Dear Tom and Ray:

My front brakes, which are just a few months old, make a very strange noise -- on occasion. These "occasions" are never when I drive to the dealer or the mechanic. I've had mechanics drive with me, and the noise never occurs for them. There is no pattern to when it will make the noise -- not wet pavement, not hot or cold temperatures, not hard braking. Nothing I can figure out. The sound: The closest I have been able to describe it is the sound of a seal barking. And it does this in a rhythm with the rotation of the wheels, slowing as the car stops. It is very loud and very scary. But the car stops fine, and the guys who have driven it have taken off the wheels and say there's nothing wrong with the brakes. They have no idea what the noise is. Do you? -- Ken

Tom: A seal barking, eh? Aruuu! Aruuuu! Well, we have seen a few rare cases in the shop in which a beached seal has taken up residence in the vicinity of the front axle. But since you don't live near the ocean, Ken, we can probably rule that out.

Ray: Assuming that your mechanic has also ruled out the potentially dangerous front-end components (wheel bearings, ball joints, etc.), then I'd put my money on a brake disc or brake drum that's warping (you don't say what kind of car you own, so I don't know what kind of brakes you have). The fact that the noise occurs at the same speed as the spinning wheels means that a brake pad is scraping something each time the wheel comes around. And what it's scraping is the raised (or warped) part of the disc or drum.

Tom: So why does it happen intermittently? It probably has to do with temperature. As the disc or drum heats up, it subtly changes shape. And during a certain part of that "change process," you get the noise. Before it hits that "right" temperature, the brakes are fine. No warping, no pulsing, no screeching, no growling, no barking. Then you get into that zone where the noise occurs. And then, as the brakes continue to heat up, the disc continues to change shape and the noise disappears again.

Ray: The bad news is it's almost impossible to figure out exactly which component in your brake system is causing this problem. And unless you can narrow it down to a specific wheel, you'd have to replace virtually every disc, drum and pad to make the noise go away.

Tom: The good news is that you can safely ignore the noise. Since the mechanics have physically inspected the front end (we assume) and the brakes, and have determined that the calipers are free and the slides are not seized, you can be quite sure that this is not a safety problem.

Ray: So that leaves you two practical options, Ken. Spend $600 replacing your brakes. Or spend $600 on a phenomenally good stereo system for the car, and then turn it up whenever the noise occurs. I know what I'd do.

What's the best way to warm up your engine in the morning? Find out by ordering Tom and Ray's pamphlet "Ten Ways You May Be Ruining Your Car Without Even Knowing It!" To order, send (check or money order) to Ruin, P.O. Box 536475, Orlando, FL 32853-6475. You can also order online.

© 1998 by Tom and Ray Magliozzi and Doug Berman Distributed by King Features Syndicate, Inc.

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