Five problems related to brake master cylinder have been reported for the 2015 Chevrolet Tahoe. The most recently reported issues are listed below. Please also check out the statistics and reliability analysis of the 2015 Chevrolet Tahoe based on all problems reported for the 2015 Tahoe.
Brake vacuum pump loses pressure when brakes pressed repetitively. While in traffic I rear ended another motorist due to brake pressure loss. Causing damage to both vehicles. No injuries due to low speed but even at high speeds brake pressure is lost, if the brake pedal is depressed repeatedly you lose all brake assist. Vehicle was brought in for recall regarding abs software update but brakes still feel horrible. TSB was issued to vehicles under 72000 but only began this year. Current TSB does not cover my vehicle. I contact the gm regarding this issue and they told me that they will not cover my vehicle one make exceptions. This needs to be a full recall of the vaccum pump, vacuum line and master cylinder like stated in the TSB. Someone can die from this issue if going down hill at speed.
Brakes failed while backing out of driveway. Brakes were hard and would not stop vehicle. Chevrolet's service bulletin indicated the vacuum pump failure will cause the master cylinder and another line to be considered "contaminated" causing them to need to be replaced. Clearly upon further investigation this is a wide spread problem.
Inadequate braking for the vehicle. My wife was traveling down a city street and could not stop the vehicle causing her to pull over for fear of her safety. The vehicle has 75000 miles on it and is out of the 60,000 mile bumper to bumper warranty. My wife all most wrecked because the brake pedal was hard and caused the vehicle to become difficult to stop. Chevy would not pay for diagnostic fee even though this is a known issue. Very unsafe to operate. Should be a full blown recall to go along with the technician service bulletin that was issued regarding the vacuum pump booster and master cylinder and other braking system components. $1400 repair estimate if the dealership follows the TSB recommendation on repair. Chevy does not care about customer safety. Unacceptable!!!.
November 2017: intermittent brake failure as low speeds (idle) when engine is hot. Generally occurs, when pulling into parking spots, backing-up, and slowly approaching stop light or stop sign. Brake pedal to floor, pedal pulses. Gm repair with new master cylinder. Said brake fluid was by-passing the piston. May 2018: intermittent brake failure as low speeds (idle) when engine is hot. This time issue started when towing a RV. Issue remained after towing ceased. Gm said test drove and stated nothing is wrong with brake system. Bring back another day to test drive if you can get issue to occur. I agree, when I retrieved the vehicle from gm, the brakes worked .
While reversing in slow speeds intermittently in forward motion, the brake pedal becomes very hard and will not stop the vehicle. The brake pedal has to be depressed very hard and there is a vibrating motion. The master cylinder has already been replaced by the dealership at an expense of nearly $600, but the issue persists.