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kachink 02-16-2013 04:20 PM

Another Vibration Issue
Hi guys, sorry for the WOT but I could use some advice on a 2005 TJ and I wanted to be complete. Itís all stock, approx 75,000 miles. It gets taken out on the local fire roads a couple of times a month, so the suspension has had more abuse than a mall crawler, but itís still mostly a road vehicle.

Last year we started getting a vibration at 50-55 mph. I read that speed sensitive vibrations were usually tire/wheel related. I did several things and everything seemed to help for a while, but it keeps coming back.

- I rotated the tires and noticed they were wearing unevenly Ė too much toe-in.
- I adjusted the toe-in to about 1/16Ē difference with the tape measure method.
- After a week or so I re-adjusted the toe-in so it was 1/32Ē difference.
- Dry steer test showed axle moving sideways, with a lot of slop at the axle end of the track bar. I ordered a 3 piece poly bushing and a real 10mm bolt to replace the stock rolled one that is undersize where it goes thru the bushing. When I got the bushing the rolled center piece was so poorly made that there was more slop with it and the new larger bolt than there was with the old bushing and the smaller bolt. I ended up using the new bolt with the old bushing.
- Got a new set of tires. The tire shop checked the alignment and said it was ok at that time.

At this point the vibration was almost non-existent. It took braking within the speed range to start it and it was not nearly as bad. It's been about 8000 miles and it has steadily gotten worse. It still only happens when braking around 50-55 mph. Itís not so bad that it feels like somethingís going to break, but itís bad enough and steadily getting worse. Tire rotation didnít seem to have any effect and tires seem to be wearing evenly.

I did another dry steer test this morning and the axle is still moving back & forth some. I have maybe 1/32Ē of slop at the axle end of the track bar. The rubber on the TB bushing and the control arm bushings have some small surface cracks, but nothing catastrophic. I canít see movement on any other joints.

My thoughts on next steps are;
- Replace the TB bushing with either a new stock style rubber bushing or make a new center tube for the plastic 3-piece bushing that I bought. (Does anyone know why they roll the center section of all these bushings instead of using tube?)
- Replace the lower control arm bushings.
- Replace the upper control arm bushings.

Am I on the right track? Is there anything Iím missing here? Should I do these steps one at a time in that order, or just break down and do it all at once?

Thanks in advanceÖ

durango-bob 02-16-2013 05:40 PM

I would do them one at a time just to see the effect that each has. Sound you are on the right track.

rjacobs 02-16-2013 05:46 PM

Is it a vibration in the steering wheel or a vibration in your butt?

If its in the steering wheel than you are on the right track(front end). If its a vibration in your butt than its most likely in the rear end and you may be looking in the wrong place. At least thats what my old man taught me years ago and so far he has been pretty much right. Steering wheel=front end, butt=rear end.

kachink 02-16-2013 06:35 PM

rjacobs, the vibration feels like the front end, (at least that's what I've always thought) but the steering wheel does not shake back & forth like I've sometimes seen with alignment issues. In my mind I attributed that to the axle moving laterally as opposed to the wheels trying to change the direction they were pointing and moving that up the steering linkages. I'll have a look at the rear bushings though, thanks.

durango-bob, I'd rather do them one at a time, especially if I can avoid the dreaded upper control arm bushings. I'm just thinking that because the things I've done so far have helped temporarily, then it's worsened suggests that it could be an accumulation of wear in all the different parts. I'm afraid as I fix one it may put more stress on the rest and it may return again.

kachink 10-15-2013 10:34 PM

Well the vibration has gotten worse. I've avoided this long enough and finally started making some changes.

- Replaced the track bar bushing with a Moog rubber one (not the 3-piece). When I was finished the axle end seemed solid, but had a little movement on the frame end. On a scale of 10 to 0, 10 being how it was, this made it about a 7.

- Replaced the lower CA bushings with Raybestos Professional Grade Clevite. This made a big difference, maybe a 2-3 on the 10 scale but it steadily got worse over a few weeks.

- Replaced the Track Bar with a Moog. BTW, the Moog DS1235 that is supposed to fit 97-06 is about 1/2" - 3/4" longer than the stock bar, so the axle is off center now. (It's stock height.) It's vibration free now up until about 70mph. At that speed it will vibrate a little, until you brake, then it's bad.

My next step is to replace the upper CA bushings. I've searched, but I can't find a definitive answer on the bushings. Is the front bushing on the axle the same as the rear bushing in the arm? The Chrysler parts list shows the arm (with bushing) then a rear bushing as a separate part (2 req), but no part number for the front bushing. Rockauto has various brands, but only one part number for the upper. They sell the Raybestos lowers in pairs, but the uppers as singles. Does anyone know if the axle end & frame end use the same bushing?

Does anyone have any next steps if this doesn't solve the problem?

Thanks in advance...

Eckoh 10-15-2013 10:40 PM

My 03 has hated 47mph FOREVER i can go over 50 or under 45 but in between the front end wobbles... sometimes jeeps just have their quirks. However do keep it in check my wobble got bad and at 40k i had to replace the hubs.

the hubs might be something you want to check, the way i was taught to check them was lift the front end and put a lever of some sort under the tide from the side and lift to see if you have any play, if it wiggles top to bottom it could be the hubs.

kachink 10-16-2013 08:08 AM

Eckoh, thanks for the tip, I'll check it out. I have done the check for ball joint play and can't see any.

Anyone know if the two bushings for the front upper control arms are the same?

samiam_va 10-16-2013 02:12 PM

I just replaced mine. The bushings on each side of the CA are the same. Upper and lowers are not. Lowers are larger. I would also recommend changing bolts (Use grade 8 fine thread) unless yours are in good shape and over torque them. The front end on the axle are the most difficult to remove. I went with poly and burnt out the rubber.

Akela7 10-16-2013 03:38 PM

I had a bad wobble issue (the front end would hop up and down uncontrollably when I went over a bump) that alignment and balancing only reduced not eliminated. The place that does my alignments replaced both the track bar and the steering stabilizer eventually, and that pretty much eliminated the problem, but I still could feel a shake over some larger bumps. Quite by accident (Jeep parked on an uneven surface) I noticed that the sway bar link on the driver's side was completely in two pieces. (the swivel joint on the top had come apart) I don't know how the alignment place missed that, but I will say that when the jeep was parked on a level surface, the joint went back together so you could not tell it was broken. $23 from my local NAPA later and I had a new sway bar link which I replaced myself and the rest of the wobble problem went away. The track bar and steering stabilizer did need replacing, but I am fairly sure that the broken sway bar link hastened their demise, so check your sway bar links too. (I haven't replaced the shocks yet, but I will in a month or so because all that shaking could not have done them any favors either.)

The_Dealer 10-16-2013 05:36 PM

Does it only do it when braking? Have you tried checking your rotors?

danromaine 10-16-2013 05:47 PM

I went through everything, balancing tires, checking suspension, etc. I knew it wasn't rotors but had to do my brakes and found that the right front hub had play. Loosened the nut and re torqued the nut to factory specs and my vibration went away. My vibration only happened between 45-50 MPH

kachink 10-16-2013 08:01 PM

Thanks for all the input! I haven't checked the rotors or the hubs. It vibrates a little at 70ish mph without braking but gets really bad when applying the brakes at that speed. Braking at any other speed is wobble-free, so I don't think it's the rotors. The hubs are a good idea though. I'll give them a look-see. I'll check the sway bar too.

samiam, thanks for the info on the bushings. I'll get them ordered tonight!

kachink 11-16-2013 04:01 PM

Man, this is wobble is kicking my ***!

I've replaced the front track bar and all 8 front control arm bushings. Doing that moved the point where the shake happens up to about 70-75 mph and it was very minor if not braking.
This morning I broke loose the big hub nut on each side and re-torqued to 175 ft lbs. I was going to do the same for the 3 bolts on the inside of the hub, but I couldn't get the 1st one broken loose, so I figure they are ok. Now it's worse.

Now it rides smooth as long as I'm going on a smooth road in a straight line. But if I'm in the 65-75 mph range and hit a bump, turn the wheel, or brake, then the vibration starts. If I have to go around a curve at that speed it will start to vibrate going into the curve and stop when I straighten out again. If I'm going straight and hit a bump at that speed will vibrate a little then stop. If I brake in a straight line at that speed it's the worst, but it stops if I let off of the brake.

I can feel the whole front end shaking through the floor, it's NOT coming mainly through the steering wheel and my initial dry steer test showed no slop in the steering components. I re-checked the toe-in and I've got slightly less than 1/16 difference front to back across a 40" span on my home made jig.

The sway bar and connections are intact.

My hunch is that the bushings that I replaced were worn (probably partially from the vibration) but they weren't the root cause. Replacing them just moved the speed that it happens up because the new bushings control it better. All I can think of that is left is replacing the hubs and/or the ball joints, but neither show any sign of being worn that I can tell and I'm getting tired of throwing parts at this. Does anyone have any suggestions?

durango-bob 11-16-2013 07:42 PM

High speed vibs are usually caused by tire balance or driveshaft balance.

kachink 11-16-2013 09:11 PM


Originally Posted by durango-bob (Post 17764865)
High speed vibs are usually caused by tire balance or driveshaft balance.

That makes sense because it's resonating at a certain speed. This actually started with my last set of tires though, and tire rotations didn't change it with either set. I haven't investigated drive shaft balance. Would turning or braking affect it if it was drive shaft balance though?

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