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Technical How Hard Can It Be?? - V8 Banjo to A Transmission

Discussion in 'The Hokey Ass Message Board' started by brett4christ, Apr 24, 2019.

  1. I'm going to try to keep my banger/A-trans in my '31 Tudor, but I want to install juice brakes. I have roundback spindles and complete '40 brakes for the front, so I'm (relatively) good there.

    My dilemma is, 1) do I install the '40 backing plates on the A banjo, 2) do I install the '40 banjo and adapt the torque tube to the A transmission, or 3) do I install the '40 banjo and convert to open drive? Can the A transmission be converted to open drive?

    1) is what the Model A Touring guys do, but it seems like a ton of work to make everything fit and not rub or interfere. And to do this, I would need access to a mill or lathe to clearance the backing plates and drums. My Les Andrews book covers what needs to be done.

    2) makes the most sense to me. I would have to fab/modify spring perches for a spring-over, and would have to shorten/modify the torque tube/drive shaft to fit the A transmission. Any advice here would be great! (Hint, hint!)

    3) could be a benefit IF the A transmission can be adapted. Drawback would be that I would need a torque arm to control axle wrap (what little a banger would have).

    2) and 3) are attractive in that I also have a Halibrand Culver City 201 center and cover...not much else. But I can use most of the '40 banjo guts to fill up the 201 and install new bearings.

    WWHD? (What Would HAMBers Do?)
  2. adam401
    Joined: Dec 27, 2007
    Posts: 2,436


    For option number one all thats needed is an angle grinder to clearance everything. Your not turning down machined surfaces or anything. Ive done it. Its more than fine and its easy.

    How about this as yet anither ootion to fuck yer head up. Run a 32 transmission that will bolt up to the 4 banger bell housing with a 40 rear end with shortened torque tube. This I havent done but have been looking into. Boom, mind blown. Problem solved.
    raven, patmanta and dana barlow like this.
  3. Thanks @adam401 , but if I have to buy a trans, I'll be in search of a T5 and an AA bellhousing.

    You're right...I had to read that 4th option three times to finally understand! o_O
  4. Bruce Lancaster
    Joined: Oct 9, 2001
    Posts: 21,682

    Bruce Lancaster
    Member Emeritus

    The problems of adapting a V8 torque tube to an A trans or using a V8 trans against your A rear involve about 5 bolts
    You simply remove the inner and outer U-bolt cover and swap them for the other kind. They are identical except for bolt spacing, and since the parts are common and cheap swapping is the universal route over drilling and tapping.
    Basic numbers 4513 and 4520 in the pictures. U-joints interchange '28-48, choose the tightest one you can find.
    Rare early Model A U-joints had riveted instead of forged construction...all hands agree that these should be buried upside down in a crossroads at Midnight.
    Simplest route is just use the A rear. It is actually quite likely to survive, and if it fails you have lost nothing but a handful of gaskets and some paint.
    Moriarity and adam401 like this.

  5. @Bruce Lancaster , so you're a proponent of just installing my '40 backing plates onto the A rear?
  6. Tids32
    Joined: Jun 2, 2009
    Posts: 12


  7. Atwater Mike
    Joined: May 31, 2002
    Posts: 10,596

    Atwater Mike

    Use the '40 backing plates and drums on the 'A' rear. To get away from drums dragging on backing plates, buy shims for the rear 'A' tapered axles. (we used to cut steel beercans and wrap them to the axle keys. Trim to fit. Paper pattern is easier, then cut the shims to the patterns.) Torque axle nuts to Model A specs.
    Model A axle tapers are NOW to V8 'specs'...
    Methinks LES ANDREWS is taking you on a longer walk than previously mapped out.
    cactus1 likes this.
  8. I just posted this up on another same question post. Ya don't need a mill or to grind anything.

    Personally I try to think for myself and keep it simple. Yes, first gen hyd brakes (39-48) will mount on a Model A rear axle and work just fine. I did mine just a bit different. I didn't want to mess with the issue of Spring perch and wheel cyl. so I swapped sides and turned backing plates 180* and put things together. Been just fine for 15 years. I was even able to hook up the E-Brakes. Look close and you'll see the brake line connected on the Bottom of the plate. I even used my Stock A mounted pedal to operate the 39-48 master.

    The Wizzard
  9. Then of course there were some other Questions and here is my follow up.

    @Pist-n-Broke How hard was it to bleed the rear cylinders? Did you have to do anything out of the ordinary to bleed?

    Brett; I've been hammered to death over the years (70+of them)for my way of looking at things. Ya see I believe hard parts don't have a clue what they are mounted to or how they are even mounted. They will just do what they are intended to do the best they can. In the case of the bleeder valve on the bottom I simply trusted the Law of Physics in that solids will travel down and air will travel up, and it works. It did not involve any Voo-Doo or out of the Ordinary technique to get er done. Once bled the best one can do it there just may be a small dot of air left behind. I think if there is it will also find it's way out and up to the Master being it is mounted above the wheel cyl's. At any rate I have a very solid pedal and good working brakes. Were they not, Id be looking to change something till they were. Stopping is very important!

    The Wizzard

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