2015 Tahoe Brakes Fail at Low Speed

Mo Sherif · January 12, 2019

i replaced the brake pads and rotors multiple times, vacuum pump, master, booster, rear calipers, abs pump. i also bleed the brakes over 10 times. some the old pump and hold and some with the gm tool. i still can't get the brakes to work as they should. what the hell do i do next.

Tahoe02 · January 14, 2019

Maybe take it to an independent shop that specializes in brake work.

Ira1976 · January 17, 2019

I've gotten a ton of good info, troubleshooting tips, and fixes off of this site over the last few years. Any help or recommendations are greatly appreciated. Here's my issue:

I have a 2015 Tahoe with 49K miles. Over the last few days, it has developed an intermittent issue where the bakes fail to engage at low speed. I've noticed it when pulling into parking spaces and inching forward in stop and go traffic. It feels as if there is no hydraulic pressure in the system, and I can feel the ABS pulsing the pedal when it happens. I have to stand on the brakes to get them to grab. I'm fairly handy and have probably performed over 50 brake jobs in my lifetime. Here are a few of the items I've checked:

- The brake fluid is at the MAX level in the reservoir
- Removed front wheels and brake pads are at least 50%
- Bled front brake lines to ensure there were no air pockets (steady stream of fluid)

I have not had the brakes act up at speeds over 25 mph - it always seems to have good stopping power and pedal feel at road / highway speeds. Normally this would be a straight trip to the dealer, but I have little faith in my local dealerships. Took 3 of them to finally fix an engine "tapping" in my 2014 Silverado. After I was the one who noticed a broken exhaust manifold bolt by seeing the soot on the head next to the broken bolt...

I saw some of the posts below and just wanted to confirm that its 100% the brake vacuum pump ..... been there. Shortly after , around the Sam mileage(not related) , the a/c condenser will fail . Itll be blowing cold in the back row but warm up front , just giving you a heads up

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SkunKnuckles · March 9, 2019

I'm changing the vacuum pump on a 2015 chevrolet suburban right now. Same symptoms.

From GMPartsGiant, I ordered:

vacuum pump part number 12669488

gasket part number 1263901

It turned out the gasket was unnecessary because one already came with the pump.

Today I mucked about trying to get the 4 bolts out of the vacuum pump. It was a real nightmare until I finally removed the steering column, which had pretty effectively blocked access to the pump from the drivers side. Now I'm able to access the pump fairly easily, and have removed all four bolts. It was getting dark when I quit for the day.

It looks as if the wiring harness has a plastic channel that keeps it away from the belts and pulleys at the front of the vehicle, and that this channel is connected to the vacuum pump with some kind of press in connector. In the light of a new day, I'll probably use a screwdriver to try to pry the plastic connector out of the vacuum pump. Then, it'll be ready to life it out. I'm expecting tomorrow to go a lot more smoothly than today went, before I removed the steering column.

We'll see

BretAz48 · March 12, 2019

My 2015 Yukon XL does this as well. If you sit too long with your foot on the brake, then let off the brake and have to hit it again, the pedal is rock hard and the brakes work only about 20% of normal. First couple times it did this were a little scary.

GM knows about this problem, and like most problems with their products they try to cover it up.

https://www.carcomplaints.com/news/2018/gm-brake-vacuum-pump-failures-lawsuit.shtml

Ira1976 · March 12, 2019

My 2015 Yukon XL does this as well. If you sit too long with your foot on the brake, then let off the brake and have to hit it again, the pedal is rock hard and the brakes work only about 20% of normal. First couple times it did this were a little scary.

GM knows about this problem, and like most problems with their products they try to cover it up.

https://www.carcomplaints.com/news/2018/gm-brake-vacuum-pump-failures-lawsuit.shtml

If gm acknowledges every issue with these trucks , they do basically have to recall every single truck and give you a new one . I wonder if I can get my money back for my brake vac pump

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BretAz48 · March 12, 2019

Mine was intermittent. But after reading this thread I am sure it is related to my vacuum pump. I have spent $8,000 on repairs on this truck in the last 6 months. I guess I will add this to the future list.

The first time it does it, it really catches you off guard. I about shit my pants the first time it did it.