . No bleeding :thumb:

    Had to do the conversion u-joint for awhile . Have a new shaft now thats already set for 12 bolt on the axle end , and 10 bolt joint cv on transfercase end .

    I took the axle itself off a 2wd truck , and the 5 lug shafts slid out and 6 lug shafts slid right in . The shock mounts are a little off I noticed with the shackle flip I have , and one shock has to be upside down to clear tube .

    I have a 4x4 12 bolt now , changed the other 12 bolt out to go with lower gears , well a little lower . Went to 3.73's over 3.08's , but hey it was dirt cheap. Now I have 4.56 to go on the 3.08 axles ( put under my project ).
     
  5. BL1TZKRIEG

    BL1TZKRIEG 1/2 ton status

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    how much stronger are the 12b compared to the 10b ?
     
  6. pauly383

    pauly383 Daddy383 Staff Member Moderator

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    Not much if at all . Its a trade off , smaller pinion for 12 bolt with bigger ring gear , larger pinion for 10 bolt with smaller ring gear . I like either axle up to 35 or so with open carriers and lockrights . Its all about finesse , they can live for a long time . Most of the broken ones you hear about are either beat on , too damn old , or have new gears/diffs installed and not broken in right :thumb:
     
  7. jdemaris

    jdemaris Registered Member

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    Info on semi-floating 14 bolt cover rear?

    I'm looking to beef up the weight carrying capacity on my 83 K5. Does anyone out there have the load-carrying ratings for the different axles? My K5 has a Chalet motorhome on it - so when loaded an it has an extra 1300 lbs. - at least - all of the time. It now has the 10-bolt cover, 3.08 rear. I'm thinking of taking the rear out of an 89 3/4 ton Suburban that's up in my field and putting that into the K5. It has a 14 bolt cover, 12 bolt ring gear - called the "9.5" by GM - with 3.73 gears and much larger brakes. I checked part numbers for axle-bearings and they are different - so I assume bigger and better for more weight. The axle weight rating tags are missing on the Suburban - but even if it had the tags they would depend on the spring-package.
    It looks like it will be a bolt-in swap - but I'd like to know the different weight ratings for the 10 bolt, 12 bolt (14 bolt cover), and the larger 3/4 unit with full-floating axles - themselves - not accounting for the springs.
     
  8. dyeager535

    dyeager535 1 ton status Premium Member

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    The apps with big 13" brake 14SF (the 9.5") is rated over 8000#GVW, but there is no difference between it and any other 14SF. You can do a search for a thread started by me and titled "14SF tech" for a whole bunch of info on it.

    Only one I know off the top of my head.
     

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