Front End Vibration

I've been chasing a front end vibration for months now on my 2000 LeSabre Limited. There is a slight vibration in the steering wheel at speed and it is enough to rattle seat belt clips etc. It is worse sometimes than others at the same speeds. I've replaced wheel bearings, tie rod ends, drive axles, tires, wheels are true and balanced, engine mounts seem good, and alignment. The struts seem fine as well. I'm starting to think it's a harmonic balancer maybe. Any ideas?

About the only thing left that has not been replaced is the rotors. What to you torque the lugs too?

I was thinking somewhat the same thing, but the vibration seems worse at sometimes vs others. That's what led me to believe that it might be something dynamic like a balancer that's going. I'll check the runout on the rotors. As far as lug nuts go, I usually spin them on with an impact and snug them up with a t-spinner. Should I really torque them to spec? Thank you for your reply.

Well, I only asked asked because the 2 ways to warp a rotor is either by riding the brakes or more often than that, overtorqueing them.

All the others you say you've coveed: balncing, bearings and tires (seperated belts)

Ah...it didn't occur to me that overtorqing could damage a beefy rotor...I'll check it out tonight. I guess from what I've done so far new rotors are relatively cheep! Thanks again. I'll let you know how it turns out.

$00.02.... What are the chances its the rear?
Did you get new tires or rotate them?
Can someone watch the tires from another car at speed?
Harmonic balancer would go away or change if you rev the engine at speed.
When you touch the brakes does it quit or change?
When you turn slightly does it change?
A bad belt on a tire may look better pulled off on a spinner than when loaded with vehicle weight.

Good Luck..

if that dose not work then heres a test that i do is to jack up each front wheel with a floor jack and have some one to spin the wheel by putting it in gear. if their is anything out of balance the wheel will jump up and down. p s jack under the frame next to the ball joint and get the wheel a inch or so off the ground, floor, pavment etc. do each wheel seperately.
on the left wheel thier is a balancer on the drive axel do not rule it out as it could be part of the problem.

New tires all around...same shake.
New drive axles...same shake
New wheel bearings...same shake
New rear shocks...same shake
Rotate tires...same shake
Turn left or right corner/change lanes...same shake
Hit brakes...same shake (no float in pedal either)
Lower airpressure...shake is better, but just a bandaid
Rev engine, speed up, slow down, drop to neutral...same shake
Tried watching from road...seems to be related to left front.
Spun both wheels on the rack without much sucess at identifying something seriously wrong.

The last thing I can think of that it could be a bad bearing in the drive spline from the transaxle...I think that's one I may have to live with though.

I'm intrigued about a balancer on the left axle? Where is it? What does it do? How do you adjust it/measure if it's out of adjustment?

First of all, I have spun the tires with the car off the ground as someone suggested, be very careful though to get them up high, I'm more comfortable with 4 inches or so off the ground. If it starts jumping while the vehicle is on the stand the tire could contact the pavement if its not high enough and it would then throw the vehicle right off of your jack stands. Also don't allow the speedometer to read faster than about 35mph or so because with no compressive load on the tire it could explode at higher speeds. If you search on this topic you will see a lot of forums about this vibration issue on GM H body vehicles. A lot of us have written extensively in them. The bottom line is that this car is extremely sensative to vibrations being passed through the engine cradle (sub-frame) and strut towers. The debate that goes back and forth in the other threads usually deals with why there is such sensativity in the design. I tend to feel vibration more on this new pavement they seem to be putting down on major highways now, that really dark rubberized blacktop. It turns out that the pavement does seem to end up with bumps at regularly spaced intervals that cause a vibration at speed, you can actually see it in the surface of the road if you are driving slowly in traffic. It seems that our cars by design are particularly sensative to that sort of vibration. In order to reduce the symptoms as much as possible I changed out my tires for bridgestone turanza LS-V's, the V rated tires are held to much stricter tolerances during manufacturing to acheive the high speed rating and tend to be better balanced as a result. I run a cold tire pressure on those tires of about 33 psi, due to their slightly lower load capacity compared to the stock michelins. I replaced both front struts with the KYB units and installed bendix rotors on all four corners. Rear shocks were replaced with the monroe max air units. It is absolutely critical that you torque the wheel nuts properly to 100 lb-ft being careful to tighten them in the typical star pattern to avoid warping the rotors. Overtightening the wheel lugs will warp your rotors and could potentially damage the studs. After doing everything mentioned above I have absolutely no vibration now on older paved highways. I still pick up a slight vibration on the newer rubberized blacktop at around 70mph, but nowhere near as serious as it used to be.

Fantastic, thank you so much for the great writeup. I have noticed that the concrete pavement does in fact make a significant difference in the amount of vibration in general. What is interesting is that I have three of these vehicles within two years apart and only one of the three has this noticeable of a problem and all have the same tires. I'm inclined to change out the struts and rotors to start with and go from there. Thank you again for your help.

You know, people take all different approaches to doing they're own auto maintenance. I never approach this stuff from the standpoint of saving tons of money. Essentially I try to take a look at what it would cost me to replace struts for example at a dealer or mechanic's shop, and then i think about how much more i could do on my own for the same money. It's good to save a few bucks, but i'd rather spend most of the savings in labor on more new parts during the repair process. I don't just replace the strut, I replace every potentially worn part that I remove, after choosing high quality replacements. When I installed the KYB units I bought used strut tower assemblies on ebay and then re-built them outside the car with the new KYB struts. Everything made of rubber got replaced, also the bearings and mounts were replaced. The only parts I re-used were the springs. Once I had both towers re-assembled outside the car I simply un-bolted the old ones and replaced them with the new ones. In the end it was still cheaper than dealer work. In my opinion if you don't end up with a result that is better than what a dealer would do then it isn't worth the time and effort or even the money for that matter. Someone mentioned using cheap rotors in this thread, but is it really worth the effort to save a few bucks now. You'll end up spending that twice over if they warp in a few months. I havn't even scratched the surface of my master plan for the brakes on this car, I needed rotors and pads to hold me over until I could afford performance parts. The Bendix products are pretty good OEM replacements, but they're probably the bottom end of what I would be willing to install. I am usually really satisfied with how my maintenance work turns out on this car, but I attribute a lot of that success to the quality of parts and tools I use when I do it.