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Technical Leaf Spring Issue

Discussion in 'Traditional Hot Rods' started by nonipshere, Jul 2, 2021.

  1. nonipshere
    Joined: Feb 20, 2012
    Posts: 146

    nonipshere
    Member

    View attachment 5106170 View attachment 5106170 View attachment 5106170 View attachment 5106170 View attachment 5106170 View attachment 5106170 View attachment 5106170 View attachment 5106170 View attachment 5106170 I used a Model T leaf spring on a Model A frame and attached it to a 1947 Ford Truck rear. The shackle mounts are adapters that bolt to the two top holes of the backing plate mount. I measured the shackle mount hole center to center and they are 51". The Model A shackle holes center to center are 50", so I had to stretch the spring more than normal to make it fit. This left me with shackle mounts that have very little to almost no angle when not under a load. (see pics) What are the consequences?
     

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    Last edited: Jul 2, 2021
  2. Malibu406
    Joined: Nov 10, 2020
    Posts: 223

    Malibu406
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    My observations are based on a visual of the geometry, not direct experience. Seems to me this isnt good as the dog bone could go eitherway. Down it could jam against axle housing. Since there is no angle to start rotation it could tend to jam or lock up horizontally then rotate making it inconsistent or notchy. My guess is the angle piece extension is a limiter?, but that wont engage either. I wouldnt feel comfortable running this set up.
     
  3. Mr48chev
    Joined: Dec 28, 2007
    Posts: 31,010

    Mr48chev
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    When I expanded that dinky ass picture it was too fuzzy to see the details clearly.
    I've said it before, If you want good answers give us good photos to look at so we can determine what we are looking at.

    I'd say that you pretty well answered your own question though. The perch either isn't the correct one or it is mounted wrong. I don't know if there is any difference between the truck axle width on that what appears to be a 46/47 pickup banjo rear axle tube and one from a car from the same time frame but that is something to check.
    Also why would you not cut those spring pads off and grind the tubes off before painting it?
    T spring (2).jpg
     
    X38 likes this.
  4. nonipshere
    Joined: Feb 20, 2012
    Posts: 146

    nonipshere
    Member

    The picture was fine when I dowloaded it. I can see it clearly. Must be on your end. The perches exactly replicate the perches on a model a rear. As for the spring pads, they're insignificant to the overall aesthetics of the chassis.
     

  5. Mr48chev
    Joined: Dec 28, 2007
    Posts: 31,010

    Mr48chev
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    You didn't show the full size image and the image is of such poor quality in resolution that we cannot expand it to study it. This is what we are seeing and if you want actual help give us something we can actually see. Hamb leaf spring issue.png
     
  6. Mr48chev
    Joined: Dec 28, 2007
    Posts: 31,010

    Mr48chev
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    That by the way is is on my 20 inch monitor and not on one's phone.
     
  7. MoePower
    Joined: Jul 12, 2004
    Posts: 226

    MoePower
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    from Omro, WI

    I am by far no expert and I'm sure some with more knowledge will chime in, but I would be inclined get some weight on the chassis ie engine, transmission, body etc before changing things around.

    From the pic it appears you only have the rear axle and the full spring pack attached to a bare frame, so very little weight for the spring to support.

    When I started my frame I only used the first two leafs of the rear spring to determine ride height. Once I drop the engine, trans, body and all the heavy stuff on I'll put the rest of the leafs in. With only the frame weight on the main leaf or maybe the second leaf you may find your shackles will sit at a proper 45° angle.

    Also when you pull the full spring pack, measure the height where it meets the rear crossmember. Then when you remove all but the main leaf, make up the difference with a wood block. This should get you in the ballpark of actual ride height.

    Like I said I'm no expert but I did stay at a Holiday Inn Express last night. :)
     
    Last edited: Jul 2, 2021
    trollst likes this.
  8. Happydaze
    Joined: Aug 21, 2009
    Posts: 1,291

    Happydaze
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    I'd also suggest getting some weight on the frame and work from there. This weight can easily be simulated with a couple of heavy duty ratchet straps / tie downs. Should cost less than the beer you'd need to entertain some burly buddies, and you'll still have the straps. Heavy duty straps mind, not cheapo luggage straps.

    Chris
     
  9. Mr48chev
    Joined: Dec 28, 2007
    Posts: 31,010

    Mr48chev
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    I've had this axle and spring in my stash for the past 40 years. My buddy got it with a T bucket project and traded it to me for an 8 inch Ford Rear.
    Since one has to use a spreader to hook the Ford cross leaf to the shackles in the first place I figure that the weight of the car will push down enough to spread the ends of the spring out enough but not too much.

    [​IMG]
     
  10. Pete Eastwood
    Joined: Jul 27, 2011
    Posts: 1,126

    Pete Eastwood
    Member
    from california

    Model T rear spring hangers are 48 inches , center to center .
    Hope this helps
     
    warbird1 likes this.
  11. Doublepumper
    Joined: Jun 26, 2016
    Posts: 1,154

    Doublepumper
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    from WA-OR, USA

  12. Pete1
    Joined: Aug 23, 2004
    Posts: 2,081

    Pete1
    Member
    from Wa.

    It will work fine as is. The car will handle better than if the shackles were hanging a bit. Been there, done it many times.
    If you grind those old spring pads off, which puts quite a bit of heat into the housing not to mention the stress relief on the old welds, you might end up having to straighten the housings.
     
  13. Mr48chev
    Joined: Dec 28, 2007
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    Looking at I don't think there is a real problem. the spring should spread out and settle right down so the shackles are at a 45 degree angle or close to it.
    T spring red axle (2).jpeg
     
  14. 37gas
    Joined: May 25, 2013
    Posts: 107

    37gas
    Member

    1/4 in spacer between axle and adapter. With weight on rear of car you should be good. If not add a thicker spacer and longer bolts
     
    choffman41 likes this.
  15. nonipshere
    Joined: Feb 20, 2012
    Posts: 146

    nonipshere
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    OK thanks. I'll take a look.
     
  16. nonipshere
    Joined: Feb 20, 2012
    Posts: 146

    nonipshere
    Member

    Ok. My main concern is how well or poor would they work. as far as the spring pads, I don't intend to remove them. Thanks for input.
     
  17. nonipshere
    Joined: Feb 20, 2012
    Posts: 146

    nonipshere
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    Thanks. I was thinking of that.
     
  18. nonipshere
    Joined: Feb 20, 2012
    Posts: 146

    nonipshere
    Member

    thanks
     
  19. nonipshere
    Joined: Feb 20, 2012
    Posts: 146

    nonipshere
    Member

    thanks
     
  20. nonipshere
    Joined: Feb 20, 2012
    Posts: 146

    nonipshere
    Member

    thanks
     
  21. Mr48chev
    Joined: Dec 28, 2007
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    Outside of showing everyone you were too lazy to spend 30 minutes cutting them off and cleaning it up smooth the real issue may be that with the leaves removed the spring might hit the pads but time will tell on that one.
     
    gimpyshotrods and X38 like this.
  22. gary macdonald
    Joined: Jan 18, 2021
    Posts: 208

    gary macdonald
    Member

    The weight of the car should bring everything into the correct alignment. The spring however has a issue I would resolve. It seems you’ve remove the 3rd leaf ? If so I see a weak point in your design that could snap or bend the 2 leafs that are worked the most .
    I too suggest removing the previous used pads , not a big deal but it does clean up the look of a banjo rear with the long tapered axle housing . Just aesthetics.
     
  23. nonipshere
    Joined: Feb 20, 2012
    Posts: 146

    nonipshere
    Member

    Too Lazy? If it becomes an issue I'll do it. The spring is extensively stretched horizontally. At this point, I don't see it reaching the pads regardless of the additional weight placed on it. It's a roadster body. Advice is welcome. Useless criticism isn't.
     
  24. Since you are calling him lazy let’s see pictures of what you are currently building?

    For the op, keep going man it’s looking good.
     
    HotRod33 and TA DAD like this.
  25. trollst
    Joined: Jan 27, 2012
    Posts: 2,090

    trollst
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    There's nothing wrong with your setup, there's no weight on the chassis, nothing to make the spring settle. The spring is fine, built, the car may weigh 2000 lbs, you won't break a leaf. Get on with it, stop overthinking the damned thing, it's fine.
     
  26. Test it... put about 250-300 pounds of sand bags on the back of the frame to see what it does. That will give you your answer.
     
  27. nonipshere
    Joined: Feb 20, 2012
    Posts: 146

    nonipshere
    Member

    Thanks.
     
  28. nonipshere
    Joined: Feb 20, 2012
    Posts: 146

    nonipshere
    Member

    Thanks
     
  29. HotRod33
    Joined: Oct 5, 2008
    Posts: 2,537

    HotRod33
    Member

    So who pissed in your Cheerios??? He asked a question??? So it's not up to your standards .... to bad...
     
    Last edited: Jul 3, 2021
    57 Fargo likes this.
  30. nonipshere
    Joined: Feb 20, 2012
    Posts: 146

    nonipshere
    Member

    Agree.
     
    HotRod33 likes this.

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