MountainStone

So I have developed a vibration in the steering wheel. Feeling along the front tires as they spin I can feel the leading edge of the tread blocks; this leads me to believe they are cupped. My car is 10 years old w/ 80K miles and I wonder if the struts may be bad.

How can I check if my struts are bad? Do they have to be removed from the car? Should I just replace them based on age/mileage?

To clarify: when replacing struts, am I really just replacing the shock absorber portion of the assembly and reusing the spring or is the whole assembly replaced as a unit (this is my first car with struts).

Thanx!

MountainStone

I am disheartened at the lack of response from a normally helpful forum.

Does nobody know how to evaluate struts?

Am I being shunned?

dylan6879

only way ive ever known to check would first be visually check em out see if they look damaged. also on each corner of the car push down on the car then release and if it bounces more than once they r more than likely bad

TruTaing

Are you certain you have cupped tires? It usually makes a loud "wobbling" sound when driving w/ cupped tires.

Replacing the strut alone does not involve replacing the spring. Just the shock/dampener.

I am no expert on cupped tires, but from what I understand, its either the tires that are faulty or the suspension itself. If your tires have not been on the car long and the cupping has occurred, then you can be pretty sure that its the suspension causing the issue. But if the tires are relatively new, and they are cupped, it could be the tire's fault.

If you chose to change the front dampeners, you might want to consider changing out the springs and top strut bearing also. Look at brands like Bilstein and/or Koni for for dampeners.

Also, the front lower control arms bushings also are notorious for wear - this might cause unusual changes in your suspension geometry + unusual tire wear. Search the forum for many past experiences.

Good luck.

MountainStone

Thanks for the reply. There is no visible damage or leak. I wondered about the 'bounce' test, which is how I checked the shocks on my old '70 Chevy Nova (guess some things never change).

Thank you for the reply. It's my understanding the way to check for cupping on a tire is to feel along the tread; if the leading edge of the individual tread blocks are raised and your hand doesn't pass smoothly from one tread block to the next the tire is cupped. Not an exact science, but I swear I can feel the edge of those tread blocks.

I recently replaced a driver-side control arm due to a bad ball joint. That bad ball joint introduced a lot of slop in the driver-side suspension and I am hoping that caused the cupping, but I don't want to buy new tires only to have them ruined due to the struts also being bad. The car has 80K miles so it is conceivable the struts need replacement, but if they are still serviceable I need to save that money. That's why I am asking if there is a way to tell if the struts are bad. The tires are about a year old with prolly 10K miles of use and the vibration started about a month ago, which lead me to find/replace the worn ball joint.

I agree with your advice to replace the top strut bearings if the struts are replaced, but are the coil springs also a wear item? I am happy with the stock ride height and feel...

jcnash

Did you do an alignment after replacing the control arm joint? That could be your problem.

Unfortunately, the only "proper" way to check struts is to remove them from the car and push down and measure the rate of return of the struts to its fully extended position. The closest you can get to checking while its on the car is the bounce test. For most modern shocks the 2 bounce test is the standard. So you push all the way down on the front/rear of the car right in the center. It should bounce back up, then slightly back down and come back up and STOP. If it continues to go back down one more time, your struts are shot/nearing its end of life.

Midnight Koop

+1

i had choppy threads b/c i forgot to align once... that could be it

tommy

Since you have a C32, it might be a good idea to post something in the W203 AMG C32/C55 section, to see if anyone there has had the same problem, since they would have the identical setup as you.

MountainStone

Thanx for the reply. I'll try the bounce test; seems like a LOT of trouble to completely remove the strut to check the action of the dampener.

Thanx for the reply. I hope the cupping/choppy treads are a result from mis-alignment due to the faulty ball joint on the control arm I replaced. I just don't want to buy new tires only to have them develop cupping because the struts are also bad.

Thanx for the reply. I posted here because this board receives a LOT more traffic than the C32/C55 board and I *think* all W203s have the same McPherson strut suspension configuration (though different models have different spring rates and different dampener specifications). Thank you for the suggestion, though!

FrankW

Cupping of the tire a lot of time is just the tires. You can run one brand/model of tire and it will cup bad and then go to another set of different tire and no cupping. I.e. My w204 was on the PZero and they cupped BAD and then the time comes to replace them with sumitomo the cupping never happen again.

What tire are you running?

Also if you are on the stock c32 suspension still i would suggest you lower it with after market springs or find a set of c55 springs. The standard US spec front spring for the c32 is too high and causes the car to wear out the outside of your front tire much faster because of the car's caster setup as well as the height gives it a bad almost positive camber.

Btw, alignment for the 203 you are basically just doing the TOE if you dont have the camber/caster bolts. I wouldnt bother with alignment unless you are having excessive tire wear or the car not tracking straight due to TOE angle.