Brake booster failure due to internally leaking brake master cylinder on GMC Acadia

Problem Data
RepairPal Verified
Average mileage: 90,477 (35,000–160,000)
7 model years affected: 2007, 2008, 2009, 2010, more2011, 2012, 2015
77 people reported this problem
Viewing 1 - 20 of 37 comments
"Stabilitrak off, service brake system" with Brake warning light and skidding vehicle light both on.
I got a msg on my dash that read "stabilitrak off", then "check brakes". Took it in & they tell me the master cylinder was leaking brake fluid & it leaked right onto the brake booster (design flaw maybe?) so I had to replace both master cylinder & booster to the tune of $1100! Not too happy with it at all. Definitely won't be purchasing another GM vehicle in the future! Never had any issues with my Honda. Should've stuck with them!
Internal brake fluid leak. Master cylinder and brake booster to be replaced at a very high price!
Service brake system message, sometimes Service Stability, red brake light and TRAC OFF message.
These are sometimes the result of low brake fluid, but no obvious leaks are noted. Due to the design of the master cylinder and brake booster, the master cylinder can leak from the rear seal and collect inside the booster, leaving no drops on the ground or obvious signs.

You will need to replace the master cylinder and booster to correct.
"Stabilitrak off, brake fluid light constantly coming on, Brake warning light and skidding vehicle light both on.
After reading manual stated 1 of 2 options 1.) brake lining worn 2.) hydraulic brake leak
Well it was neither so now I have to take to dealer to see if it is I guess need to replace the master cylinder and booster to correct. This will be a difficult amount to pay. Is this normal??? Should this be a recall
service break system light comes on. dinging sound .stability off, parking break on
Brake fluid leaking toMaster cylinder
Alarms stabilitrak off & service brake system
Same scenario stabilizer light off and check brake indicator. Master cylinder leaking in tobrake booster $900 repair bill. Obviously a design issue will not buy another GMC product.
Stabilitrak off and service brakes light on and leaking under the truck. Wife backing out driveway and brakes go to the floor...
At such low mileage it is extremely disappointing to have this same problem (at the tune of $1000), which naturally started just after the warranty period expired. I am also experiencing the steering wheel noise problem($1400)and noises from worn out lower control arm bushings($800). My recommendation is either not buy a GM (government motors)vehicle or unload it before the end of the warranty period. You can also get the 2 year extended warranty for about $3500. I will never buy another GM vehicle again.
leaking internal brake master cylinder to the booster
Brake works fine sometimes, but just started failing last week. I apply the breaks and it goes all the way down but car does not stop. Need to pump brake and then it stops. It freaks me out! Diagnosis is to replace booster and master cylinder for $714 at dealership. Not fun since just replaced the transmission at 101K mi for same Acadia for $3,300. What's next?
Master cylinder leaking into brake booster and both need to be replaced.
2011 Buick Enclave. Replaced brake pads and one caliper at 86K and a few days later squeak noise in brake pedal was heard. Buick dealer diagnosed as brake master cylinder leaking into booster.
Internal brake fluid leak and master cylinder and brake booster to be repaired only had this vehicle for six months!!
Haven't noticed any apparent leaking on garage floor but after getting transmission problems fixed, which was a dealer flaw, they discovered that my master brake cylinder and brake booster needs to be replaced.
Service stability light comes on
Brakes slightly squishy. Dealer found brake fluid low, leak from rear of master cylinder into brake booster. Require all to be replaced. $900.
Brake booster went out in traffic.
Same thing here. Stabilitrak OFF warning light and Service Brake System. Took to Liberty GMC this morning and they said internal brake leakage - Master cylinder has leaked into Cylinder Booster and both need to be replaced - $900+ bill!