GM Master Cylinder Failure Class Action: Brake Defects Raise Safety and Lemon Law Concerns
What’s the Problem
A new class action lawsuit alleges that General Motors (GM) sold several 2025 model-year vehicles with dangerous master cylinder defects that can cause sudden brake failure.
According to the complaint, affected owners experienced warning messages like “Brake,” “ABS,” and “Service Brake System,” followed by a soft or sinking brake pedal, increased stopping distance, and, in some cases, complete brake loss.
The vehicles named in the lawsuit include:
2025 Chevrolet Traverse
2025 GMC Acadia
2025 Buick Enclave
2025 Chevrolet Colorado
2025 GMC Canyon
The plaintiffs allege GM knew of the problem before selling these vehicles, yet failed to issue a recall or provide timely repairs. They claim parts were backordered for months and that GM continued to represent the vehicles as safe and reliable.
Allegations
The class action, filed in the Eastern District of Pennsylvania, accuses GM of:
Concealing a known safety-critical defect in the master cylinder.
Delaying or denying warranty repairs despite repeated owner complaints.
Failing to provide adequate replacement parts or recall coverage.
Selling vehicles that were unmerchantable and worth less than represented.
The plaintiffs argue that the defect violates GM’s New Vehicle Limited Warranty and various state consumer protection statutes. The proposed class covers New York and Pennsylvania purchasers and lessees.
Recall / TSB Status
As of the filing date, GM has not issued a formal recall for the master cylinder defect. While some repairs have been performed under warranty, the lawsuit alleges that these were inconsistent and that GM’s dealers often lacked parts to complete the work promptly.
No Technical Service Bulletin (TSB) has yet been published publicly addressing the root cause of the master cylinder failures, leaving many owners uncertain about repair timelines or long-term safety.
Symptoms Reported by Owners
Owners have described multiple warning signs that may indicate a failing master cylinder, including:
“Brake” or “ABS” warning lights appearing suddenly
Brake pedal that sinks to the floor or loses pressure
Increased stopping distance or delayed braking response
Hard or inconsistent pedal feel
Brake fluid loss without visible leakage
Because the master cylinder directly controls brake pressure, loss of function can lead to catastrophic safety risks, especially at highway speeds.
How to Proceed
Document Issues: Keep detailed records of all repair attempts and communications with the dealership or GM. Make sure your concerns are accurately written on every work order when you drop off the vehicle.
Reasonable Number of Repair Attempts: Under California’s lemon law, if the same safety defect persists after multiple repair attempts—or if the vehicle is out of service for more than 30 days—you may qualify for relief under the Song-Beverly Consumer Warranty Act.
Monitor Symptoms: If your brake pedal softens, sinks, or warning lights appear, stop driving and contact the dealership immediately. Continued operation could pose a severe safety hazard.
Talk to a Lemon Law Attorney, like Valero Law: If your GM vehicle continues to exhibit brake or hydraulic issues despite repairs, you may be entitled to a buyback, replacement, or cash settlement under California’s lemon law.
Call Valero Law
Protect Your Rights Under California Lemon Law
If you are a GM owner dealing with brake or master cylinder defects, you may be entitled to compensation under California’s Lemon Law.
Remedies can include:
A full repurchase of your defective GM vehicle
A replacement vehicle of equal value
Or substantial cash compensation for loss of use and diminished value
If your Chevrolet, GMC, or Buick has experienced brake failure, warning lights, or repeated service visits, call Valero Law, APC at (424) 299-4447 or complete a free Lemon Law case evaluation below.