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C&C swap from 14bolt rear headaches

Discussion in 'Differential & Driveline' started by 83chummins, Mar 6, 2019.

  1. 83chummins

    83chummins Full Access Member

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    Hey guys /gals i got a bit of pain in my neck from banging my head against the wall. So here is the deal. Im putting 37" millitary oz on 16.5 wheels my problem is the spring perches are too close to the hubs in turn springs wont fit with tires on. On the truck the spring perches are 42.5" c2c. On the dually axle they are 40.25 c2c but need to be some where round 38.5"c2c. With the frame being 34" wide im tryin to figure out if its goin to work out without moving the hangers etc wondering if anyone has done a swap from 14 bolt to c&c and made it work. Thanks in advance

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  2. HotRodPC

    HotRodPC Administrator Staff Member

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    Kinda got me lost here.
    So what do 37 inch tires have to do with spring perches? You doing an axle swap too? What do you have now? A single RW, Pickup Dually or a C&C Dually? And what do you have a for a donor going into what you have?
     
  3. 83chummins

    83chummins Full Access Member

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    Sorry i have a 77 srw 14bolt in the truck now. i went got a c&c drw axle from an 86 cal trans. Here is a pic
    [​IMG][​IMG][​IMG]

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  4. 83chummins

    83chummins Full Access Member

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    If i move the perch in further for the spring to clear tire safely it would put the spring perch c2c 38.5". The setup on the truck now is 42.5" c2c for the spring perch,but with the frame at 34 " im out of space for the spring hangers. Im trying to figure this out before i go for the swap so i can accomplish this in a day or two. Sorry if im not explaining this properly

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  5. 77 K20

    77 K20 Supporting Member Supporting Member

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    Most guys either get the wheels re-centered or run 2.5" spacers to get the tire away from everything.
     
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  6. 83chummins

    83chummins Full Access Member

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    Well i already have 2" steel wheel spacers that will go in between the wheels so recentering the wheel would be the best option? This is my first dually rear axle so im uneducated when it come to dually.

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  7. Big Chip

    Big Chip Full Access Member

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    I thought the cab & chassis dually rear was narrower than a regular dually or SRW rear end. Don’t quote me though but that may be your issue here.
     
    Last edited: Mar 8, 2019
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  8. QBuff02

    QBuff02 I like Big Blocks and I cannot lie

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    measure the difference in width between the wheel mounting surfaces on both axles. If I remember correctly, dual wheel axles use a different hub with more of an offset (moves the wheels farther inboard) than a single rear wheel axle. It's something like 4" narrower for a dual wheel axle setup. It might be as simple as swapping out the hub assemblies, that is if they are both full floaters to begin with. That will help cure being too narrow on the wheels, but it would still leave you with having to move the spring perches.


    Edit: Found a pic after a search, this is the difference in the hubs from a srw to a drw axle.

    IMGP1707.jpg
     
  9. 83chummins

    83chummins Full Access Member

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    The pic doesn't show up but I'll get a tape on it here after the first cup of coffee


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  10. 83chummins

    83chummins Full Access Member

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    63 1/4 from wms to wms

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    For the c&c dually
     
  11. 83chummins

    83chummins Full Access Member

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    Around 72" for the 14 bolt hard to get a straight measurements when it's still on the truck

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  12. QBuff02

    QBuff02 I like Big Blocks and I cannot lie

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    so now the question becomes, what to do about the missing 8.5" of "axle" between the one you have and the one you're wanting to put on. I've been researching putting a modern axle under mine, and in doing so have realized there are numerous differences between axles and wms widths and spring perch widths, shock mount orientation, etc. You could theoretically change hubs and drums and run your spacers to get back most of the missing 8", or find another axle that could be a more direct swap, with the same wms distance and probably for less time and headache as well. moving spring perches is one thing, but having to tear into all the "outboard" stuff can be a royal pain in the a$$..
     
    Last edited: Mar 7, 2019
  13. bucket

    bucket Super Moderator Staff Member

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    What is the end goal here? Are you trying to run H1 wheels as rear duals or something? What is the purpose in the crazy narrow rear track width?
     
  14. 83chummins

    83chummins Full Access Member

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    That is why I was banging my head last night on my fab table goin this is a shit show if I have to move hangers shackle etc...

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  15. 83chummins

    83chummins Full Access Member

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    Pipeline Welding rig.. don't want the back end to be 8 foot wide plus the short c&c rears hold more I think my fix is to offset the inner wheel 1.5 " to clear the spring pack

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