Today: The Rattling GMC Jimmy

Dear Car Talk

Dear Car Talk | Apr 30, 2015

Dear Car Talk:

I drive a 2001 GMC Jimmy with about 230,000 miles on it. Recently, I drove it cross-country from New Orleans to Portland, Oregon, with a U-Haul trailer in tow. We had a few problems, but we completed the journey. Before we left, I had the mechanic in New Orleans give it a good lookover, which turned into replacing brake lines and installing a new emergency brake. However, we've recently noticed that there is a clicking noise coming from the passenger side of the car when we brake, though it seems to happen only when the following conditions all are in play: Going downhill + pressing the brakes + turning right. Any thoughts on what it might be? The car is such an old man at this point that I'm hesitant to put too much money into getting it fixed if it isn't a problem that will lead to me careening off a cliff in the near future. Thanks!

-- Becki

Well, I can't rule out the cliff scenario, Becki. Start by checking all of your wheel nuts. Since you had brake work done, you may be thinking "brakes" first, but maybe the guy didn't tighten your wheel nuts and you have a wheel that's getting ready to fall off. Hey, it happens.

Assuming it's not that, then if you're lucky it's something simple, like a loose brake pad. If it tends to happen when you're stepping on the brakes lightly, then it could be just a loose pad. When you step hard on the brakes, there's really no room for pads to rattle because they're pushed up hard against the rotor. So if it's just during light or moderate braking, your mechanic can try installing a hardware kit that's designed for rattling brakes. It's called -- get this -- an anti-rattle kit.

If it's not a loose pad, then it could be something more dangerous. I would assume that when your mechanic did all that brake work in New Orleans, he would have noticed if an entire caliper were loose. But maybe he was suffering from a crawfish hangover that day and missed it. So you definitely want to have another mechanic take a look.

If it's a loose caliper, or a caliper bracket that's not attached properly to the steering knuckle, you'd be more likely to hear the rattling when you go over bumps, too. Because the caliper is a larger part and would be banging up against its bolts, it would sound more like a knocking, rather than a rattling.

If your caliper were to fall off, you'd have trouble stopping the car and trouble controlling the car, because one wheel would be stopping while the other would not be. Then we're back to that cliff scenario.

So I'd advise you to check the wheel nuts, and then take it to a mechanic you trust right away, and just let him inspect the brakes.

Hopefully, he'll rule out anything drastic, and if it's just benign pad rattle, (which I'm sure our pharmaceutical companies are working on a cure for right now: "Do you, or someone you love, have BPR?"), then you can decide if you want to fix it or just live with it.


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