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D60 "Death Wobble"?.....here's a simple test for you.

Discussion in 'The Garage' started by Greg72, Apr 1, 2003.

  1. Greg72

    Greg72 "Might As Well..." Staff Member Super Moderator

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    D60 \"Death Wobble\"?.....here\'s a simple test for you.

    I know that the topic of DW has been beaten to death on other threads, but one of the things that has always seemed curious is that there was not a clear correlation between the setups people had, and the existence of DW....or lack of DW. I know that one prevailing theory (assuming all the front end parts are new) is that the amount of caster can make a difference. I'd always wanted to measure this on mine to see if it was within "spec"....but assumed I'd need to go to an alignment shop to have them take the measurement.

    During a discussion with Stephen Watson today, he suggested something SO simple.....that I couldn't resist sharing it. IF you are using his crossover steering setup, then the passenger-side steering arm is EXACTLY perpendicular to the steering axis. All you have to do is park on a level surface, and lay an angle finder on that steering arm....and Voila!....you can measure your caster!!!

    I think it would be a GREAT idea for folks to post up their measurements from this technique, as well as a comment about whether they have/had DW or not. Also, since a stabilizer (hydro-assist) tends to "mask" DW, you might want to mention if you have those too.

    So here's mine:

    11 degrees of positive caster (TOO MUCH of a good thing!). I have a stock, worn out stabilizer and have noticed DW tendencies with my 38's, but never a "full-on" episode. With skinnier tires mounted I have DEFINITELY experienced it though! /forums/images/graemlins/eek.gif

    Looks like I need to shim-up the pinion to get closer to a 4* - 8* number....???




    OK folks, post 'em up! /forums/images/graemlins/thumb.gif
     
  2. 4X4HIGH

    4X4HIGH 1 ton status Premium Member GMOTM Winner

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    Re: D60 \"Death Wobble\"?.....here\'s a simple test for you.

    OK Greg, I am going to post here so that everyone else might want to check their caster angle after what I discovered to possibly be the fix for DW. Like I told you before I installed my D60 I figured that the cause is most likely too much or too little caster angle. I looked up the specs for a 1 ton truck and it is supposed to be 4* unlike a 1/2 ton that likes 5*-8*. Anyway, I checked my caster angle tonight and found out that it is at 4* and as you know Greg, I don't have any DW and that is without a steering stabilizer of any kind as you know. So people, I think my theory of too much or too little caster angle is the cure for DW.
     
  3. 70~K5

    70~K5 1/2 ton status

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    Re: D60 \"Death Wobble\"?.....here\'s a simple test for you.

    [ QUOTE ]
    OK Greg, I am going to post here so that everyone else might want to check their caster angle after what I discovered to possibly be the fix for DW. Like I told you before I installed my D60 I figured that the cause is most likely too much or too little caster angle. I looked up the specs for a 1 ton truck and it is supposed to be 4* unlike a 1/2 ton that likes 5*-8*. Anyway, I checked my caster angle tonight and found out that it is at 4* and as you know Greg, I don't have any DW and that is without a steering stabilizer of any kind as you know. So people, I think my theory of too much or too little caster angle is the cure for DW.

    [/ QUOTE ]

    Scott, I'm sure caster angle has something to do with it, but you also rebuilt the kingpins etc on your axle.
     
  4. 4GUNZ4X4Z

    4GUNZ4X4Z 1/2 ton status

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    Re: D60 \"Death Wobble\"?.....here\'s a simple test for you.

    [ QUOTE ]
    but you also rebuilt the kingpins etc on your axle.

    [/ QUOTE ]

    I put on a brand spank'n new d60 on my K5 and experienced DW within the first 20miles. Nothing rebuilt, nothing worn, only thing changed from factory to my house was gear and locker with 0 miles on complete axle.

    I know my caster is off but by how much I dont know. I'll post back when I get measurements and results of/after adjustment.
     
  5. txbartman

    txbartman 1/2 ton status

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    Re: D60 \"Death Wobble\"?.....here\'s a simple test for you.

    My D60 has/had serious DW. Around 20MPH, the front fenders darn near come flying off. The caster on mine is definitely out of whack, although I haven't officially measured it yet. I installed a WTO Redneck Ram and it masks it, but I can still feel it under the ram (so to speak) and don't like it as a permanent solution. I am sure it cannot be good for the ram to be pulsating like that.

    Anyway, I will measure mine this weekend. Big problem I have is that I also run zero rates (offsets) and high steer. I can't put much shim or the tie rod may start to impact the springs. I am going to have to find a happy medium somehow.
     
  6. Greg72

    Greg72 "Might As Well..." Staff Member Super Moderator

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    Re: D60 \"Death Wobble\"?.....here\'s a simple test for you.

    Bruce,

    True.....but my D60 is completely rebuilt. In fact Scott helped me with my rebuild it also!!! The fact that two D60's can be rebuilt (by the same person), and one can have DW and the other one doesn't.....really makes you wonder if the problem is with the "orientation" of that axle under the truck (caster)

    Anyway, I'll be interested to see a few more data points and caster values on this thread! /forums/images/graemlins/cool.gif
     
  7. Sandman

    Sandman 3/4 ton status Author

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    Re: D60 \"Death Wobble\"?.....here\'s a simple test for you.

    Wow. I run 40" boggers with crossover and no stabalizer right now and I have no Wobble at any speed. It does wander some but maybe a stock stabalizer might help that.

    I did do the washer trick though.
     
  8. Greg72

    Greg72 "Might As Well..." Staff Member Super Moderator

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    Re: D60 \"Death Wobble\"?.....here\'s a simple test for you.

    Sandman,


    .......AND....... what's your caster meaurement? /forums/images/graemlins/smile.gif
     
  9. txbartman

    txbartman 1/2 ton status

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    Re: D60 \"Death Wobble\"?.....here\'s a simple test for you.

    I guess I should qualify my setup...

    Military D60
    42" TSLs
    WTO Redneck Ram - no stabilizer
    Hi/Crossover Steering (Parts Mike setup)
    washer trick applied

    Without the ram it is undriveable.
     
  10. Sandman

    Sandman 3/4 ton status Author

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    Re: D60 \"Death Wobble\"?.....here\'s a simple test for you.

    I'll have to measure it. What I have is the TC 6" springs with the axle forward 1.5" and the ORD greaseable shackels.

    I used to run 6" Superlift springs with stock axels and the axle in the stock location, with regular steering and dual stabalizers and no washers. Still no death wobble but it did wander around a lot. The washers fixed that one.
     
  11. Greg72

    Greg72 "Might As Well..." Staff Member Super Moderator

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    Re: D60 \"Death Wobble\"?.....here\'s a simple test for you.

    That's part of the reason my caster is so high.....my front springs were built to move the axle forward 1". That has a side-effect of rotating the pinion DOWN and increasing caster.

    I'll be curious to hear what your measurement is....since your axle is even MORE forward than mine!
     
  12. Sandman

    Sandman 3/4 ton status Author

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    Re: D60 \"Death Wobble\"?.....here\'s a simple test for you.

    I'll try to get it measured this afternoon. /forums/images/graemlins/thumb.gif
     
  13. Waxer

    Waxer 1/2 ton status Author

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    Re: D60 \"Death Wobble\"?.....here\'s a simple test for you.

    I gotta buy an angle finder at HF, and then I will measure mine. Most likely this weekend.
     
  14. FWP

    FWP CRS

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    Re: D60 \"Death Wobble\"?.....here\'s a simple test for you.

    Interesting Greg....

    I have 9*, no DW if the steering stabilizer is in place and working. A month or so back, after wheeling, the stabilizer was shot, and I got DW. Replaced it and it was gone. After that, I added shims to the caps to preload the king pin springs. That's where things are at now.
     
  15. Don

    Don 1/2 ton status

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    Re: D60 \"Death Wobble\"?.....here\'s a simple test for you.

    Great Topic! I have one under mine, it's out of a 78 K30. Although it's been in for almost 2 year's now, the first time I drove it, and drove over a manhole cover,WOW! Slam, Shake, Shimmy, Shimmy,Whack! I thought the whole damn Axle was coming out from under the truck!

    I have'nt measured castor, everything was replaced before It was installed. I ran out and bought a Steering stabilizer, which helped considerably, but it still occassionally "wiggle's. /forums/images/graemlins/eek.gif
     
  16. 4GUNZ4X4Z

    4GUNZ4X4Z 1/2 ton status

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    Re: D60 \"Death Wobble\"?.....here\'s a simple test for you.

    What I miss? The washer trick? Whats that?
     
  17. 4X4HIGH

    4X4HIGH 1 ton status Premium Member GMOTM Winner

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    Re: D60 \"Death Wobble\"?.....here\'s a simple test for you.

    People have been installing a 1/4" thick spacer or stack of washers under the spring cap to give the spring more tension. IMHO this is only a bandaid to a serious problem, in fact I believe that all that will do is nothing more than prematurely wear out the upper king pin bushings.
     
  18. Toledo

    Toledo 1/2 ton status

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    Re: D60 \"Death Wobble\"?.....here\'s a simple test for you.

    Did anybody ever have any measurements to add to this?
     
  19. Don

    Don 1/2 ton status

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    Re: D60 \"Death Wobble\"?.....here\'s a simple test for you.

    I'll check mine tomorrow and let You know, hell I'm as interested as You are. Mine is at 4" lift with little skinny MTR"s on it, it did wobble to beat hell though, until I added a Stabilizer to it. /forums/images/graemlins/eek.gif
     
  20. DaveCowley

    DaveCowley 1/2 ton status

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    Re: D60 \"Death Wobble\"?.....here\'s a simple test for you.

    My 88 has a D60 under it. 5* of castor, and it had the DW but I did the washer trick as well and it doesn't wobble anymore.
     

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