Chevy 12 bolt with 9 inch ends

Discussion in 'Got gears?' started by BuickRacer69, Dec 3, 2018.

  1. BuickRacer69

    BuickRacer69 1320, Mark of the Beast


    I have a Chevelle 12 bolt under my Skylark. It currently is a stock housing with aftermarket C Clip style axles. I was going to cut off the housing ends and have a chassis shop weld new ones because I think my housing is slightly bent and this should correct it. I also want to switch to a bolt it style axel. Would I bet better off welding on a stock style 12 bolt housing end and using an aftermarket C Clip eliminator, or should I weld on a 9 inch end? If I use the 9 inch end will it work with my brakes, and do they make a bearing that will work with a "stock" 12 bolt axel or will I have to buy new axles? Any suggestions would be appreciated.

    Thanks and have a good day,

  2. BrianTrick

    BrianTrick Brian Trick

    First,if your housing is bent,I would make sure it can be fixed,or is usable,before investing any money into it.
    As far as housing ends go,the Moser #7900 is all you need. It allows you to have a true bolt-in style axle,and has the same bolt pattern for the GM brakes/backing plates. This housing allows you to run a large Ford sealed bearing,or a Timken SET20 tapered roller. No need to put the wrong ends on and convert to Ford brakes,when you can keep what you have.

    Attached Files:

    300sbb_overkill likes this.
  3. monzaz

    monzaz Jim

    Also another thing is What are you doing with the rear?
    How did you find out the housing was bent? How bent is it? 1/8", 1/4" More????
    As Brian said see how far a problem this is.
    We have built some housings with some tweak to the ends not being true. If you have to really force the axles into the housing that is TOO MUCH you will need to repair the rear -

    I have straighten quite a few...BUT they re is not a guarantee they will stay ...sometimes metal has a memory when it get bent... I disclaimer the fixing of rear end housings.

    If your going to run the rear hard install the 7900 Moser ends if you 1/8" off or less you should be able to weld them on and it will be true to the center section as long as the shop gets it right.

    Any more than that you have to straighten that tube or ditch the housing.

    If you do use the 7900 ends you will have to hog out the backing plate center register hole to get the larger (FORD / Pontiac /olds 9508B moser part number which is 3" + bearing Outside diameter ) so it can slide through the backing plate register into the housing flange end.

    When you get your axles PAY FOR the access hole in each axles ...Makes life alot easier to install your axles with the drum brakes installed.
    Another thought if you going this route and you want to ungrade your Posi and axles to 33 spline.
    Then to if you ever want to just race and minimal street time you can install a FULL RACE spool.
    If you keep all your posi parts (shims and races) with the posi unit you can just swap it back in the next year if you want to go street bound more again.

    Good luck if you need help with parts I am sure Brian or I can help you order what you need.

    J D
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  4. Bens99gtp

    Bens99gtp Well-Known Member

    if the tubes are bent are 12 and 10 bolts able to be retubed????
  5. monzaz

    monzaz Jim

    I am sure they can be they were built that way... BIG money and as is people just doing ANY kind of labor these day s if not happening... let alone specialized labor like
    I would say a Moser, Currie, Strange, place like that can do it...Bring out the wad of CASH though.... :)
    I would say strange will not touch it... Currie either...Moser might give it a whirl...Maybe.

    Money better spent on a NEW rear.
    ONLY if the housing is a super rare deal would I even think about it. Something that is going to make a 100K show car yah maybe.

    J D
  6. BuickRacer69

    BuickRacer69 1320, Mark of the Beast

    Thanks for the advice, the Moser #7900 is exactly what I was looking for. Next step, see how bad the housing is.

    Thanks again for you advice,

  7. BuickRacer69

    BuickRacer69 1320, Mark of the Beast

    If I use the Moser 7900 ends, is there a bearing that will work with my existing axels or would I also have to switch axles? My existing axels are Moser 33 Spline C Clip axels.
  8. BrianTrick

    BrianTrick Brian Trick

    You will need new axles.
  9. monzaz

    monzaz Jim

    Well there might be a conversion axle that slide into the ford OD and 1.40 inner diameter. Maybe a c-clip elim bearing might work...Thise are just bearings inside of the aluminum blocks. I will do some measuring. Call Moser too Jim
  10. BrianTrick

    BrianTrick Brian Trick

    Jim is correct. They offer two different c-clip eliminator bearings. Two different ID’s. It depends on what you have now. They usually don’t have a shoulder to press the bearing against.
  11. monzaz

    monzaz Jim

    Shoulder... Yes but if you buy Moser race axles and elim kit those axles do not have shoulders either. I do a lot of c-clip elim race stuff here and order the axle spool and elim kit ...kits. These elim bearings must have a tighter press than the standard bolt in axle bearings or the step is just for stupid proofing the install of bearings in the general public repair world. I feel more warm and fuzzy with e machined ledge too... But as stated i do nt believe it is totally necessary with the elim bearing being used and you could put a light tact after install to the outer side of the shaft...NOT WELDING the bearing to the axle shaft.... just tact the axle so the bearing can not go any further if you ever need to remove it will not be welded on.
    BUT we have to see if the bearing exists... :) Jim
  12. BrianTrick

    BrianTrick Brian Trick

    You are correct. They just take a c-clip axle and put the eliminator kit on it. As long as you know where to stop,and the bearing can’t move,it should be fine. Pressing the bearing too deep could cause issues with your brakes. If you are running traditional drums,you could bottom-out the drum and bind on the shoes or backing plate. It’s got to be spot-on with rear discs,or you will end up shimming something.
  13. monzaz

    monzaz Jim

    ALL the specs are in the c-clip elim kit. You just press on till the measurement is correct ... YOU JUST need a I have done plenty and really never had any issues with the distance ... it is like anything once you do something enough you get comfortable with it and it becomes second nature. Just like setting up a GM rear then throwing a 9" in and you get the pinion depth backwards because the shim is in the housing and not under the
  14. BrianTrick

    BrianTrick Brian Trick

    You would be surprised on what people have brought me to fix. Or maybe not.
  15. monzaz

    monzaz Jim

    Oh I Know what you mean. Especially stuff that was suppose to be REBUILT...LOL. Right.. .

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