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Brake rumble

2017 gmc Acadia limited, 27k miles. We bought it a month ago and have a 1 year bumper to bumper warranty. After highway driving of a few hours occasionally rumbling noise on braking when pulling in for gas or rest stop. It is not felt in the pedal, and seems to be coming from the rear. It happened a few times in a row on the trip up, and the trip back, then went away. I hope it breaks the brakes and gets covered, any similar experiences? I cannot replicate the situation. Checked the wheels for heat at one stop, all were warm, not as hot as Mcdonalds coffee.

You do have the warranty, why not take it in? Could be the pads or rotors or even a sticking caliper.

Only thing I can think of would be a stone or debris in brake pad crevice or stone in between rotor and dust shield. My Buick had a terrible grinding noise at slow speed at 2000 miles. When I drove it in for warranty they heard it and thought it sounded like a fried differential. Turned out to be a stone half the size of a pea stuck between rotor and dust shield.

So I took it in for the 3k mile oil change, and trans fluid flush at 30k miles. Dealership getting back to me tomorrow, rusted rotors on the front they said was causing rumbling. Analysis when car bought, 9 mm on front pads, 11 on back 3k miles ago. After 3k miles was advised front pads down to 4 mm. Called their support guy. First question do you ride the brakes? No I said, I got 80k out a set of brakes on my trailblazer before it got rear ended at 200k. So he is meeting with the original inspection mechanic and the oil change mechanic tomorrow am. Now I am not going to get killed as new pads and rotors was a $400 estimate, but curious to see how this plays out. CPO 1 year bumper to bumper, brakes excluded I am sure.

CPO= Certified Piece of ?

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Got a call today, an offer to cover 1/2 the cost of front end pads and rotors.

Do it yourself for half that or take the $200 offer. Unless you want to contest the original 9 mm on the front. I suspect that that value was actually 4 or 5 mm, but half off isn’t too bad. You’ll need brakes anyway. Also, if you ride the brakes, wouldn’t the rear pads be worn similarly? Did they measure those? If they fudged the fronts, why not the backs? You might ask them to measure the rear pads unless they did it already.

The rear pads were at 11 when purchased, down to 10 now. I don’t do brakes. $380 was the price, so my cost $190. I got an average of 80k miles on the trailblazer, but my wife has the Acadia as her car. She is from New York, and I feel like a bobble head when she drives, speed up for red stoplights and signs gas on gas off etc. I let her highway drive on trips because cruise control takes over, but when we go out together in town I drive. I do not know about pad wear for riding the brakes affecting front more than rear. So theoretically the rears will last another 18k miles.

And how did they explain that . . .

If a vehicle gets driven regularly . . . as in several days a week . . . I don’t see how you could have a rusted rotor under normal circumstances

if they truly are rusty on the surface that the brake pads contact, then all is not well, and you’d be wise to figure out what is going on

if a caliper, hose, hardware, etc. is messed up, I could see a rotor getting rusty where the brake pads contact it. Otherwise . . . not really

I am assuming you don’t live in salt country. Rusted rotors , stuck caliper slides, and frozen calipers all due to salt are a constant problem around here. My 2012 Toyota Camry, bought new in Dec. 2011 with on;y 54,000 miles on it just has its second front brake job and is due soon for it’s third rear. The front needed pads, rotors and calipers, all due to rust. I could not retract either front caliper enough with a very heavy duty 8" C clamp to get new pads in. All the brake hardware was replaced at each brake job and I use coated rotors. I also do not ride the brake and I time the lights to get there on green.

My son bought a new 2007 Hyundai Sonata, it needed a rear brake job at 16000 mils and a year and a half. He was told,no warranty on brakes, finally got them to pay half. He moved to Florida 10 years ago and it was drive down there for 6 more years without a brake job. His 2014 Sonata , bought new in Florida has 56000 miles without a brake job.

Even though both of those cars have stainless steel clips between the slides on the fixture and the pad ears and I use Sylglide on the front and rear sides of those clips, salt gets under the clips and rust bubbles on the fixture jam the clips so hard against the pad ears the the pads cannot retract when you take your foot off the brake. If they made stainless steel backed pads and fixtures, I would buy them.

There was or is a company in Clarence NY That started modifying Corvette brake calipers by enlarging the piston bores and putting in stainless steel linings. I think the nam,e of the company was Stainless Steel Brake.

They called yesterday want to inspect the brakes and systems, no new brake day picked out yet. * appreciate the level of concern. Wildest hope they pick up the whole tab, best hope the find something wrong.

So I got to see the brakes today. The inside of the front rotors have a one inch band on the outside of rough looking stuff, next inch mild, inside looking good. Outside of rotors looking fine. So I get 50% off a new brake job. Calipers did not seem to be a problem. I asked if there was a good better best option, no, though the service advisor did say they were coming in the future. Bought in april 3k miles gone from 9mm to 4cm. I guess I m happy enough though I imagine someone with more whatever could do better. Could have been a measurement error they said, 30k total miles. Bad rotors in production I think, thanks for listening.