View Full Version : Diagnosing Suspension Noises

11-18-2005, 04:18 AM
This is a WORK IN PROGRESS. It contains mostly assembled information from various posters, and it is quite incomplete. I don't understand suspension systems very well, and I'm currently figuring out my own issues. The purpose of this thread is to provide a single thread containing methods of determining the source of the noise. Feel free to add information and to correct me.

So you hear a clunk, creak, rattle, or some other noise whenever you drive on an uneven surface or hit a speed bump. You think it's coming from your suspension, but beyond that, you're mystified.

It could be from the trunk:

Completely empty the trunk. Remove all items, including the spare, carpet, wooden thingamajig over the spare, etc. Make sure there aren't any loose items or trash in odd places, like the jack or spare compartments. If you're lucky, the noise will be from something loose or not properly fastened in your trunk. It could also be your trunk itself: check if the bump stops are in good condition and make sure it's securely attached.

If it's a clunk, maybe your bearings or bushings are going:

1. Jack up the offending part (front or rear) of your car and support with jackstands.
2. Grab one of the tires at 3 and 9 o'clock.
3. Try to wiggle the tire (hard). If it wiggles, your suspension arms are losing their bearings/bushings.
4. Grab the same tire at 12 and 6 o'clock.
5. Repeat 3, if it wiggles, I have read that your wheel bearings are going out
6. Repeat 2-5 for the other tire(s).

(stolen from hundredyardback)

If your wheels wiggle when you grab 3 or 9 o'clock, your control/suspension arm bushings (or bearings, depending on your model) are at fault. If they wiggle at 6 or 12 o'clock, your wheel bearings are at fault.

The 'best' test:

Position the car such that you can lie under it while a friend pushes it up and down. One method is to park the car such that the passenger side is substantially higher than the driver's side (for example, one side on the sidewalk and another on the street), but I think that parking in a place with a well/depression under the car is much smarter. Have your friend push on yoru car while you try to determine where the noise is coming from. Common sources include the sway bar to chassis bushings, suspension arms, or worn strut mounts.

Once you've pinpointed the source of the noise, trying seeing if there's any inappropriate play. Try to move the component (be firm, but don't force it) in a direction it shouldn't normally (i.e., towards and away from the trunk if it's a control/suspension arm, towards and away from the wheel wells for the strut rod), if it does, this suggests that the bushings or bearings are worn, and need to be replaced. If you can't pinpoint the source of the noise, apply this test to all of the suspension components in the general area of the noise.

12-23-2005, 02:17 AM
I recommend a set of ramps and wheel blocks for testing with a friend. Just drive the car up on the ramps (get the rear on ramps if the noise is there and vice versa), and block the other set of tires so the car can't roll off the ramps under any circumstance. Then have a friend push up and down on the car to help you diagnose your problem.