2002 STS vibration

Ron

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My 2002 STS has Continental tires on it and it vibrates above 100 km/h.
I had the wheels balanced twice but no significant change.
Could this be a serious problem?

:confused:
 
Is there uneven tire wear indicating a suspension problem? Are the tires properly inflated to the recommended pressure? Do you hear a metallic popping sound when turning or going over bumps?

Since the tires are balanced there's likely a worn suspension part such as a ball joint(s) or perhaps a wheel is warped—which is less likely but possible.
 
100 km/h is about 60mph, that's not very fast to have a vibration. If you have a bad tire, you might be able to feel a woble at very low speed (less than 25 km/h) or jack up the car where you can have a helper slowy spin the wheel so you can look at the tire and wheel for abnormalities. A good tech should have spotted this while balancing. If something is not obvious, it could be an out of balance rotor or drive axle. A local speed shop might be able to help you with that, or at least tell you who can.

Mac1 and mark 0101 both have good suggestions, things people often overlook.

Good luck!
Keep us updated, we want ot know what you find.
 
vibration

Thanks for the suggestions guys. I'll follow up on those.

As far as uneven tire wear goes, they all look ok.
Initially they were inflated at a too high pressure indicated by the message on the dash. I deflated them to 38 psi which was the max.
When the wheels got balanced the second time, the tech deflated them to 30 psi which is the recommended pressure.
I do not hear any metal popping sounds when driving over bumps. It behaves normal without any weird sounds.
I also tried driving very slowly and it behaves excellent. No vibration and no sounds.

The thing I forgot to mention in my first posting is that when I put it on cruise at 115 km/h on the expressway, I can feel the vibration coming up, then it disappears for a few seconds and then it starts again, so it's not constantly present.
I even considered the asphalt conditions but I think I'm going too deep with that one.
Most of the time when it vibrates and I let go of the steering wheel, it vibrates. However not always. Sometimes I feel the car vibrate without the steering wheel virbating the way it does when indicating a typical bad front wheel balance.

Anyway, I'll check the things you guys suggested and keep you up to date.
 
Another possibility is the front rotors are warped or brake pad residue transferred onto the rotors due to overheating brake pads. Are you using ceramic brake pads or cheaper quality brake pads? If brake pad residue transfers onto rotors it’s possible the brakes themselves from time-to-time are rubbing against uneven rotors causing intermittent vibration. I’m guessing of course as to what may be the problem, but if your suspension is not worn then you may want to check rotors for warping or unevenness. Have them slightly resurfaced, if necessary. Recently, it has been suggested that ceramic pads may overheat causing rotors to warp and/or pad residue to transfer onto rotors.
 
If the rotors are warped, I think I should feel it when braking.
The pedal would slightly vibrate but it doesn't. I should also feel it in the steering wheel when braking and it does not feel any different.
From gut feeling I think I should start off with checking the wheel for being warped and check play in the suspension parts.
Anyway, I'll check all things that you guys suggested and leave nothing to the unknown.

Thanks,

Most likely I'll know a little more tomorrow.
 
Unfortunately, I have had something similar

In my case, the previous owner overinflated the tires, which must have separated the belts and allowed the tread to shift. Once this starts, the tires must be replaced. As you described, the vibration lessens and worsens about 65 - because the tires are not exactly the same diameter, and part of the time cancel each other out.

I still love my caddy!
 
I checked out the rims using a dial indicator with an accuracy of 0.001".
I jacked up the car and spun each wheel very carefully, multiple times to check repeatability of the results per revolution.
I got the following warp results for each rim:

Right front: 0.008"
Right rear: 0.035"
Left front: 0.010"
Left rear: 0.012"

The results might not be totaly correct because the indicator was not attached to the car or any suspension part. So if the wheel would not have been mounted correctly and straight, I would have seen some warped results on the indicator too.
I cleaned the surfaces and the rims before mounting them after which I took the results with the dial indicator.

I think I can rule out the rims can't I?
I tried to check for play in various suspension parts but it seems to look fine to me.
The next thing will be the rotors.
 
I don't think 0.035 is enough to cause a problem. I was really talking about something with the tire or wheel you could spot with your eye, but precision doesn't hurt.

A tip I learned a while back is to cover your hand with a rag and run it along the tread surface of tire. It somehow helps in feeling unusual wear.

You can also try rotating your tires front to rear to test for changes in the vibration. Mark them with a wax pencil on the inside so you can keep track of where they started from easier.
 
I checked about everything and visually can't see anything being wrong. Neither do I feel any play in the suspension parts.
I tried moving the wheels from front to rear but the vibration is the same or even a little worse.

IHHESTON: As a matter of fact, when I just had bought the car and drove home, I got the message on the display that I should check the tires.
At home I checked the tires and they were all way overinflated.
I deflated them untill 37psi just below the maximum.
Currently they're at 34 because I thought 30 would be a little too less. The tires look like they're too flat.
Is there a way to determine whether the belts have come loose and whether the tread shifts?
The tires are about half way worn so I could drive them for a while.
When I put new tires on the car I need to be sure that this is the real cause of the problem.
 
I think I found the vibe

I got 2001 DTS with the same vibe....I think I found it....

Been having a problem with the front axle. 6 months ago tried to replace....but could not get the hub out of trans.

Yesterday, had new axle and axle shaft puller here. Got the axle snub out of trans. Snub has very strange wear. (see pic)

I think in this car the trans shaft bushing is gone. The bad news is this bushing is not available.....you have to buy the complete case extension..... plus select washers etc....mess...

So the new axle is in. It was a slightly different part. Noticably heavier on the transmission side.

Now the vibe is worse with the heavier part....ahhhh.....clue.

Got this theroy from another post on net....similar GM FWD vibe issue...

"The bearing/bushing/case in the trans axle, where the axle enters, was worn and the axle was loose.
At high speeds the axle would bow out at the inner CV joint (run in an elliptical fashion).
This whipping effect caused the vibration."


I think this is exactly whats going on. Please note the damaged bearing surface on the snub. (see picture)

I can pry on the axle snub and it moves.

My car is going in for hail damage this week. So the trans will get fixed next week.


Logan Diagnostic
www.ledfix.com
www.airbagcrash.com
www.logandieselusa.com

shaft 001.jpg
 
Interesting web sites Logandiagnostic! GM was very secretive about the SIR module recording capabilities way back when ('87?). I didn't realize the word was out.

Thanks for the post on the vibration. Good news/bad news kind of revelation. I still hope Ron's problem is tires, it would be a lot easier to solve
 
I haven't put on new tires yet. I started looking at different brands and I'm still in the deciding fase. The thing is, if it's not the tires then the price ticket of the tires will be added to the repair costs of the real cause.

What's not clear to me is, when the axle runs in an elliptical way, shouldn't you feel the vibration constantly?
When driving on the expressway, from time to time, the vibration is completely gone but nit always comes back and running the car at about 130 km/h to 140 there seems to be less vibration as compared to about 100 km/h.
 
Ron said:
...IHHESTON: As a matter of fact, when I just had bought the car and drove home, I got the message on the display that I should check the tires.
At home I checked the tires and they were all way overinflated.
I deflated them untill 37psi just below the maximum.
Currently they're at 34 because I thought 30 would be a little too less. The tires look like they're too flat.
Is there a way to determine whether the belts have come loose and whether the tread shifts?
...

If the tires all appeared very round when you checked the wheels, rather than a little uneven, it may not be the tire, but I sure couldn't afford for it to be anything else.

As a matter of fact, you might consider: setting the tire pressure as indicated on the driver's door sticker, then have a friend/significant other drive the caddy while you observe the tires from another car. Pick a nice empty multi-lane road, pass the caddy on one side then the other, and see if there is any uneven tread movement as the tires roll at a couple different speeds, including the vibration range. A pair of cell phones help the process. Disclaimer: Obey all traffic laws, drive carefully, maybe even have another pair of individuals ride along to handle either driving or cell phones.

I found out that my local tire place used incorrect weights on my STS, apparently there are more than one kind of clips on the hammer-on style. I threw one under braking the other day, and stopped back by. It solved one vibration problem REAL easy. Learn something new every day...
 
Get your tires "Road force" balanced. Those machines are the best of the best. Look it up on google. I think their site even has a locator to find one near you.
 
tires....

The tires on my 2001 have been Hunter road forced balance.

My vibe also comes and goes. It is obvious from the picture the axle is causing the vibe on my car.

My car is fine up to about 64-65 mph. The theroy is at that higher speed the worn bearing/ half shaft kind of launches into critcal mass....it goes where it wants to go.

"The bearing/bushing/case in the trans axle, where the axle enters, was worn and the axle was loose.
At high speeds the axle would bow out at the inner CV joint (run in an elliptical fashion).
This whipping effect caused the vibration."


It is pretty easy to check how much loosness is in the hub. With the car on a flat surface....simply pry on the inner axle hub....you should have very little movement.

If the axle is parked on a incline or anything that loads the axle up. You will not see the looseness of the axle bearing.

I have heard.....the early cars used a babbit shaft bearing.....latter cars used a brass bearing....mine has metal to metal transfer on the axle snub. I have not confirmed the babbit /brass bearing issue yet....
 
When I saw the picture of the axle I got scared more than a little.....
So this is what I did in the mean time:
I located a professional tire expert centre.
I went there yesterday and gave them the whole story and wanted to either designate the tires as the root cause or rule them out.
First the mechanic took it for a drive which was a good idea I thought.
He found that the car was vibrating and also jumpy left to right when he drove over a small bump or something similar.
Therefore he thought there was somehting wrong with the suspension but couldn't find anything.
He decided to rebalance the tires and the first 3 were dead on when he rechecked them afterwards. With the fourth one, they called me in to have a look at it.
Guess what, the rim is bent. I was completely surpised by what I saw. I measured the rim with a dial indicator but only on the outside and it was straight there.
On the inside however the rim is bent so much that when he spun it on the balancing machine and lifted the cover, you could easily see the rim pop up at one point and further more, the tire even bumps up at that point.
The mechanic thought the tires were ok in his opinion, which was honest because I told them that if the problem was caused by the tires I was ready to buy new ones.
He inflated them with nitrogen because it might lessen the effect a little but I can't say it does.
I don't know what brand of balancing machine it was but I think I can find out.
I'm hoping that the rim is the real cause of the problem and that I do not have a problem with an axle.
I'll check the axles tonight just to be sure....

Thanks for the info guys.
 
I checked both axes at the hub. Like you said there's very little movement and both are identical.
 
I also visited the road force website. I can see now why you guys recommend this system. It will be my next choice if the wheels have to balanced.
There is indeed a service center close by that uses a system like that.

Thanks
 
Ron- That is actually good news. Bent rim. They can be sent off to be repaired....see: http://www.fixrim.com

I have personally used this company several times with excellent results.

As for the '98 and latter Seville/ Deville line. These cars are known for being wiggly cars. Some of us have been chasing the 65-75 vibe for years.

In my case, I think my axle is the issue. That being said, my car is at the body shop for severe hail damage right now. I think there is a very good chance it will be totaled (severe hail damage on trunk, roof, hood, complete passenger side). Dealer says car is beyond paintless dent removal. Many panels will need to be replaced. The repair is on hold right now waiting for the insurance company to re estimate the car.
 
That would be a pitty if the car is totaled. Especially if you put a lot work and money in it.
Must have been really severe hail to damge a car like that.

I didn't know the rims could be repaired. Thanks for the website.
I just hope that this is the real and only cause of the vibration. With my luck there will be something else contributing to this.
We'll see. First I need to have the rim corrected.
 
I've got a different rim on the car.
It's way better. I think there is still a little vibration but if I can't get rid of that, I can live with this level of vibration.
However I'll find a local shop with Hunter balancing machine and have the wheels balanced on it.
Don't know exactly when that's gonna happen.
I'll keep you updated.
 
Ok, I got the wheels balanced with a Hunter Road Force machine.
No better results. The comment was: "if you do not feel any change, you're betting on the wrong horse by checking the tires".
The car vibrates and the vibration comes and goes. I feel it in the seat and also the steering wheel vibrates. Sometimes it's completely gone for just a brief moment.
It also happens that I only feel it in the seat and not in the steering wheel and vice versa.

So, the suspension is ok, no excessive play in the axles, wheels are balanced, tires are ok, no vibration in the brake pedal, no excessive wear on the tires, indicating an alignment problem....I'm completely lost.

If anybody has suggestions that have not been tried yet, please let me know.
 
I think I finally found out what is causing the vibration in my car.
Yesterday we had a hot and sunny day with temperatures of around 98.
When I drove home I hardly felt any vibration. There was some but way less than what I normally feel. I felt the tires when I got home and they were hotter than on other days.
So I'm thinking that the tires are causing the vibration. When they get hot the rubber softens a little becoming more flexible and the road vibration is better absorbed by the tires.

Does this sound possible at all or am I going nuts??????
 

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