Originally Posted by TruTaing

I'm creating this thread because I see threads created on a weekly basis discussing the same kind of stuff over and over. I have gone through nearly every single noise (squeak or clunk) imaginable that can originate from the suspension. Im hoping this thread can be a collection of all of our best knowledge and become the place members can look for any sort of noise that may occur while owning a w203. Additionally, I am hoping to provide the most (cost) efficient means of pinpointing and resolving unwanted suspension noises.

I highly suggest purchasing a silicone based water resistant lubricant a spray and a grease - all suspension parts will have metal on rubber contact/friction and these types of lubricant last a LONG time and will not corrode your bushings.

Much of this stuff is straight forward to long time members, but hopefully this thread will help out our new members.

Front:

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Clunks:

1: Sway bar end links (50). This is the most common cause of clunks on the front suspension. The end link nuts may come loose and need periodic tightening.

2: Front Lower control arms (140). Take a look at the control arms and if they are leaking fluids - the bushings are worn and must be replaced. If you can find a hydraulic press, you can replace just the bushing, but most places will recommend replacing the entire arm because it can be purchased w/ the bushing in place.

3 (Aftermarket) (50): Adjustable sway bar end links. If your car is lowered (alot) and you have adjustable end links, you could potentially have your end links adjusted to be too long. The result is your long end link will knock with one of your lower arms. Not good. Shorten the arm or raise the car.

Squeaks:

1: Sway bar end link bushings (50). Spray with lubricant and go for a test drive. If the sound goes away, then you should replace the sway bar end links.

2: Sway bar bushings (20). Like all other bushings, these can get old and make noises. Apply lubricant liberally. Removing the brackets to get to the bushings is sort of a pain - there are very long bolts holding the brackets in place.

3: Strut bearings (115). This most commonly occurs when people have installed their suspension wrong after installing new parts. It has to be properly positioned in the strut tower otherwise it will make noises when turning and during driving. Additionally, this piece is known to wear down over time and compromise handling. Its a good item to replace and check if your car has noises from the front, but possibly the most difficult to deal with because it requires removing the entire strut/spring assembly.

Rear:

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Clunks (not many clunk issues from the rear):

1: Sway bar bushing brackets (50/60). Need to be tightened - happens all the time to people installing new hardware.

2: Sway bar end link (70). Needs to be tightened - happens all the time to people installing new hardware.

Squeaks:

1: Sway bar bushings (20). These bushings are pretty well exposed to the elements under the car and can often wear down and need lubricating or replacing.

2: Sway bar end links (70). These endlinks have two ball joints in them when are notorious for failing and causing all sorts of noises and should be replaced. Replacing the arm requires a special 12 sided tool.

3 (aftermarket) Adjustable camber arms (470) - These arms are exposed to the elements and have two metal ball joints. Most arms come w/ a certain amount of lubricant on the arms - I suggest putting on tons. You WILL have to eventually reapply depending on the weather your car sees.

4: Lower control arm bushings (70/80) - These get old and could use replacing. This is the most difficult and time consuming rear suspension squeak to fix. Spraying w/ a lubricant does not work well to test it, so replace these as a last effort to eliminating your rear suspension squeak. If you have a hydraulic press you can replace just the arm, but there is another bushing that attaches to the rear wheel hubs that should also be replaced at this time. Just replace the whole arm for simplicity sake.

5 (not really suspension but too common): Rear lug bolts are too long. When installing new wheels (OR the spare tire), be sure to use the proper length for your lug bolts. Compare the length of your new wheels and lugs with your stock wheels and lugs. They should both come out the back side of the wheels roughly the same length. If you installed bolts that are too long, you will hear lots of noise and probably lose the functionality of your parking brake. You will have to have the parking brake mechanism replaced.

Hope this helps consolidate all of these topics into one giant thread.

Thanks to glyn for providing the images.