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

Problem Data
RepairPal Verified
Average mileage: 93,445 (35,000–160,000)
6 model years affected: 2007, 2008, 2009, 2010, more2011, 2012
62 people reported this problem
Viewing 1 - 20 of 32 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!
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.
Internal brake fluid leak. Master cylinder and brake booster to be replaced at a very high price!
Brake fluid leaking toMaster cylinder
Alarms stabilitrak off & service brake system
"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
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...
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?
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
Master cylinder leaking into brake booster and both need to be replaced.
Fluid leaking into Brake Booster from Master Cylider
2007 Saturn Outlook (but similar enough). I took it to the dealer to replace the Transmission Control Module... During vehicle checkup, it was discovered that the master cylinder is leaking into the brake booster. I will replace both items myself ( unless GM finally makes this a recall issue!)
Brake booster pressure sensor!
Two lights came on, the light that shows the road (I don't know if its called a road tracker or something) and brake light came on. I had to get it fixed, it cost me $812.00