97 f350 diesel 4wd crew - shakes when pothole hit

You may have some worn linkages but the root of your problem is the front end alignment itself. It is unstable and it depends on being held stable. This is also sometimes called the "Caster Death Wooble". It can get really violent at times and feel like front end is going to shake itself to pieces. Many try to control this with tight linkages and stabilers but the real long term cure is proper alignment. When you get the right combo of caster and toe in the front end get unstable and when given a chance to shake it can go crazy. It stops when you slow down because the road force excerted on axle via toe in and camber decrease with speed and stabilty returns for a while.

----------------- TheSnoMan.com

is a link to a nice write up about the 'death wobble'not that you, Ken, don't already know what it is i had a buddy pick me up to go fishing in his 80ish

4x4 pick-up, about a half mile from my place at about 45 he hit a pot hole and the truck went into the 'dw' he got it under control but I made him stop and i walked home

yes, and 99 times out of a hundred it's either a dually type wheel or oversized out of balance tires that cause it. (in addition to the worn parts)

OK, THANKS ALL !

I'll give that a try, hasn't been aligned in a while and needs it now that I changed all the steering and linkages.

Had this same problem on an older Ford truck. Problem solved when steering box gears were CENTERED WW>

On Sat, 05 May 2007 14:50:06 -0700, tracy rearranged some electrons to form:

You changed front end parts and didn't have it aligned? No wonder. File that under "duh".

Pay close attention to caster angle and toe in because when these are wrong for your vehicles setup it can cause the "death wobble" Sometimes stock setting do not work with some configurations.

----------------- TheSnoMan.com

Thanks David, you reply shows you are indeed an ass.

In any case, thanks to the rest of you, you're suggestions regarding too much toe causing my DEATH WOBBLE iwere right on.

As for not having the truck aligned following parts change, parts were changed to fix the wobble, and the outer tie rods were completely worn out, since the tires were not moved and all parts were reinstalled to same lengths as old ones, did not necessarily mean it needed an alignment, DAVID.

The fact is the front leaf spring shackles have play in the top of the bracket and allow the differential to torque back and forth slightly, I used a laser and shot a beam against a t square laid up against the sidewall of the tire and projected it 25 feet in front of the truck

The width at the truck was 6 feet 6 inches, the width 25 feet in front of the truck was 4 feet 6 inches, so yes, the truck had significant toe in BEFORE and after the parts change. Turned the adjuster 5 turns and got the laser to spread and now I am real close to 0 degree toe in. Beam at 25 feet is 6 feet 6 inches but there is room for error there, so could be positive negative slight toe in out.

Proof is in the test drive, took it out, hit the test pot hole at 55, and I could feel the truck THINK SLIGHTLY about doing something but it never did. Didn't even shake the wheel, but I can feel it the shackles hitting their sloppy ends. Thats what I was feeling in the steering when I drive 3 miles an hour on rough 4 inch gravel and thought it was the steering box.

So I am going to try and look at the shackle bracket where it mounts to the frame to see what needs to be done to get rid of the slop there, then I should be good to go.

But the good news is I can drive the truck again, no way I could have driven it before.

THANKS GUYS (except David, nobody likes a smart ass with nothing to contribute but negativity and personal comments, go get a life).

You know, the reason some of us come to forums like this is we can't afford to raise a family AND pay outrageous repair bills, so far I have been quoted 4500 to fix this problem, instead, I replaced all the tie rods and steering box for 900 and my time. And I aint no mechanic. So think about that next time before you decide to inform someone about what a DUH they are being. I think I did a hell of a job. And saved may family 3600 to boot.

THANKS AGAIN ALL, YOU ROCK!!! .

"> Thanks David, you reply shows you are indeed an ass.

To the OP. I agree the amounts quoted to you were exorbitant. Just for the record, David wasn't being an ass. He was telling you the truth, and it was something you should have known, just as important as oil changes. Vehicle alignment is one of the most neglected maintenance items on a vehicle, and lack of it was possibly the cause of the extreme wear on yours. You always have a vehicle aligned after replacing front end parts, and as a rule, get the front end checked a couple of times a year, at least once, and after any major front end bump up or incident occurs. It costs less than $100.00, and in most cases less than $50.00. Alignment checks tell you if you have problems in the front end and suspension, and if they are potentially dangerous, or costly, and give you advance warning or time to stop something before it gets that way. Granted there are lots of opportunities for you to be taken advantage of as well, so find a place you trust and go with them. Have your wheels checked for balance as well when you do this. That preventative maintenance will save you lots in the long run, then you can have money to "take care of your family", as you said You said you addressed the toe, but what did you do about caster and camber?

Spdloader

On Tue, 08 May 2007 19:01:58 -0700, tracy rearranged some electrons to form:

Thanks Tracy, your reply shows you are indeed ignorant.

You just confirmed what I said. You replaced parts, and the alignment was not right.

Anytime you change worn parts, you affect the alignment. No matter how close you try to get the length of the tie rods, it won't be the same.

As you so elegantly proved.

I guess you learned something then...

1) A plumb bob and a level aren't the same as an alignment machine. 2) A front end alignment costs a lot less than shotgunning replacement parts (like a steering gear).

Glad I could be of service.

With the wobble happening only after an impact I would have thought loose front end parts. The front end alignment normally effects handling and tyre wear. The wobble is a symptom that is accentuated as the woen parts have more play. I would have looked at linkage ball joints or king pins. King pins on a larger truck are a pain. Oh. An alignment will pick up on all that stuff. Alex

Doesn't an F350 have a beam axle, i.e. caster and camber aren't adjustable (or at least not easily)

nate

Camber and caster are adjusted with eccentric ball joint sleeves. Spdloader

I'm inclined to agree that the front end alignment played a role in this, as I experienced the same thing with my 78 Bronco after replacing a worn tie rod end in my driveway. I figured that I had the toe-in set up pretty close to spec (wrong!), and then I took it out for a test run that I'll never forget. Everything seemed OK until I reached 45 mph or so, when the front end suddenly went violently crazy for ten seconds or so. I finally regained control of the truck when the speed dropped to around 10 mph on the gravel shoulder on the opposite side of the road, so I'm glad nobody else was around at the time or it would have been a really bad day.

So they call that a "Death Wobble" eh? That's a good name for it.

Cheers, Ken