Owner-reported complaints naming the brake system, filed with NHTSA
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Reports naming service brakes, the antilock braking system, brake hoses, master cylinders or the parking brake. Every record below is an owner-reported complaint about the 2021 GMC Acadia submitted to NHTSA — not a confirmed defect, not a recall and not a manufacturer bulletin. 18 reports on file name it.
Complaints are reports submitted by owners and drivers to NHTSA. They are not verified and do not establish that a defect exists.
Shown in the owner’s own words, exactly as filed
My brake pedal got stiff when I was driving. I had zero control of my brakes. I was informed by a GMC dealership that my BRAKE BOOSTER blew up causing my brakes to stop working and metal shrapnel to be sent into my engine. My 2021 vehicle is a complete loss. GMC has done NOTHING to help me.
I was driving and all of a sudden my break pedal was inoperable. It was stiff and unable to be used. Luckily I was only going 40 MPH. I pulled into a parking lot and my car started shaking and apparently the metal parts from the vacuum pump blew into my engine, which completely wrecked my engine. I nearly could have died and now my 2021 car is completely destroyed.
On March 27, 2026, I experienced a complete brake failure while driving a 2021 GMC Acadia in a school zone at approximately 3:00 PM. When I pressed the brake pedal, the vehicle did not respond. I attempted multiple times, including using the emergency brake, which did not activate immediately. The vehicle remained in motion for several minutes in an area with children and parents present. The emergency brake only engaged after approximately 30–45 seconds of repeated attempts. I was forced to steer off the road to avoid a collision. The vehicle had been inspected at a GM dealership on March 16, 2026, just eleven days prior, where the brake system was evaluated and no issues were identified. After the incident, the dealership diagnosed a leaking vacuum pump, which is a component that supports the brake booster system. This failure occurred without warning and created a dangerous situation. I am concerned this may indicate a broader safety defect.
ABS Modulator failed leaking oil. Loss of braking Repair service found the same problem. Part was scrapped.
The Vacuum pump on my 2021 GMC Acadia failed causing my breaks malfunction. This Problem was confirmed by a certified mechanic that repaired it. this is in conjunction with the NHTSA recall issued under N192268490.
I was driving down the road and all the sudden my breaks locked up. Like I had to stand on the break with both feet for it to barely stop. After getting it to the repair shop they said my vacuum pump exploded. My problem is it’s very well taken care of car and absolutely no warning light was on. I had no warning at all just all the sudden wouldn’t stop. Now I’m 7,600 in the hole because of this and very upset my not even 5 year old car is having these problems.
Front right brake hose was entangled around the front drive shaft and tore the brake line apart causing catastrophic brake failure. Car had only 19000 miles on the odometer odometer.
Breaks make loud noises when cold. OEM PADS and ROTORS. New with 8k of miles
Brakes will start Grinding on front wheels
Taken from service report; customer states brake pedal some times sinks to the floor and brake fluid on driveway. Tech performed brake fluid check and found that the brake fluid leak is coming from the left front and right front caliper hose, caliper hose has rub marking, making contact with cv boot. Tech replaced the left and right front brake caliper hoses and performed brake fluid fill and bleed, rechecked the operation of the brakes-brakes are working as design Also on service report: Left front cv axle leaking, left front outer cv axle boot is torn, replaced the c axle assembly. Not on the report is that the service manager Informed me that I should not have driven the vehicle in but had it towed in. Service performed under warranty at Linus Cadillac Buick GMC, Vero beach, Fl
The contact owns a 2021 GMC Acadia. The contact stated while reversing out of her parking space, the contact heard a squeaking sound coming from the brakes. The vehicle was taken to an independent mechanic and the brakes were replaced; however, the failure persisted. The dealer was contacted and stated that there was an upcoming recall and to wait for the recall. The manufacturer was contacted and stated that the vehicle needed to be diagnosed. The vehicle was not repaired. The failure mileage was 26,000.
My brakes are awful. They sqeak and sqeal constantly. I've taken it to Ken Ganley Buick GMC several times. Prior to that, it was taken to Nick Abraham BMC. The dealerships are able to duplicate the sound and problem over and over again. None of the dealership representatives are able to offer a solution other than paying out of pocket to replace the brake pads because the material the brake pads are manufactured from are falling short. There is no way the brakes are functioning the way they were designed. Thankfully, I have not been in a situation where I need to slam on my brakes but I am not confident that they would do their job in an emergent situation. I have a toddler and a new baby on the way. I purchased a big SUV with the mindset that it would keep my family and I safe. We have leased several GMC products over the years and have never had an issue like this. We will absolutely not be renewing our lease to prove our loyalty to this brand. The fact that I'm being told the only way to fix the manufacturers problem is to pay out of pocket and fully replace the brakes on my vehicle that is 1.5 years old with 28k miles on it, is absolutely absurd. We are willing to give GMC the opportunity to make it right. At this point, I'll be honest, I doubt anything will even be addressed.
As I was stopped in line behind a car at the ATM, my foot slipped from the brake, I quickly placed it back only to find that I ended up going forward. I quickly moved my foot more to the left for the brake only to end up going forward even faster hitting the car in front of me. I then put my left foot firmly on the brake. Now with both feet on the brake the car is climbing up the car in front of me and not braking. Finally, I put it in park and cut the engine. The whole front end of my car is crushed. Now 5 days earlier my husband had a similar incident when he was parking the car and thankfully only hitting the curb. Looking at the brake pedal you will find that there is a rubber edge hanging down on the right side. IF YOUR FOOT SLIPS BELOW IT while crossing from the accelerator going right to left, YOU WILL NOT hit the brake but will continue to press the accelerator. In fact, if you raise your foot upward, you will only raise the brake. The only way to get to the brake is to get out from under it by going toward the accelerator and then back to the left. This action does not work in an emergency! I believe this rubber edge is too large is a safety hazard. We are still in the process of assessment by insurance, body shop and GMC.
My emergency parking brake keeps engaging on its own, as I come to a stop, jeeking me forward. I never even put it in park, but it just engages the parking brake in a forceful manner. At a couple different times, while going at about 40 mph, the car starting shaking terribly, slowing the vehicle. The check engine light came on as well as both parking brake lights on the dash (the indicator light saying the parking brake was on and the indicator light saying there was a problem with the brakes). It felt light the vehicle had engaged the parking brake with I was driving and was dragging the parking brake. I have been having problems with the brakes with the vehicle and have taken it to the dealership a few times for this issue. They only kept it overnight and told me there was nothing they could do because it didn't happen while they had it. I have a fractured back and am disabled, and this issues actually hurts me when it does it.
While driving through intersection auto braking system activated for no apparent reason . Could have caused a crash due to sudden unexpected braking. No warning lights or alarm noted during or after event. Dealership was unable to find any problems with the automatic braking system.
The contact owns a 2021 GMC Acadia C1. The contact stated while driving approximately 40 mph, the parking brake engaged independently. The contact also mentioned having difficulties steering the vehicle. The vehicle was restarted and it resumed to normal. The vehicle was not diagnosed or repaired. No further information was available. The failure milage was unknown.
Electronic parking brake is setting itself without you doing it even when parked on a completely flat surface. Voice activated assist is going off while driving down the road without you hitting the steering wheel button. 1st dealer I took the car to refused to even address issue because the car didn’t throw a code even though the parking break issue happened while in their parking lot. 2nd dealer at this point has had the car for a total of 16 days. They tried to tell me the parking break was normal, manager at actual dealership told me it definitely was not normal, and they don’t know what to do about voice activation going off. It has now been at dealerships 3 times for this issue within Oct and Nov 2021. Only 4,500 miles on car. If it is having these electric issues already what is in store for this car in the future? My husband has a video on YouTube of voice activated assist issue so far 2 other people are saying their cars are having the same issue.
Brakes grind, usually after sitting overnight. It has happened on multiple occasions.
Higher-selling and older vehicles accumulate more reports. Counts are not failure rates and are not directly comparable between vehicles that sold in very different numbers.
Categories with enough reports to have a page of their own
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