Anyone ever have their car make an extemely loud "bellowing" noise, similar to a foghorn? It only does it when i first step on the brakes and then it doesnt happen again. i have checked the pads and they only have about 12k miles on them.

 

rotors look good too?

 

Does this happen in all weather conditions? Sometimes my brakes can behave differently if there's a lot of moisture in the air. If I can help you work with a dealership to get this looked into (if you were to go this route), please let me know.
Sarah
GM Customer Service

 

Your pads might be worn down due to a known defect in the rear brakes. How do your rear rotors look?
https://www.cobaltss.net/forums/08-1...s-come-147233/

 

It's more of a not using the brakes as intended than a defect.

 

what brake pads you got in there? thinking they are not oem...thinking they are hawk.

 

Or this ^^

 

There is a known defect and it's not from misuse. I'm leaning towards the OP doesn't have that problem since he says it only happens when he first uses the brakes. Aftermarket pads also makes some noises. My hawk pads make some noise at first use.

 

i will check the rotors to see if they are warped or scored at all. i do know for a fact that the pads were replaced by the dealer i got the car from. However what brand of brakes they install i do not know

 

i will also add this commonly happens during rainy or moist days. is there a recall on the brakes? and what brand of aftermarket brakes would be better than the OEM Brembos? I was thinking of using hawk pads and rotors

 

I know exactly what you're talking about.

Mine does the same "bellowing" noise but mainly when I am stopping while in reverse. It is contributed to brake dust build-up. It's annoying but nothing serious. Just clean them up and it'll go away for a while.

My only suggestion is use different pads other than OEM. I replaced mine because I had the defect of the rear caliper piston sticking and it ate away my inner brake pad then chewed up the rotors. I used all OEM parts and it's done this since new, even with the original pads and rotors.

To sum up, it's just brake dust and the way the pad contacts the rotors and gives off this harmonic "bellowing" sound.

 

no there is no recall on the brakes - there is no known safety concern, its just a noise.
If you are only talking about a squal or horn type noise it is caused by vibrations or stick slip of the pads, rotors and calipers when you stop.
its a simple matter of removing the brake pads cleaning them thoroughly and applying ANTI-SQUEAL brake gel to the back of the pads where the piston and claw of the caliper meet the pads. Ive fixed dozens and dozens of these with this procedure.
If it only happens once during the first brake application of the day then dont worry about it, theres nothing wrong.
If you are concerned is to do with a grinding sound then you should take a look at your rotors for scoring there may be hard metallic particles in the brake pad material causing this, but your rotors would normally look scored.

 

Yeah there is no recall on the brakes (should be). BUT there is a known defect in the rear caliper pins sticking causing the rear rotors to get chewed up.

 

The caliper pins sticking isnt a defect, more so lack of maintenance.
They should be re-lubricated every 6 months.

 

yea thats exactly it! but oddly enough i dont have any brake dust (that i can see) on my rear tires. the fronts, forget about it...dustier than an abandoned house, drives me nuts.

but yea ill just give em the ol' spit cleaning.
thanks for the info

 

Some of the cars left GM factory line without proper lubrication so I consider that lack of maintenance on their end. Many other owners on here have had the same problem with the rear rotors and pads being shot at even less than 2k miles. No new car should have these problems at 2k miles. Anyways it's beating a dead horse.

 

But a lot of those people are the ones lightly dragging their brakes getting it all gunked up. They never stopped hard enough to clean off the rotors.

 

I know plenty of owners who didn't drag their brakes and had this problem. GM dropped the ball on quality control on some of these cars when they left the factory.

My dealerships service tech tried to say I must have been out yanking up on the ebrake while racing on a track. I never once did that or lightly dragged my foot on the brake as you say. They finally took apart brake assembly and my caliper pins were bone dry and my rotors were shot. They admitted fault on their end and gave me a "honorary customer" warranty repair.

You must have been one of the lucky ones who had no problems. I've had no problems for 40k miles after they fixed my rear brakes.