I recently bought a 2006 Equinox with 113,000 miles on it. The problem I am having is that it makes an unusual ratcheting sound (not real loud, but annoyingly noticeable) when the brake is applied. I've isolated it to the left front wheelwell area. At first I thought it was metal on metal, but the pads are good and rotors look new. It almost sounds like sticking a playing card in and out of the spokes of a bicycle wheel except it sounds plasticky and hollow and rhythmically intermittent, not constant. Or that ratchety sound of a roller coaster going up the track. It makes the sound predominately as I am coming to a stop and slows down as the car slows down (one to one speed related ratio). It'* strongest at say 10 mph to zero. It will even do it if I let the car creep while easing off the brake. It will not make the noise at all with no brake pressure applied. And as for high speed, if it does it all, I can't tell. It doesn't seem to do it in reverse either. I cannot duplicate the problem on jacks; it seems to have to have the weight of the car on it to make the noise. I've looked for things rubbing (i.e. boots, shrouds, etc.) while on jacks and in gear but to no avail. I have not removed the hub or replaced parts yet. I am at a loss to further diagnose this problem and any suggestions would be appreciated. Thanks.

my guesses would be tires, rotors or maybe wheel bearing. i would rotate the tires first and see if it moves

I thought of bearings, but noise is very regular in the sense that I know it will come around again at a certain wheel rotation (vs. random rattling or a constant whine). I will rotate the tires/wheels to see if it follows. Thanks!

could be a flat spot in the tire if it sat a while

Does this equinox have plastic hub caps? Ive seen alot of those making noise. Usually the plastic ring that goes between the hub cap and steel rim falls off making a clicking, plasticky sound. If you take the hubcap off and the noise goes away thats obviously your problem.

Are you sure it is coming from the front? If it was from the rear it could be a dragging park brake shoe. The park brake shoes are seperate from the brake shoes and they interface to the inside of the rotor.

I like the idea of taking the hub caps off to see if the noise goes away.

After a painstakingly close inspection, I was able to duplicate the problem on jacks. I think I can narrow it down to the wheel bearing on the left front side due to possible disc thickness variation. With just the right amount of brake pressure, the disc drags ever-so-slightly through the pads and thereby loading the bearing and causing the noise. I will change the front wheel bearings, discs and pads and update this thread accordingly.

Just a final update: I replaced both front wheel bearing assemblies, discs and pads. This solved my problem. The left bearing had a rough spot on it. If you replace the hub bearings, I recommend getting a hub puller (I used an OTC 7208A, $37), an assortment of pry bars and a hand sledge. A butter knife and a hammer actually helped split the mating surfaces. Good luck!

thanks for updating