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Projects Soft axle? What's going on here?

Discussion in 'The Hokey Ass Message Board' started by 31Vicky with a hemi, Jun 15, 2016.

  1. First I'll say that I can not detect any movement in the kingpins or the wheel bearings.

    Somebody please check me here before I go off.

    This is a super bell axle, customer purchased a front end kit from honest Charley back in October 2014. I remember there were some bad ones out but can't remember the time frame.

    I'll give some static pics first, so you can get your bearings.
    Then I'll post some dynamics and the movement I'm seeing.
    Drove it for the first time yesterday. Brought it back in for caster tweak and some death wobble then started finding this crap.



    Ok so first thing noticed is a huge camber change when it gets some weight on or off the axle.

    Setting on the ground full weight. Watch the tire's center mold line.

    Next with the jack in the center of axle


    With jack under drivers wishbone mount
    Here's 2 jacks - 1 under each spring mount.

    Next problem I'm seeing.
    The drivers side of the axle seems to be rotating around the spring perch.
    Check the zip tie on the shock.
    First pic is just putting tension to turn right. Which pulls back on steering arm.

    Next is tension to turn left, pushes on steering arm.
    image.jpeg ,the variation you're seeing is the distance the lower shock mount is moving up and down while the axle twists. No movement that I can feel, see or measure in the radius rods

    Here's the movement at the king pin. Tape was attached to the frame further back.
    Tension to right turn first- then tension to left turn.
    3/8" +/-

  2. Wow that is some serious variance. Never seen anything move that much. Crazy....
  3. From what I understand you just step on a forged axle on the shop floor and flex it a half an inch.:rolleyes:

    I hate to say it my friend but I may be w little concerned about the axle. I do recall Super Bell having some problems a couple of years back but I can't give you a time period for sure. Unfortunately no one in our industry has anyway of tracking batch numbers. If I was getting death wobble I may suspect that this may be the cause of it.
  4. oj
    Joined: Jul 27, 2008
    Posts: 6,247


    I've seen Model A axles do that if you are just sitting and turn the wheels, the axle will noticebly move. I've never seen one move if the front is on a jackstand and tires off the ground. A superbell I worked on last week didn't move with tires on the ground. It had panhard bar and stabilizer and drove like a new car.
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  5. Well we shall see soon
  6. alchemy
    Joined: Sep 27, 2002
    Posts: 15,191


    My brother's fenderless A pickup had a stretched and hammered dropped 34 I beam that you could see it move when he drove over bumps and turned the wheel. He was nervous so he replaced it with a regularly dropped (heated, not hammered) 34 axle. I doubt his axle bent much when he had a jack under the center though.
  7. The37Kid
    Joined: Apr 30, 2004
    Posts: 26,736


    Do things move more or less with a reversed eye spring? Bob
  8. squirrel
    Joined: Sep 23, 2004
    Posts: 45,352


    that raised steering arm is applying a lot of torque to the axle when you steer.

    But generally we refer to a metal as "soft" if it has a low yield strength. We don't expect a steel (or iron) part to have a different modulus of elasticity than normal (30x10^6), which is what you seem to be implying it has.
    Andy, zuke, redlineracer42 and 4 others like this.
  9. What's the Modulus of elasticity of double bubble ? image.jpeg
    Last edited: Jun 15, 2016
    Just Gary, Duellym and belair like this.
  10. tfeverfred
    Joined: Nov 11, 2006
    Posts: 15,796


    Have it magnafluxed.
  11. Won't that only tell him if it's cracked? And from what he is describing I don't think that's it
  12. Well I followed "this guys" lead on the steering arm.
    This axle isn't dropped though.




    So if the torque from the raised steering arm is causing 1/2 of the troubles it's good to know the Arm I made is stronger than the axle


    I don't want to see or find this, and that's about where all the bending is coming from. BOTH The camber bend when loaded /unloaded and the caster twisting seem to be happening right there.
  13. tfeverfred
    Joined: Nov 11, 2006
    Posts: 15,796


    Then wouldn't the idea be to eliminate a crack from the equation? Just solving an equation using the scientific method.
  14. Torana68
    Joined: Jan 28, 2008
    Posts: 1,138

    from Australia

    little confused, the axle moving up/down when turning, was that with weight on or jacked up, if just sitting there it should , but equally both sides, try it in you new ot car , you will see the front go up/down from lock to lock.
    If that's a cast axle Id chuck it............
    the Modulus of elasticity of double bubble is probably around .05?((109 N/m2, GPa) opinions?
    Squablow likes this.
  15. belair
    Joined: Jul 10, 2006
    Posts: 8,330


    Yeah-I NEVER expect steel or iron to have a different modulus of elasticity than normal (30x10^6).
    Chucky likes this.
  16. squirrel
    Joined: Sep 23, 2004
    Posts: 45,352


    Find the Spencer car, wiggle the steering wheel back and forth, see how much the axle moves around.

  17. Hnstray
    Joined: Aug 23, 2009
    Posts: 11,269

    from Quincy, IL

    The caster angle and king pin inclination of the king pins will cause the spindle to rise or lower when the wheels are turned...the left wheel will rise when turned left, lower when turned right......opposite vertical movements for right side wheel.

    That doesn't account for the other aberrations noted though.

    edit: axle seems 'springy' more than 'soft'. Soft would yield and take a new set.

    Last edited: Jun 19, 2016
  18. It would - but I would have to think with how much movement he is experiencing he would be able to see the crack as it opened and closed to make that much difference.
    31Vicky with a hemi likes this.
  19. metlmunchr
    Joined: Jan 16, 2010
    Posts: 730


    Super Bell axles are cast from ductile iron. The elastic modulus for DI in beam loading is about 20.5 x 10^6 so, for equal sections and loading,. the DI axle would deflect about 1.5 times as much as a steel axle. This assumes high quality ductile iron. If the actual material happens to be closer to grey iron then the modulus can drop to 15 or less and the deflection can be twice or more of the deflection for steel.
  20. chris' 38
    Joined: Oct 24, 2010
    Posts: 307

    chris' 38

    I think I can translate that. Your axle is shit.
  21. BamaMav
    Joined: Jun 19, 2011
    Posts: 3,996

    from Berry, AL

    I agree, normal for one side to rise when turning. The other monkey motions though point to a flaw in the axle or it's design somehow.
    D-Russ likes this.
  22. Run a string or straight edge from left to right so it touches the mid portion of the axle then measure the distance from it to any point at each end of the axle. Do this twice. Once with wheel on the ground then again with wheels off the ground.
  23. Atwater Mike
    Joined: May 31, 2002
    Posts: 9,954

    Atwater Mike

    First post was correct: 'soft' material.
    "Is this Super Bell cast or forged?" / "Is this prostitute virgin or 'worldly'?"
    Even the ends of the Super Bell tubes were cast! (ductile)
    No forged Super Bells. (the axles that were breaking were some from another firm, with a similar name. (Super=Mag---) But made from the same shLt.)

    The upward steering arm on Doane's roadster was like that because of the high location of the steering box and pitman arm. Doane 'leveled' his drag link, but the stock axle was not akin to 'roll', as the spindle centerline was close to the axle's.
    The deep drop in the Super Bell is aggravated by the mean leverage put upon it by the added height of the steering arm.
    "I can bend that axle in 3 notes, Dick..." ...And I can.
    redlineracer42 likes this.
  24. On my 32 3 window I had an original 32 axle that was dropped by Ed Stewart some 50 years ago. It would flex all over the place when turning if you dared to watch it - But it NEVER induced Death Wobble!
    57tailgater likes this.
  25. Just be extra clear here about the amount of turning done for the pictures--

    The spindles rotation about the king pin is somewhere between 0 and 1* - nominally "none".

    the axle isn't going up and down, it's twisting and the lower shock mount is the pointer.
  26. i think the axle should be changed. even if "they" are supposed to flex like would bother me and i am guessing it will always bother you.
    i like the original stuff.
    tfeverfred likes this.
  27. I yanked the front end out of Elvis and swapped it into the Willys pictured here. I'll Swap the steering arm and see if I get the same results. That's a dropped super bell too but much made much earlier.

    It's got me flustered, not warm and Fuzzy.
    I have an older dropped CE axle I might put in it just to see. That one is supposed to be forged.
    Atwater Mike likes this.
  28. if it came out of that car it explains a lot.:D check it with a magnet.:rolleyes:;)
    kidcampbell71 likes this.
  29. tfeverfred
    Joined: Nov 11, 2006
    Posts: 15,796


    In a situation where physical laws seemed to be askew, the only course of action is to systematically eliminate the variables. Thus, I'd test for a hairline crack.

    First off, the OP's use of the word "soft" is incorrect for an axle made of metals or even metal compounds. Soft metals are:
    • ithium.
    • sodium.
    • potassium.
    • rubidium.
    • caesium.
    • francium
    to name a few.

    If his axle was forged, we'd suspect it's somehow bending, but that would be under severe conditions. He suggest it hasn't been subjected to those conditions. Therefore, I'd think a hairline crack on it's way to breaking, MAY be the problem. Superbells are cast.
  30. Lmao!

    No no no no.
    The one pictured here in this thread came new out of a box.
    The chrome one from Elvis came from a Hamb member, older but never on the road.
    tb33anda3rd likes this.

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