Three vehicle owners from Pennsylvania, New York, and Missouri have refiled a class action lawsuit against General Motors, alleging defective brake master cylinder assemblies across five 2025 model year vehicles. The amended complaint adds a third plaintiff and a third state to a case originally dismissed in early 2026.
Highlights
- Three plaintiffs allege premature internal seal failure in brake master cylinders causes sudden hydraulic pressure loss across five 2025 GM models.
- The refiled lawsuit expands geographic scope from two states to three, adding Missouri to the original New York and Pennsylvania claims.
- GM previously succeeded in having the original two-plaintiff version of the case dismissed after arguing the components were replaced at no cost.
- A December 2024 GM service update acknowledged the master cylinder defect in 2024 Traverse and 2025 Enclave models, but the lawsuit alleges the same components are used in all five affected vehicles.
Vehicles and Defect at Issue
The lawsuit covers the 2025 Chevrolet Traverse, 2025 GMC Acadia, 2025 Buick Enclave, 2025 Chevrolet Colorado, and 2025 GMC Canyon. According to the complaint, internal seals inside the brake master cylinder assemblies fail prematurely, allowing brake fluid to bypass or leak. The result is a loss of hydraulic pressure that can degrade or eliminate braking performance.
Symptoms described in the lawsuit include a hard brake pedal, a pedal that falls to the floorboard, illumination of the red brake warning light and ABS warning light, and a “Service Brake System” dashboard message.
Case History and Dismissal
The original class action was filed in October 2025 by Pennsylvania plaintiff Eric Barron and New York plaintiff Chelsey Thompson, both owners of 2025 Chevrolet Traverse SUVs. That case sought more than $5 million in damages.
GM moved to dismiss, arguing neither plaintiff suffered actual injury because both had their master cylinders replaced at no charge under warranty. A federal court agreed, finding the plaintiffs failed to demonstrate concrete harm. The judge also noted that the owners had not pursued GM’s informal dispute resolution process before filing lemon law claims.
Refiled Complaint Adds Missouri Plaintiff
The amended lawsuit now includes Simon Moeller of Missouri, who owns a 2025 GMC Acadia with the same master cylinder failure. As with the other plaintiffs, GM replaced the part at no cost. However, all three plaintiffs wrote to GM after their repairs, asserting that all five 2025 models carry the same defective component.
The claims include breach of express warranty, breach of implied warranty of merchantability, fraudulent concealment, and unjust enrichment. Barron and Thompson also invoke the Pennsylvania and New York lemon laws, respectively.
GM Service Bulletin and Prior Knowledge Allegations
A central element of the lawsuit is GM Service Update N242482170, issued in December 2024. That bulletin directed dealers to replace brake master cylinders in 2024 Chevrolet Traverse and 2025 Buick Enclave vehicles where the internal cartridge seal in the eBoost Module was missing.
GM has countered that none of the three current plaintiffs own either of the two models covered by that service update. However, the plaintiffs argue the same brake master cylinder assemblies are installed across all five named vehicles.
The lawsuit further alleges GM had knowledge of the defect months before the service update through internal testing, warranty claims, and dealership repair data. The complaint cites a higher-than-expected volume of replacement master brake cylinder assemblies ordered by GM dealerships as evidence, though no specific figures are provided.
No Recall Issued
Despite the service bulletin and multiple NHTSA complaints from owners describing brake failure incidents, GM has not issued a safety recall covering any of the five 2025 models named in the suit. Several NHTSA complaints describe extended waits for replacement parts, with some owners reporting dealership wait times of two months or more due to nationwide parts backorders.
The case, Barron, et al., v. General Motors LLC, was filed in the U.S. District Court for the Eastern District of Pennsylvania. The plaintiffs are represented by attorney Sergei Lemberg.
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