I have read a ton of posts here about random front end clunks and how hard they are to diagnose. So I was wondering what the opinions would be on the following problem:

A mild clunk can be felt in the steering wheel of my 2006 TL AT when going over speed bumps at low speed or on uneven roads that cause some bounding in the suspension. Hard bumps like cracks and tar strips don't seem to cause any clunk. The car has 55k miles on it now and the problem has been getting worse since starting around 35k. I had an alignment check done a few months ago and it was fine and the tech said he could feel the clunk but it wasn't enough to diagnose the problem, saying to wait until it got worse (great!)

The other symptom is that the car becomes noticeably more unstable at speeds over 55, feeling kind of like a shopping car with bad front wheels, meaning it doesn't track like it should. No pulling, it just takes extra attention to keep it in the lane. The steering wheel itself it still tight, no slop can be felt when turning the wheel left or right. The tires are original and have about 3/16" on them, which is low, so I might go ahead and replace them anyway and see if that trues up the road feel, but I doubt it will help. The shocks were replaced at 45k (I drive on bumpy roads obviously!) and the clunk didn't get better or worse.

So the list of suspects would probably be tie rod ends, ball joints, steering rack, motor mounts (would that cause a steering problem?), wheel bearings, etc... Since the labor cost of inspecting the tie rods and ball joints (most likely bad parts) is probably (?) the same as replacing them, I'm wondering if I should just buy the parts on-line, replace them all, and take a gamble that one of them is bad? Otherwise it is a crap shoot to just have someone pull everything apart looking for the one (or more) bad ones. The bill could easily be $1-2k to swap everything out if they can't find an obvious problem, so buying the parts myself would save some cost. A mechanic around here is $80-120/hr.

I also plan to look at the lower control arms this weekend, some of the posts said the bushings sometimes split. Not sure if that would result in a clunk, but it could probably account for the loose feel on the road.

Is there anything else I should look at? I hate to wait until the clunk is so loud and the car is so loose that a deaf and blind tech could find the problem.

Thanks for any help

 

Most likely it's the compliance bushings on the lower contol arms. Due to my bodyshop's incompetence I was lucky enough to have every bushing in the front end replaced at different times so I got to see the result of each one.

Mine developed a light clunk at 20,000 miles which got worse over time. When I upgraded the front swaybar, I found loose bushing brackets (that bolt to the subframe). This helped a little. Later, I had one of the compliance bushings replaced and it helped. This last go around had both compliance bushings replaced and for the first time in 70,000 miles I have no clunk whatsoever.

I would start with compliance bushings and go to swaybar bushings, these are the most common noise makers. I would especially look at the compliance bushings since the handling is off. When mine were torn, they could literally align it, drive around the block and recheck it and it would be off again.

If the swaybar mounts or end links are bad or loose, it will cause the car to feel more unstable at speed. It will shift the handling bias greatly torward oversteer. Basically the equivalent of installing a 50mm RSB lol.

 

Thanks. I took a look at the control arms today and there were very small cracks in the bushing towards the front of the car, one crack front and back. They were only 1/8" or so deep so I would have a hard time believing that could cause the problem.

It really sucks having a sports sedan that's not fun to drive on the highway for over a year and having to just wait while some part slowly wears out. Too bad no one has a way to find the problem, like a sensor they could stick on the suspension to pinpoint the source of the clunk.

 

Actually, after reading one of the long posts on the bushings, now I'm thinking that may be the problem. I have had a problem of vibration on hard braking for a long time, just figured it was warped rotors even though it is inconsistent. The only question is would a minor tear in the bushings also cause a clunk?

BTW, I checked both front wheels and they don't have any top/bottom play so the ball joints aren't obviously bad. The tie rod ends seemed OK to my untrained eyes, I couldn't get anything to move. All boots look fine.

 

I thought I would add a follow up for anyone who found my post. I replaced my tires and that mostly cured the wandering problem. Turned out that 2 tires (at least) had significant cracks in the sidewalls. I went with ContiExtreme DWS and that solved that problem. Good thing I didn't have a blowout! I read that it is common with low profile tires to have sidewall cracking, especially if you hit curbs or run a lot with low pressure. I tended to keep the EL42's a little on the low side (31-32) so they rode a little softer, so maybe that made it worse. But I got 55k miles out of them, so I'm not complaining.

As for the clunk, I am still undecided whether I want to pay to replace the bushings (1.6 hrs labor to remove control arms + ? hours for installing bushings + alignment) . The clunk seems to have diminished a little after I readjusted the steering wheel position, so I'm wondering if it just wasn't tight. I'll keep an ear open to see if it keeps up.

BTW the Continental DWS are very soft, handle pretty good although not super sharp, and have medium road noise. Haven't been in rain yet.

Matt

 

IHC...Can these bushings cause a very bouncy ride + clunk + sloppy handling + slight loose feeling of steering wheel?

 

I have the same symptoms/problem. I'm wondering if bad motor mounts can cause handling problems.

 

for the front end clunk, REPLACE your front endlinks! that should solve ur problem. one good pothole can destrot the bushings in them. i had the same problem and since i replaced them, no more clunks....it was VERY annoying too...lol

 

I'm having the same problem... had a shop tell me that it was a bad shock but it doesn't happen on every type of bump - more like an event that involves the whole car. Seems to be coming from the center tunnel area....

 

I had the same clunking noise from the passenger front when going over bumps at lower speeds, replaced the side motor mount, problem solved..