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Hot Rods Narrowing a 40? style rear end

Discussion in 'The Hokey Ass Message Board' started by steve hackel, Jan 11, 2018.

  1. steve hackel
    Joined: Mar 5, 2010
    Posts: 208

    steve hackel
    Member

    Hello; I tried a search, but how you ask the question in the search box determines the answers you get.... I struck out. I currently own a 34, and am thinking to replace the rear end with a 40, but the 40 is wider than the 34 so can it be narrowed, and if so - how? I currently am running widened 16" Kelseys on the stock 34 rear, and they pretty much fill the wheel opening just inside the fenders lip, so a wider rear end will cause them to hit. How does one narrow the housings and then how would you go about shortening the axles? I have some ideas, but I would appreciate any feedback or links to any previous posts. Thanks
     
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  2. Jim Lato
    Joined: Jun 4, 2017
    Posts: 488

    Jim Lato
    Member

    im doing the same with my nova, putting a 63" ford 9" in but it needs to be shortened so this would be a good topic to gather some information for this. i have struck out of luck with places around here as well. especially doing it where the axles and tube are welded back true, im assuming the axles would have to be custom ordered to length?
     
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  3. Cosmo50
    Joined: Sep 8, 2011
    Posts: 210

    Cosmo50
    Member
    from California

    The banjo rear end is very different from your typical 8" ford or 10 bolt chevy. The spider gear is part of the axle and the outer end is tapered with a keyway. I believe the tapered end is heat treated for strength. So you wouldn't be able to just cut it down to length. Similar to a regular axle, the splined ends are treated so you can only cut them down so much. For the banjo, you would have to find axles and tubes from a 34 or that are the correct length. You could also do the axle conversion to have regular 8" axles with pressed on bearings with the banjo center.
     
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  4. alchemy
    Joined: Sep 27, 2002
    Posts: 15,677

    alchemy
    ALLIANCE MEMBER

    Why replace the 34 rear with a 40? Other than the brakes there is no benefit. It is not stronger. And if you just want the juice brakes they will bolt onto the 34 rear with no adapters needed.
     
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  5. Pete Eastwood
    Joined: Jul 27, 2011
    Posts: 935

    Pete Eastwood
    Member
    from california

    Agreed. There are gear ratio choices available for the '34.
     
  6. gimpyshotrods
    Joined: May 20, 2009
    Posts: 17,378

    gimpyshotrods
    ALLIANCE MEMBER

    Yup, scratching my head here.
     
  7. steve hackel
    Joined: Mar 5, 2010
    Posts: 208

    steve hackel
    Member

    Ok guys, please don't shoot the messenger here.... Not knowing the answer to something actually means "I DON'T KNOW THE ANSWER TO SOMETTHING!" :confused: :D :D :eek: I never knew that a 34 rear end was just as strong as the later years, and just always assumed that they were, based on what years were being used on the cars that were continually being built and shown in magazines. So, in making that assumption (incorrectly) I was just working up a future build sheet for my coupe; 8ba motor, T-5 trans, F-250 front brakes & buick drums, a "stronger rear end" etc, etc !
    So, if I wish to build a strong / solid 34 style rear end,, what other modifications and parts would I need to perform & acquire in order to do this? Your help & understanding is greatly appreciated. :rolleyes:
     
  8. gimpyshotrods
    Joined: May 20, 2009
    Posts: 17,378

    gimpyshotrods
    ALLIANCE MEMBER

    It's all good, brother.

    Earlier banjo axles (non V8) have two bearings on the pinion gear. The pinion head is hanging out there, unsupported

    Later banjo axles have three bearings on the pinion. The first two are like the earlier axle, and the third is past the end of the head, taking the pinion out of single-shear, and putting it into double-shear. Other parts are stronger than earlier models, too.
    IMG_20180111_213116.jpg
    Yeah, I have the books, that far back.
    [​IMG]
    If you still are not convinced that a design from 1932+ is strong, here is my banjo, it is 8-years old.
    IMG_20171230_142819.jpg
    It is a few years old. See the family resemblance?


    Add juice brakes, and drum safety retainers.
     
    Last edited: Jan 11, 2018
  9. Tim
    Joined: Mar 2, 2001
    Posts: 11,229

    Tim
    Member
    from Raytown Mo

    It would seem the most common breaking point with the banjos is axle keys. Some guys remedy this by running skinny bias plies that will never hook up enough to brake anything and other have a second key way machined and fitted to double the strength.
     
  10. And still others apply the proper torque to the axle nut so the load is carried by the taper.

    Charlie Stephens
     
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  11. gimpyshotrods
    Joined: May 20, 2009
    Posts: 17,378

    gimpyshotrods
    ALLIANCE MEMBER

    Exactly. I have a feeling that this is why so many keys were broken, while others never did. Proper torque is absolutely essential.
     
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  12. alchemy
    Joined: Sep 27, 2002
    Posts: 15,677

    alchemy
    ALLIANCE MEMBER

    Steve, you do realize the difficulties of using an open drive transmission with the early rearend, right? You will need to buy/make an open drive conversion that removes the torquetube, then replace the strength that the torquetube had by upgrading the wishbones somehow. Lots of guys will just add another bar triangulating the original bars, and use a new attachment point up front. But here is the only place the 34 is weaker than the 40: the radius rods are scrawnier.

    If you really want an open drive banjo rearend, I would recomment finding a 35-6 rearend and buying the open drive conversion for that. The radius rods/wishbones on a 35-6 are stronger, and used with a triangulating bar should hold up just fine for a flathead powered car. And I think the 35-6 rearend should be a good width under your full-fendered car.

    Check out http://www.hotrodworks.com/ for open drive conversions and triangulating bars.

    Many guys will just grind the top of the 35-6 spring to fit into the original 34 crossmember (34 has curved spring, 35-6 is straight)
     
  13. steve hackel
    Joined: Mar 5, 2010
    Posts: 208

    steve hackel
    Member

    Yes, I've since been in contact with the Hot Rod Works, and their answer is a combination of most of the above; start with the 34 axle housings, then add a 39 + up center section with the corresponding ring & pinion, find the carrier with 11 tooth spider gears & matching center + fixture, and then send it all into them for a modern conversion that will still utilize the 5x5.5 bolt pattern, any Ford Hydraulic brake system, new modern 28 splined axles and a machined center to accept all of this in one near package. I had previously done this with an A' rear end and also a new KiWi quick change rear end from New Zeeland, and their work is beyond fantastic, so I might just end up at their door once again.
     
  14. cody1958
    Joined: Sep 19, 2006
    Posts: 828

    cody1958
    Member
    from wichita ks

    What did all this cost to do
     
  15. 19Fordy
    Joined: May 17, 2003
    Posts: 6,860

    19Fordy
    Member

    Cody asks a good question. What your doing doesn't sound inexpensive.
     

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