Brakes completely failed. Replaced brakes on all 4 wheels, but to no avail. Then replaced the master cylinder and still no brakes. My fence pole and mailbox stopped my vehicle.

- Albuquerque, NM, USA

When I first got the truck the brakes operated perfectly fine after about three days the brakes on the front of the truck would lock up while I was driving and would not release. After two sets of calipers two sets of brake pads a set of rotors a two weeks go by with the mechanic trying to figure out what is wrong with this truck. They then replace the brake master cylinder, there was no improvement. Turns out to be the brake booster had failed along with the hydraulic ABS control unit. There were no warning lights on whatsoever the whole entire time the brakes were locked up the ABS light didn't come on until the brake booster was replaced indicating that the ABS control unit was also bad. Now I am experiencing a ticking coming from the engine. The ticking occurs at idle end as the throttle is being activated. However the local dealership has refused to give me any information as of why it could be making this ticking noise or is just unwilling to say anything.

- Paw Paw, MI, USA

I pushed on the brakes when slowly pulling into a parking spot and the brakes got squishy and barely stopped before I hit another parked car. This happened a few times before I got the vehicle home. Then a message popped up that said "service brake assist system". I took the truck in and they said they would need to replace the vacuum pump and 2 belts.

- Collinsville, OK, USA

Brake assist warning light came on with hard brake pedal at low speed braking. Does not happen ofter. Brought to dealer and had tested with no trouble found. Dealer said no recalls or service bulletins on issue.

- Metairie, LA, USA

Brakes not working. Had to replace the vacuum pump belt, brake booster vacuum pump, and ac belt. Cost $573.86. Vehicle only has 40K miles. Very dangerous, vehicle would not stop when applying brakes

- Berkley, MA, USA

At low speeds breaking becomes extremely difficult leading to longer stopping distance.

- Northglenn, CO, USA

Brakes fade at low speeds, vehicle continues to travel while the brakes are applied. Hard brake pedal pressure must be applied to stop.

- Wildomar, CA, USA

Brake pedal or that increased effort is needed to depress the brake pedal. Also, in some cases a tick or ticking noise may be heard, which may sound like an exhaust manifold leak.

- Spring, TX, USA

I was on a major highway traveling when the traffice became stop and go. As I was traveling in heavy traffic for about 5 minutes, my brake became stiff and would not allow me to stop as normal. I was able to stop just short of rear-ending the vehicle in front of me, however it was merely by inches. Considerations : I was on a slight decline and my vehicle has start assist where the brake pedal remains stiff when in effect, it felt like this activated. I continued to increase pressure through which I thought I heard the ABS activate and the vehicle stopped.

- Littleton, CO, USA

At low speeds break pedal will not depress and I have a hard time stopping the truck. I almost hit a car yesterday and after doing some research found that the vacuum pump failure is a known problem. This is extremely scary and dangerous. Someone could easily hit a pedestrian. My truck has less than 50,000 miles, which seems to be the average for this problem.

- Elk Horn, KY, USA

The contact owns a 2015 GMC Sierra 1500. The contact stated that when the brake pedal was applied, the vehicle failed to respond. The contact had to apply force to the brake pedal to stop the vehicle. Laura Buick GMC (903 N bluff rd, collinsville, il 62234, (618) 344-0121) diagnosed that the brake vacuum pump may need to be replaced. The vehicle was not repaired. The contact was uncertain if the failure was related to NHTSA campaign number: 14V339000 (steering, service brakes, hydraulic). The manufacturer was notified of the failure. The VIN and failure mileage were not available.

- Portageville, MO, USA

Brake pedal goes soft and can hit the floor on occasion. Mostly happens with in reverse. 40K miles. Also transmission shifts are erratic. RPM can shoot up between shifts.

- Saint Charles, IL, USA

Several times at low speed maneuvering the brake pedal became hard, required increased effort to depress, and braking distances were increased. Occurs randomly and without warning. No accidents yet, but several close calls. Vehicle has only 44,000 miles.

- Ottoville, OH, USA

At slow speeds the brake assist does not work. Requires much more effort to stop vehicle. Seems related to faulty vacuum pump as mentioned by ohters on internet forums.

- Gloucester, MA, USA

When applying brakes after first push the pedal gets hard and doesn't stop hardly. Does it either going forward or reverse. Has happened numerous times since truck was bought new.

- Muskegon, MI, USA

Loss of power brakes when creeping and applying brakes several times in a short time. Tested and changed vacuum pump.

- Menasha, WI, USA

The contact owns a 2015 GMC Sierra 1500. While driving at low speeds or when the gear selector was in reverse, the brake pedal traveled to the floorboard. The contact mentioned that the failure occurred periodically. The vehicle was taken to everett Buick GMC (21115 I-30 frontage rd, bryant, ar 72022, (501) 303-4393) to be diagnosed, but no failure was found. The dealer stated that the brakes were "perfect". the vehicle was not repaired. The manufacturer was made aware of the failure. The VIN was not provided. The failure mileage was 45,000.

- Sherwood, AR, USA

I was driving down a hill at about 15 miles an hour and when I went to press the brake pedal I heard a noise and the brake pedal went to the floor and truck would not stop. I had to swerve off the road to avoid a collision. After, the brake pressure returned while driving, but when stopped it would lose pedal feel and go back to the floor. After reading articles it was obvious the vacuum pump was failing. I limped the truck home and took it to the dealership and am waiting to hear back.

- Lancaster, CA, USA

There is a known brake problem caused by faulty vacuum pump. With the vacuum pump failing there will be loss of assisted braking. Some people have noted requiring 2 feet to stomp on the brakes to stop the truck. The dangerous braking problem seems to happen during low speeds. Some members on the forums have mentioned getting into accidents. GMC does not cover the vacuum pump under their warranty which is ridiculous. I have listed some forum threads as proof of not just me having this issue. Https://www.silveradosierra.com/ecotec3-5-3L-V8/brake-booster-vacuum-pump-failure-T686609.html https://www.silveradosierra.com/brakes/rock-hard-brake-pedal-2014-low-speed-T595097.html https://www.GM-trucks.com/forums/topic/204871-vacuum-pump-going-out/ https://fox6now.com/2018/11/23/GM-under-investigation-for-faulty-brake-vacuum-pumps/ even the government is investigating.

- San Francisco, CA, USA

It started happening a week or so ago where when in reverse or after switching from reverse to drive and trying to brake the pedal wouldn't compress, it was as if they were locking up on me. I would have to put most of my body weight on the pedal to even get the truck to stop, to the point where I almost ran into my neighbors car backing out of the driveway. It seemed to mainly happen at slower speeds, in both drive and reverse as it happened on more than one occurrence. Luckily I decided to take it to the GMC dealer before anything serious happened, but this is a huge safety concern and I feel it needs to be addressed. The dealer also knew exactly what the issue was before I could give them any information, so it seems like this is a common problem. They replaced my vacuum pump and we will see if that fixes the problem.

- San Angelo, TX, USA