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Discussion Starter #1 (Edited)
Ok.....I've got a case of the wobbles.

Now, before I get started....let me say that this is a new onset. The rig was fine, then started wobbling.

Axle: 79 Ford F350 Dana 60. Stock, 4:10's with ARB. Superlift lockouts.

Rig: 95YJ on Tons. XJ springs front/rear.

The wobble: At roughly anything over 15 mph the front wheels will start shaking violently. I have to slow down to get it to stop. I can not drive "thru" it because the shaking is so bad. Few other small things. I noticed today that it feels like the drivers side more than the passenger. Maybe because I can actually see that one...but that's what it feels like. I also notice that while the wheels go back and forth, the steering wheel doesn't seem to move much. I'm on leafs with no trackbar, so the "play" of the rig may be absorbing some of that.


Ok, the rundown of things I've checked/looked at.

1. I tore down the entire front axle. All bearings/races/seals are in tact and no noticable wear.

2. Kingpins are in good shape, replaced the poly bushing on the kingpin.

3. New shackles, new poly shackle bushings/sleeves/greasable bolts.

4. Checked air pressure....all equal.

5. Tie rod ends are not sloppy.



Only thing I can see is maybe the tie rod has just a hair of arc, probably from rocks. It's not noticable until you stand back and specifically look for it.

While this sounds like classic "death wobble," it seems strange that this has never happened before on this axle. I've had the axle in there for about a year with no problems. I've wheeled it in moab/colorado/arkansas and drove to/from the trails at 60-70mph with no problems till recently.

My first thought is alignment. But I've had vehicles with horrible alignments that pull you off the road, but don't wobble. There is also no place locally that will can an alignment on 42" tires.


Any ideas?
 

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what is your front suspension setup? i had a bad wobble/axle wrap bc the track bar somehow got a huge amount of slop in it. it suddenly happened after a few thousand miles. just a guess. good luck
 

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Do your tires have any wear? Try rotating fron to back and see if it changes. If your tie rod is bent, your toe is in a bit further than it was and it could make a difference.
Travis..
 

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Mr. DJ
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do you have jamb nuts on your rod ends? if not and you have a collar that clamps around the tubing that could be your problem. my collars/clamps where loose enough that the rod ends would slip a tooth or ten. also check all steering bolts. tire pressure and balance. steering shock shot? start with a alignment. simple string will work. tie the string to your rear shock run string around rear tire pull it to the front and you can check your tow this way. you want your front tires to be towed in about a quarter inch or so.
 

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Discussion Starter #5 (Edited)
I swapped the drivers side tires front/back this morning....still wobbled up front, and no wobble/vibration on the back.

Couple things I noted this morning. I had forgotten that I removed the steering damper because it was leaking and shot. I'm wondering if it was just masking the wobble. Makes me rethink the caster ideas. I would imagine that on the stock F350, the spring pads were nearly horizontal. In my setup, because of mounting the front shackle hanger higher than stock mounting, that the angle of the springs has changed the caster....and the damper may have just covered it up. I've got a new damper ordered and will see if that corrects it. If so, I think I may order some shims to test the caster issue.
 

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Discussion Starter #6
The stabilizer corrected the wobble. Or in better terms, it reduced it to near nothing. If I look out the window and watch the tire, I can see where it ever so slightly starts at about 20mph. By 25mph it's gone.

In conclusion....I think I've always had the wobble, just kept it in check with the stabilizer....and hardly noticed it with 42" IROKs howling. When the stabilizer went south, wobble went north. Needless to say, I've got some shims ordered to see if that corrects the wobble. If they do, I'll redo the perches for a more permanent fix.

Note to self.....death wobble sucks.
 

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If the front of your spring is higher than normal, you should have a ton of positive caster. You need to check it before you start jacking with it. My opinion is that 4 or 5 degrees is plenty, some guys say up to 8 which sounds WAY to much to me.
Travis..
 

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Discussion Starter #8
If the front of your spring is higher than normal, you should have a ton of positive caster. You need to check it before you start jacking with it. My opinion is that 4 or 5 degrees is plenty, some guys say up to 8 which sounds WAY to much to me.
Travis..


I've got 6 degree shims ordered. We shall see.
 

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I've got 6 degree shims ordered. We shall see.

My buddy instead of buying the 6 deg shim. Ground down the cast in perch. Before he hit it with a grinding wheel he drilled the correct depth so that when he started grinding he knew not to go any lower than the different depth holes he drilled. You obviosly know your pinion angle is going to change. The shims just equal more leverage and the possibilty of messing up your springs.
 

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I've got 6 degree shims ordered. We shall see.
I was saying you most likely have alot of positive caster which is good, at least better than alot of negative:eek:. Figure what you have now, and get shims to make it what you want. Don't just throw parts at it blindly. I think your 6 degree shims are gonna put you too far the other way.
Travis..
 

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Discussion Starter #11
I was saying you most likely have alot of positive caster which is good, at least better than alot of negative:eek:. Figure what you have now, and get shims to make it what you want. Don't just throw parts at it blindly. I think your 6 degree shims are gonna put you too far the other way.
Travis..
I understand where your coming from. If it were 100 dollar parts....such as the new shackles/bushings/sleeves/bolts/kingpin bushings/steering stabilizer.......you get the point.

The shims are the cheap thing to try, they were 15 bucks. And I'm sure I can resell them after testing them. This really does come down to a caster issue. All the bearings are in good shape, there is no play in the wheels/bearings/kingpins/tierod ends. None. And 6 degree shims are really a minor adjustment in the scheme of it. Like I said.....we shall see. I'll post back on the thread after I test them with the results.
 

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i had a wobble problem on my 97 and i found out what was causing it after it failed and broke totally. the bracket that is welded onto the front axle where the stabilizer bar attaches to had actually been cracked for some time, and that weak link was enough to cause some serious wobble. it finally got so bad that it just broke all the way and i was easily able to see what the problem was. i thought that it was from a worn shock located on the stabilizer bar but after checking it out, it was fine but once the bracket broke completely off of the axle it was easy to know what was causing the wobble. i just cleaned it all up a bit with the grinder and welded it back in place and she rides wonderfully smooth now. sounds like your on the right track there.......good luck.
 
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