The wobbly-shake-vibe

I did some searching, and couldn't find anyone in my same situation, or at least with a description of their problem that matches mine. Here is my problem:

Around 55mph (plus or minus 3mph) I get a vibrating shaky wobble sort of feeling that feels like its coming from the front end. I sometimes feel it in the middle as well especially after hitting potholes (which in Virginia is about every 15 seconds). I just replaced my trac-bar 200 miles ago, and put a new steering stabilizer on. This is nothing like the death wobble I had before I replaced the trac-bar, because this shake goes away after about 5 seconds. Its just very unnerving to have that "I'm riding a bicycle at 75mph and my front tire just started swapping" sort of feeling on the highway in your Cherokee.

Here are a few things I think may be connected to the problem:

1. Its an adjustable trac bar; do I need to try adjusting it some more?
2. I have a stock rear driveline on 3" of lift with no SYE. I've seen guys running 4.5" lifts with no SYE, but also heard of people needing them after 2" lifts.
3. I recently had an alignment done (about 150 miles ago), and the tech told me my steering was rusty as hell, and hard to adjust. The print out I was given showed that the car was aligned, but I'm wondering if the adjustments didn't "stick".


As far as specific details about the setup in case anyone needs them to troubleshoot:
3" Rusty's lift (full springs, no blocks/spacers, shackle lift, or add-a-leafs)
Rusty's adjustable trac-bar (TB122) which adjusts for 2.75" to 5" of lift.
Stock Steering, with new steering stabilizer from Rusty's
Stock drivelines
Stock axles
Auto tranny 4.0L

Thanks for any help with this problem. Its not that I don't like rollercoasters and all... I just don't like driving one to work!

Have the tires balanced...even if you just had them balanced and them balance them again. Swap the wheels front to back, see if it smooths out. That 3-4 MPH over/ under 55 is real common, and the fix is usually tire balance.

I'd try to control the rust in the suspension and if you're concerned have the TRE's replaced too. Your lift setup is similar to my XJ and I played hell trying to get the bigger tires to balance correctly on stock rims (with 31's). But easy for me to say, not rusty here. POR 15 or even Rustoleum can do wonders if kept up.

Small highjack.., what is POR 15?? Paint?
Tires can get worn out of round, (especially since no two tires seem to weigh the same, have the same diameters, let alone a set), and can develope a hop, or vertical type shaking. The suggestion to check your TRE's is spot-on. The comment to check balance is good. The process of elimination of all varibles is a hassle, but necessary. They do seem to be additive, and therefore it's sometimes necessary to do a complete front end check. Up, and down, plus, side to side, equals wobbly-shake. Vibe can be worn lugs. Thats what's going, the latter, on my DD. I did not rotate tires timely, hence lugs are worn out more than others on the same tire, and I now have vibe.

A rust treatment....before you need it or after there's already rust there. Yes, paint, essentially.

Here's their website. It's pricey but pretty much resolves rust issues, at least for 3-4 years at a time.

http://www.por15.com/

What is a TRE? Tie rod end? Next paycheck I was planning on putting in either beefier steering or a new front sway bar with some homemade quick discos.

I was thinking I may be having a lower control arm issue. I pulled them out, and inspected them and the bushings are toast. Ordered a new set for 90 bucks. Anyone able to describe what bad LCAs usually feels like?

Yep. Tie rod end.

Bad LCA bushings (with me anyway) was a definitive "clunk" going over even small bumps, like the little ones in the middle of the road.

After I changed them out I can barely feel those little bumps

If you tap on the brakes does the wobble go away while still at the same speed?

If so, you might have brake pads that aren't properly seated. The pads can wear grooves in the steering knuckle slider plates and get misaligned with the rotors, which can cause some serious chatter. Even clips won't fix the problem if the knuckles are grooved. The solution is to put a wire-weld bead in the notch and then file/grind it smooth.

Just another possibility.

montanaman said:

If you tap on the brakes does the wobble go away while still at the same speed?

If so, you might have brake pads that aren't properly seated. The pads can wear grooves in the steering knuckle slider plates and get misaligned with the rotors, which can cause some serious chatter. Even clips won't fix the problem if the knuckles are grooved. The solution is to put a wire-weld bead in the notch and then file/grind it smooth.

Just another possibility.

Click to expand...

Braking doesn't alleviate the wobble until I reach about 50. Today in the interest of science (MAD SCIENCE!) I accelerated instead of braking and going up to 60 killed the wobble. I don't normally like to drive over 55 on the highway (dangerous drivers out here, and I like all the reactio time I can get), but I drove 65 all the way to work -- 13 miles -- and the car only shook for about a half second after I would hit bumps; it would shake right to left maybe twice, and a lot less violently than at 50-60.

I think I'm going to get a tie rod in addition to the LCAs. Has a sway bar ever done something like this to anyone's ride? It looks like mine could use new bushings all the way around.

I think 99% wheel balance.

Had this several times with the MJ and all the XJs.

If it gets shakey around 55 and lets off when you coast down to just under 50 it has been wheel balance every time for me.

Balance and rotate.

Heading to a do it yourself shop right now on base and they also do wheel balancing. Supppose ill have them spin these little meats around while I'm there!

i have the same problem at 55 and u speed up or slow down it goes away to. i know my UCA's bushings are going out. i put on a 3.5 tough country about 4 months ago and had a very slight wobble even wit a stock tb that pulled the axle to the driver side about 1.5". but i put on a rustys adj tb and now its a pretty bad dw at 55 and bump str. alignments and rebalance are prety much a must wen changing anything in the front!

Rebalance and new LCAs! Problem solved. I found when I took the old arms out that the bushings had torn all the way through. The Tool Box is now riding MUCH better. Have you adjusted that rusty's trac bar yet? I need to lengthen mine a bit and I'm wondering if I can do that without detaching it.

False alarm... still shaking now at 65. Much better considering I rarely go 65. Starting to get frustrated.