Noises going over speed bumps.

Dear Car Talk

Dear Car Talk | Feb 01, 1996

Dear Tom and Ray:

I drive an '89 Beretta and just recently I've noticed that when I drive over a speed bump, my car makes a loud "bang-bang" sound that wasn't there before. I asked my brother in law if he thought I should have the shocks replaced. He told me I needed to give it the "rear end/front end" test to find out. What you do is hoist your rear end up on the hood of the car, bounce the front end up and down, and then jump off. If the car continues to bounce, you need shocks. When I asked him if this was a scientific test, he said " every time." What do you guys think? Is this a reliable test, or is he just pulling my leg?

RAY: Believe it or not, Barbara, this IS a legitimate test for worn out shock absorbers. And I love the term "rear end/front end!"

TOM: Unfortunately, worn out shocks would never go "bang bang."

RAY: So in your case, doing this test is like prescribing a nose x-ray for a cold. The test is scientific. It's just not appropriate for the symptoms.

TOM: That noise is more likely caused by your springs. It sounds like the car is bottoming out. Your springs could be worn out or broken, or you could be missing one or more of the rubber cushions that prevent the springs from fully compressing and going "bang bang!"

RAY: Or it could be loose or unattached exhaust piece that's hitting the bottom of your car, or even a shock that's falling off. But whatever it is, I don't think the rear end/front end test is going to give you the answer.

TOM: Yeah. I don't care how big your rear end is, Barbara. Even my brother can't impose the kind of forces necessary on the front end to diagnose this kind of noise. This is going to require a trip to a mechanic who can put this car up on a lift and take a look. Good luck.

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