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Bouncey straight axle front end...

Discussion in 'The Hokey Ass Message Board' started by awsomeears, Jan 14, 2014.

  1. awsomeears
    Joined: Feb 5, 2011
    Posts: 159

    awsomeears
    Member

    Last year I received some incredible information from you guys, just by pictures you were pointing out what is going wrong, long story short I took it to a fab shop and in a few days Ron fixed all of it.

    Here was the original link http://www.jalopyjournal.com/forum/showthread.php?t=720800

    Now I'm 100% happy with his work, but now I'm asking for some more incite from the straight axle guys. It could be possible I'm expecting a Cadillac ride :p

    While driving my front end will get into a bouncing mode, similar to a pogo stick, up and down up and down. The car is not hard to handle left or right or power steers just the up and down motion.

    I started to think, could it be my leaf springs are to stiff and not letting my shocks actually dampen and slow the bounce down, I ended up placing ZIP TIES on my shocks and drove around for a bit and found the compression is about 3/4" of an inch travel.

    Its winter here in Wisconsin and before I stored the car I really should have removed the shocks and see how it handled, to prove if the shocks did anything at all for rebound.

    The shocks appear to be speedway shorty's...

    Any thoughts would be great, if more info or pictures are needed please let me know

    - Brad -

    * UPDATE * 1/15/14

    Here are the pictures I should have posted right away :rolleyes:

    The leaf width is 1 5/8 and the leaf spring length eye to eye is 26 1/2 in length. The Front Leaf Spring Axle Pad and U-bolts are new and bought from speedway.

    [​IMG]

    [​IMG] You can see the zip tie, that is the Total Travel from a drive around town

    [​IMG]

    [​IMG]

    [​IMG]
     
    Last edited: Jan 15, 2014
  2. BJR
    Joined: Mar 11, 2005
    Posts: 6,086

    BJR
    Member

    Too stiff a spring will make a car bouncy. Look at an unloaded trailer, it bounces at every little bump. That's because with nothing in it the springs are too stiff. Put a load in it and the trailer ride smoothes right out. Since you cannot put more weight on the spring, you need to remove leaves or get spring with less weight caring capacity.
     
  3. squirrel
    Joined: Sep 23, 2004
    Posts: 44,635

    squirrel
    Member

    How about some pictures of how the suspension looks now? like the shock, spring, shackles, etc. Might need to remove a wheel to get a good look at it for us. And several pics from different angles, side view, 45 degrees, front view, etc.
     
  4. gimpyshotrods
    Joined: May 20, 2009
    Posts: 16,581

    gimpyshotrods
    Member

    Leaf springs are too stiff, shocks have insufficient dampening capability, or both.
     
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  5. awsomeears
    Joined: Feb 5, 2011
    Posts: 159

    awsomeears
    Member

    I should have really taken pictures and then posted this :cool: I will snap some pictures tomorrow.

    In my 1st post of the old thread the leaf springs are the same, but I don't want to post that picture to get everyone confused. The same shocks were used but now are welded up and down and not on that radical angle.

    The leaf springs have 3 separate springs total, tomorrow I will get measurements as well

    Thanks...
     
    Last edited: Jan 14, 2014
  6. Check your tires for any issues and roundness.
     
  7. Don's Hot Rods
    Joined: Oct 7, 2005
    Posts: 8,319

    Don's Hot Rods
    Member
    from florida

    Without pictures we are flying blind. Post up lots of them from different angles so we can get a good idea what you have there.

    Don
     
  8. gimpyshotrods
    Joined: May 20, 2009
    Posts: 16,581

    gimpyshotrods
    Member

    There are a bunch of pictures in his original thread. Just the shocks have been moved.
     
  9. Don's Hot Rods
    Joined: Oct 7, 2005
    Posts: 8,319

    Don's Hot Rods
    Member
    from florida

    The one thing I see that might be a problem is the shortness of those springs. Longer springs allow the front end to ride better. Glad you changed the angle of those shocks, they were really not doing a thing the way they were.

    Don

    [​IMG]
     
  10. doinbad
    Joined: Sep 17, 2012
    Posts: 322

    doinbad
    Member
    from celina tn

    Those look like trailer springs! i bought a model a took spring off cause it looked to short,they didnt even take trailer spring sticker off the top!
     

    Attached Files:

    Last edited: Jan 15, 2014
  11. SBCWelder
    Joined: Jun 24, 2013
    Posts: 51

    SBCWelder
    Member

    I'm certainly no chassis expert, but the upper eyelet of the shock being turned that way may be causing a binding issue as well with the shock at that much of an angle
     
  12. James Curl
    Joined: Mar 28, 2006
    Posts: 370

    James Curl
    Member

    If your shackles are too short they cannot allow enough travel for the increased length of the spring as it is compressed. Once the shackle is parallel to the centerline between the solid frame attachment point and the shackle attaching bushing the spring is stopped from any upward travel by the distance between attaching points that is shorter than the spring is when placed under load and the arch reduced.
     
  13. squirrel
    Joined: Sep 23, 2004
    Posts: 44,635

    squirrel
    Member

    That's what my guess is....springs have way too much rate, because they are too short, and the leaves are too thick.

    The springs I put on mine run the entire length of the front subframe....
     
  14. Blue One
    Joined: Feb 6, 2010
    Posts: 10,147

    Blue One
    ALLIANCE MEMBER
    from Alberta

    If you bothered to read anything before you posted, you would have seen that the shocks have been changed to a different angle and are now straight up :rolleyes:
     
  15. Judd
    Joined: Feb 26, 2003
    Posts: 1,894

    Judd
    Member

    My Comet had this problem and I cured it by removing one leaf on each side.
     
  16. 1971BB427
    Joined: Mar 6, 2010
    Posts: 5,538

    1971BB427
    Member
    from Oregon

    Too much spring, and the trailer springs will be tougher to adjust with the thick minimal number of springs used. I'd take the longest spring after the main out. If that doesn't do it, then take another.
     
  17. Rework your shock mount,,it can't possibly be doing the job,,it needs to be straight up with the short springs.

    Something similar to this. HRP

    [​IMG]
     
  18. One thing to consider and is going to make me very unpopular is that you are using speedway shocks of questionable quality. Try a name brand shock like a Monroe or ???, a gas shock or notrogen cell shock is a good idea. hell just to make me more unpopular when I was driving mud trucks I liked Ranchos. :eek:

    There is always the possibility that your springs are too stiff, that is common across the board here. Everything from A coupes to surf vans have too much spring. No way to know that without knowing the rping rate and the front end weight, but you could try removing a leaf andf seeing if you get any change, if so work with the local spring shop to build the proper rate spring for your car.
     
  19. http://www.jalopyjournal.com/forum/showthread.php?t=202296
    Here's some more spring rate calculator stuff.

    Just guessing that the spring is 1.75 x 0.38 x 26 x 3 leafs and that's about 1000lb spring each up front. Also that's about the smallest cheapest trailer springs available. About 20.00 each.
     
  20. gimpyshotrods
    Joined: May 20, 2009
    Posts: 16,581

    gimpyshotrods
    Member

    I'd like to see a spring with more, thinner leaves, about twice the overall length of this spring, with shackles about twice as long, too.

    And yeah, those appear to be springs designed for a 2000lb. trailer axle.

    And ol'Beaner is correct. Speedway shocks are mediocre, at best. Spend the money on good shocks.
     
  21. 34toddster
    Joined: Mar 28, 2006
    Posts: 1,470

    34toddster
    ALLIANCE MEMBER
    from Missouri

    What's up with the front shackle does it go forward when weight is applied?
     
  22. SBCWelder
    Joined: Jun 24, 2013
    Posts: 51

    SBCWelder
    Member

    Sorry, I didn't read 8 pages of a thread before posting. Saw the picture with the angled shocks and assumed it was the current setup.
    If that issue has been corrected, then that leaves spring rate and shackle angle which have both been addressed by other posters.

    Posted using the Full Custom H.A.M.B. App!
     
  23. DICK SPADARO
    Joined: Jun 6, 2005
    Posts: 1,887

    DICK SPADARO
    Member Emeritus

    Bouncey or just rough ride when you hit the expansion joints. I'm with other that think those are trailer springs, what is the load rate on those. Here is a quick backyard way to determine the spring size range you should be in--- Approximate front total load divided by 2 = spring load. So if the front end of your car weighs 1000 lbs/2 = 500 per wheel.. then / suspension travel- say 2" = 250lb spring
     
  24. Blue One
    Joined: Feb 6, 2010
    Posts: 10,147

    Blue One
    ALLIANCE MEMBER
    from Alberta

    That's ok, sometimes details are easy to miss. The shocks being changed is mentioned on post 5 of this thread, not buried 8 pages back. :)
     
  25. Very few actually read here!! It's comical almost.
    I guarantee I read 10-20 times the amount I post.
     
  26. Pete1
    Joined: Aug 23, 2004
    Posts: 1,693

    Pete1
    Member
    from Wa.

    If you decide to get rid of the cheap shocks, get some that are designed to mount BODY UP.
    Anything you can do to reduce unsprung weight helps.
     
  27. 2OLD2FAST
    Joined: Feb 3, 2010
    Posts: 2,009

    2OLD2FAST
    Member
    from illinois

    . Bounce on a straight axle can be induced by : out of round tires/ rims ,front OR rear ,bad shocks, wrong springs , toe-in/out, tire pressure, just to name a few .
    dave
     
  28. SBCWelder
    Joined: Jun 24, 2013
    Posts: 51

    SBCWelder
    Member

    Yep. Everything is spelled out clear as mud.
    I'm guilty of skimming over posts and picking out what I feel are the important bits. Obviously I missed an important detail this time around. I'll sit back and wait for the solution to be posted...

    Posted using the Full Custom H.A.M.B. App!
     
  29. tjet
    Joined: Mar 16, 2009
    Posts: 1,272

    tjet
    Member
    1. Early Hemi Tech

    Try adding some caster shims. Napa sells 3 degree & 6 degree shims. It sounds like it's progressive (it gets worse if unchecked - like a speed or load change).

    Sometimes all it takes to break a dynamic oscillation is to make a change in the force direction.
     

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