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By abriley - 12/9/2006 3:59:49 PM
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I'm posting for a friend because he is skeered or something so here goes:
97 TJ 4 banger with cheap 4" Super Lift that had new front lower control arms. He took the front sway bars off because of the winch plate he bought interfered with the sway bar.
The lift kit has been on about 1.5 yrs and this past fall he had some death wobble start about 40mph or so. It would go away so he just lived with it.
After Hump N Bump in early November, a new problem has emerged. When he uses the brake, the front dives real bad and the vehicle swerves side to side in the lane; he has almost hit several cars.
My YJ dives as well but I believe that is because of the soft shocks and shackle reversal. I have a manual tranny so I usually don't hit the brake hard. He has an auto tranny so he brakes harder. My YJ wants to veer to the right under extreme braking but it just veers to the right. His TJ is going back and forth.
Any ideas?
I believe his control arm bushings and track bar bushings should be replaced but we're trying to gather some more info before throwing money at it. Thanks.
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By paulyj - 12/9/2006 10:02:42 PM
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what kind of trac bar is he running
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By Jerry Bransford - 12/9/2006 11:52:56 PM
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Swerving when he hits the brake sounds like it could be a severe case of bump steer. Did he recently install a dropped Pitman arm or perhaps he has an RE 1610 trackbar (which uses a dropped upper mounting bracket) without a dropped Pitman arm? If he has a dropped Pitman arm without also having the RE 1610 trackbar, he needs to reinstall the OE Pitman arm. TJs cannot have a dropped Pitman arm otherwise, at least not until you get to a huge lift height like 6" or taller. Or if he has the RE 1610 without a dropped Pitman arm, he needs to install a dropped Pitman arm. If he has one, he must have the other. If he doesn't have one, he can't have the other. Make sense?
For the street, his TJ should use an antiswaybar. If his winch mounting plate isn't humped to fit over the OE antiswaybar, he should either at least go with a Currie Antirock or other antiswaybar that fits inside the tube just aft of the front bumper. Or buy a winch mounting plate that was properly designed for a TJ as most of them fit just fine over an antiswaybar.
So far as the Death Wobble goes, have him tighten the lower trackbar mounting bolt to 55 ft-lbs. and get the front tires rebalanced perfectly. Those two are the most common sources of DW. Then have someone steer back and forth while your friend watches the entire front-end and steering while sitting in front of the Jeep. That will allow him to see anything moving that shouldn't be which can also cause DW or at least make the DW worse.
Finally, have him make sure his toe-in is set somewhere between 1/16" and 1/8" per the instructions at http://www.4x4xplor.com/alignment.html as improper toe-in can make the front-end more suceptible to DW. HTH. 
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By Squatter - 12/10/2006 3:51:57 AM
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Diving to one side could be one of the front brakes. My jeep was doing a lot of diving, etc and then all of a sudden one of my brakes is metal on metal! Ugh! Darn! I have the Warn hub kit on my D30 and one of the rotors was shot to shame. What a pain! Anyways, diving and what felt like a lot of rear steer in now gone (I have Detroits front and rear).
Around spring of this year I suddenly experienced death so bad it was a stuggle to drive the jeep home.
After doing all the stuff people tell you to check I got it to be tolerable, but there was still a little going on. I was getting a bunch of noise coming front the joint where the drag link and trackbar come together. I called RE and got the parts to basically rebuild that join. BOOM! There we go! We are back to that stock feel again with 4+ lift.
BTW, my jeep is a 98 TJ.
Good luck!
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By abriley - 12/10/2006 11:17:05 AM
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He is running a dropped pitman arm with the stock trackbar. According to the SuperLift instructions, we drilled a mounting hole for the trackbar to move it over 1 inch I believe. So, by doing this, he didn't buy an adjustable trackbar.
I agree with you about the swaybar. He bought a cheapo winch and "universal" winch mounting plate at CostCo for $300. The only thing universal about the mounting plate that it fits in every dumpster in the world. It is complete garbage but I cannot do anything because it's not my money.
Just wondering, why has it been okay for around 1 year then this fall/winter the dw has shown up?
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By Jerry Bransford - 12/10/2006 2:30:46 PM
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Your friend really should reinstall the OE Pitman arm. The dropped Pitman arm is definitely a major contributor to the problems he's having. This is a subject I know well, no rumor spreading going on here. I personally went up to 5.5" of lift with the OE Pitman arm without bumpsteer and only installed a dropped Pitman arm last year when I also installed a dropped upper mount for a new RE trackbar. You need to match the Pitman arm to the trackbar. If one is dropped, the other must be dropped. You can't have one dropped without the other being dropped. Either (Pitman arm and trackbar) both need to be dropped or neither can be dropped.
And DW can appear any time, do use the suggestions made above as they will very likely take care of it.
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By abriley - 12/11/2006 6:41:43 AM
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We'll give it a try. sucks though cause I don't think we saved the original pitman arm.
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By The Original Club Rubicon - 12/12/2006 10:11:10 AM
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Now i don't claim to be a crowd favorite on this website, and you can take my advise into consideration only if you want to. It's your choice.
But Jeep Death Wobble is nothing to mess with, and it could be a number of things that can cause this, but most times on a T.J. it's one thing, and usually the most expensive part. If after a visual/Manual inspection for bent or loose front steering components check out o.k.
9 times out of 10 on a T.J. i would say check your power steering gear box, let you, or your buddy get into the jeep, (with the parking brake on!,) and you put your hand beneath the steering gear box, (KEEP YOUR HAND CLEAR OF ALL MOVING PARTS AND PINCH POINTS!) but while your buddy turns the steering wheel back and forth from left to right, you will more than likely feel a heavy, or even very slight thump in the gear box, this means that somewhere along the way your buddy decided to hit some rough terrain while still in two wheel drive, and he probably hit a rock which put a strain on the gear box gear mesh, now the steering box gears have slack in the mesh, thus hence forth comes the famed Jeep Death Wobble...
You can add or take off drop pitman arms, add adjustable track-bars, and tighten crap all day long, this may help out a little, but the slack will still be there. Replacing the gear box will solve the problem all together...
Ask your buddy if his Jeep always starts wobbling all over the road at a certain curve, or even straight away on his daily route, it is at these certain points in the gear box where the teeth have slack, thus when the tires hit a bump they throw the steering wheel out of control which causes the Death Wobble.
hope this helps,
The Original Club Rubicon...
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By jollymon - 12/12/2006 11:41:26 AM
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About half way down the first page here is best (and probably most informed) explanation on the intarweb I've seen:
http://www.jeepaholics.com/support/topic.asp?ARCHIVE=true&TOPIC_ID=996
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By Jerry Bransford - 12/12/2006 2:26:48 PM
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quote:
Originally posted by jollymon
About half way down the first page here is best (and probably most informed) explanation on the intarweb I've seen:
http://www.jeepaholics.com/support/topic.asp?ARCHIVE=true&TOPIC_ID=996
Death Wobble is one of my more favorite subjects and that is the best writeup/explanation of it that I've ever seen. I saved it for future reference. Who was Joel who wrote it?
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By The Original Club Rubicon - 12/13/2006 3:12:18 PM
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quote:
Originally posted by jollymon
About half way down the first page here is best (and probably most informed) explanation on the intarweb I've seen:
http://www.jeepaholics.com/support/topic.asp?ARCHIVE=true&TOPIC_ID=996
Yawn...
Check the gear box, you'll find that i'm right...
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By Mike Simpson - 12/13/2006 8:46:06 PM
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And Tony,
With respect to your brake diving, that is a common occurance on YJ's with a shackle reversal, under hard braking or any braking for that matter, the front axle will actually "roll" under, and the nose of the vehicle drops. The harder the braking, the more pronounced that is.
Besides having to get a long spline front driveshaft, that is the second complaint I have with my SRS. But, I still love it's effect on uphill climbs, climbing obstacles to outweight that brake dive.
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By jollymon - 12/13/2006 9:56:14 PM
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quote:
Originally posted by Jerry Bransford
quote:
Originally posted by jollymon
About half way down the first page here is best (and probably most informed) explanation on the intarweb I've seen:
http://www.jeepaholics.com/support/topic.asp?ARCHIVE=true&TOPIC_ID=996
Death Wobble is one of my more favorite subjects and that is the best writeup/explanation of it that I've ever seen. I saved it for future reference. Who was Joel who wrote it?
Somebody Al knows at DC that obviously has engineering knowledge of the issue.
quote:
]Originally posted by Al Bsharah
A friend at DaimlerChrysler has some first-hand experience re-engineering the dealth-wobble syndrome - so I'll try to get him on-line to talk to you about this. It had to do with changing the bushing characteristics and shapes... I'll see if I can't get him to fess up some info.
-Trav
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By abriley - 12/15/2006 3:50:32 AM
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Yeah, I found the thread where Al's buddy posted up.
Mike, I love the benefits of my srs. The diving doesn't bother me. I can deal with it.
The gear box thing is very interesting.
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