Dorman 42070 Brake Master Cylinder Reservoir Cap Gasket

Brake Master Cylinder Reservoir Cap Gasket for OE Fit

This Dorman brake master cylinder reservoir cap gasket is built to match the original gasket’s fit and function on specified vehicles. Made from rubber, it helps maintain a proper seal at the reservoir cap for dependable brake system performance.

• Rubber construction for sealing performance and durability
• Direct-fit replacement for the original brake master cylinder reservoir cap gasket
• Designed for specified Buick, Chevrolet, Oldsmobile, Pontiac, and Cadillac applications
• Cross-references Dorman 420704 and 5470861 for the same application
• Part number 42070 for brake master cylinder reservoir service

Detailed Product Overview

Dorman 42070 is a brake master cylinder reservoir cap gasket engineered to match the fit and function of the factory gasket on listed vehicles. It is used in brake master cylinder reservoir sealing applications where a stable rubber gasket is needed to help maintain the cap-to-reservoir seal. This part number 42070 is a practical OE-style replacement for service work on classic GM platforms, including Chevrolet Chevette, Pontiac Sunbird, Buick Skylark, and related models.

Compatible With 1968-1987 Buick, Chevrolet, Cadillac, Oldsmobile, and Pontiac vehicles listed in the fitment data, including applications such as 1978-1987 Chevrolet Chevette, 1971-1974 Chevrolet Nova, 1968-1972 Pontiac GTO, and 1968 Cadillac DeVille. The fitment also includes specific configurations such as Moraine brakes, front drum brakes, and cast iron original cylinder applications where noted.

What This Part Helps Address

• Brake fluid seepage at the master cylinder reservoir cap
• Loss of sealing at the reservoir opening
• Degraded or hardened original rubber gasket material
• Service needs on aging brake master cylinder reservoirs
• Replacement during brake system maintenance on classic GM vehicles

Installation Notes and Tips

Inspect the reservoir cap and sealing surface before installation. Clean the mating surfaces thoroughly and confirm the gasket seats evenly in the cap groove or reservoir interface. Verify the vehicle’s brake system configuration against the listed fitment notes, especially where Moraine brakes, front drum brakes, or cast iron original cylinder references are specified.

Quality Assurance

Dorman designs this gasket to match original fit and function on specified vehicles and to provide durable, reliable service in brake system applications. Part number 42070 is supported by listed interchange references for the same application.