Death wobble alignment questions

So I have an alignment scheduled for tomorrow since I replaced the track bar and steering stabilizer and its still there, not as violent but noticeable. The truck does pull to the left and feels a bit sloppy hence the need for an alignment.

Now the guy on the phone said hes seen it and I quote. "99% of the time is the axle u-joint, not sure an alignment will help but we can start with that"

This is a very reputable shop in my area and seems like more and more 4x4s are heading to them. Now Im not quite so sure about that since in my old 1995 XJ I knew it had a bad u-joint, never had death wobble from that and it had a slight 2" lift on it.

My current XJ (2001) seems to be giving me problems ever since I bought it. Id hate to spend 1000s of dollars on this since a lift will be going on some time this summer.

Any advise???

Ballance tires, double and triple check the ball joints. Check the differential mount for the track bar. Pull shocks and see if they still work.
Start there.
Then, if all is well, toe out your tires 1/8" at a time to see if DW goes away. (this is only a temp fix)

Should have mentioned the tires will be re-balanced tomorrow as well.

Shocks are literally 2 weeks old.

Ball joints seem to be pretty tight doing the top and bottom of tire pushing/pulling method.

Differential mount...might need to check again

Lay under there, have someone else turn the wheel back and forth. Grab, touch, feel grope every moving component and watch for the slightest movement.
Change tires, front to back.
Wobble from speed, or braking, or hitting a small bump, or during a turn? 50-55 mph?

Everytime ive ever had DW was because the frame side Trackbar mount came loose after wheeling something like the rubicon for 3 days+. finally got the RE bar that goes across with the HD mount, and then finally welded the mount. no more trackbar related DW after a wheeling trip. I have gotten it before from some badly worn and badly unbalanced swampers in the past. balance fixed it right up. Oddly enough though, I currently run unbalanced iroks on beadlocked rims with no vibes or DW.

so tighten :
trackbar mount frame side
trackbar bolt axle side
all steering basically
check your caster, sometimes you can litterally eyeball it. that would explain the wandering and perhaps DW if you had too much negative caster. take a pic and post up.
check all control arm bushings
check axle shaft u joints(never had these cause DW though, only vibes, but they were totally toasted with some vibes, even then ,vibes were minimal)
check unit bearings
check ball joints
balance tires
make sure the steering box is tight.
i get at least one jeeper a week texting me about DW . 9 times out of 10 they say their trackbar is tight. 9 times out of 10 i show up with a breaker bar and crank on all of the trackbar bolts and help them realize that stuff was loose as hell, and often a hiem, or bushing in the TB is toasted as well. replace worn components and proper torque and you are good.



Ball joints and trackbars are cheap and easy to replace. same goes for the tie rod and drag link.



my money is on a bad trackbar or a loose bracket, or unevenly worn tires.

Pulling can mean a stuck caliper. calipers are cheap. could even be the issue. I read a thread on here a while back where dude found out it was the caliper causing the DW, I think.


also man, dont waste your time with a shop alignment. buy a tape measure. use the same vertical distance on the tires front and back for your measurements and get your front toe in dialed in. most 4x4 shops, if you call, will just tell you they charge you 75$ to basically bust out a tape measure,but they may or may not look for worn components.
after you have gone through all of the above, and do your toe yourself. as for caster, if you have adjustable UCAS, you can bring them in, if not, cut and weld your current ones shorter, if indeed , you have too much negative caster.

That is NOT how you adjust caster/pinion angle on a STOCK XJ or MJ.
The LCA mount on the frame side is the adjuster. Add/subtract shims to get pinion angle right (zero degrees) and forget caster unless it's causing drivability problems like wandering on a crowned road.

See FSM for details.

Is it lifted? It could help to know.

The pulling does sound like either alignment or stuck caliper. Check that the flat parts of the knuckle where the brake pad ears rest have grooves. Driveway alignment is good enough for eliminating any pull. I've never taken in any of my jeeps for alignments in years.

I used to have some shimmy/light wobble for a while and though it seems to be a combination of things the biggest difference was to replace all control arm bushings, uppers being surprisingly the biggest help. Replacing the axle-side UCA bushings seems daunting but is not that bad and was for me the single most effective fix.

I've since swapped the LP D30 to an HP D30 and had zero wobble issues since, despite a near-zero caster angle and 32" MT tires with BB beads in them.

HTH

My '96 had a funky pull, once in a while, but especially when braking. Turns out the slide surfaces on the knuckle where the pads ride had developed a divot, allowing a pad to wedge itself into the divot, causing the pad to drag. It literally wore the pad all the way down. I fixed it by filling in the void with weld, then buffing it down with a flapper wheel. The divot wasn't so much deep, but it had a sharp edge, like a step, and over time the ear on the pad couldn't slide back to its relaxed position. If you haven't yet, take a look at those.

And in many years of driving XJs and ZJs, I've found that wheel balance and tire roundness are the major contributors to DW. In addition, of course, to worn suspension parts.

ya sorry I wasnt even thinking about a stock. I was just picturing my rig in my head and how I usually adjust caster. sorry about that.

OK heres the synopsis from the alignment shop.

They could have charged me $80 for it but didnt, they found a bad axle u-joint on the passenger side. So I might as well do both of them while Im in there. Id also like to replace the axle seals as well just so I wont have to tear everything apart again.

How would a U joint cause the wheels to flop left and right causing death wobble? Seems fishy....... But I have been wrong millions of times.
Let us know if it no longer has the DW

Dunno, the tech said the alignment wouldnt do any good with a bad ujoint.

Maybe I'm wrong, but isn't the u joint the thing that connects drive shafts/pinions? How would that have even the slightest effect on hub/wheel/steering alignment?

This is a U Joint.


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I know what a u-joint is.

Could be a factor is possible vibration???

The tech said to bring it back when the u-joint is fixed

Death wobble is completely different then vibration. U joint would cause vibes, not death wobble .

Just so we are on the same exact page:

Death Wobble is a speed specific run away oscillation of the entire steering system. If you were to be watching the wheels of a vehicle experiencing DW, you would swear the wheels were possessed.

It is usually triggered by a bump ( or sometimes a small pea or a grain of salt ) in the road.
Once started, it increases in intensity (run away) until you are forced to reduce speed (because you fear for your life); then it magically just goes away (usually 20-50 mph slower than you were going).

I have never known wheel joints to cause death wobble.
* Worn wheel joints simply flop around between the caps. No affect.
* Stuck/Frozen wheel joints cause a parking lot speed pull/release on the steering wheel as the wheel joint tries to go though it's orbit...but can't.
No issues at speed.

Doing the seals requires removing the axles and carrier.
Replacing wheel joints only requires removing the axles.

Look for loose/worn stuff. On a vehicle with 100K, that could be just about everything. Tires and wheels are a huge factor. Out of round stuff really causes these solid axle vehicles to do cool things

When I replaced the track ber the DW was considerably less than what it was but the TB was not the culprit. Then I moved to the SS since it was completely gone and acted like an asp.

Im probably not going to do anymore freeway driving until the lift is on since all the bushings will be replaced at that time.

Anyways is the front diff a c-clip? Looks like the 3 12 point bolts seem to hold everything together and should pop out as an entire assembly. Then the carrier should just unbolt and drop out. Never had a D30 apart yet.

The axle will slide right out with the bearing hub. The seals are actually rather far in, near the pumpkin, and don't fail too often, if you're careful sliding the axle out and back in. I've replaced u-joints and hubs on all four of ours (some joints more than once), and I always separate the hub from the axle, and remove the hub first. Many will pull it all out in one piece, but I find it easier not to have to wrestle two clumsy pieces at once. While it's all out, you may want to consider replacing the bearings, too, especially if they've accumulated tons of miles.

Anything that doesnt fail often on these apparently is all broke in mine.

Last time I had the drivers side front lifted, a small puddle of fluid came out of the axle.

Not a bad idea on the bearings even though it only has 114k on it.