Dorman 42073 Brake Master Cylinder Reservoir Cap Gasket

Brake Master Cylinder Reservoir Cap Gasket for GM Vans

Dorman 42073 is a rubber brake master cylinder reservoir cap gasket made to match the fit and function of the original gasket on specified vehicles. It is built for dependable sealing performance in the brake master cylinder reservoir, helping maintain a proper seal at the cap.

Compatible With Chevrolet and GMC applications including Astro, Safari, G10, G20, G30, P20, P30, G1500, G2500, G3500, and P2500/P3500 models with the listed reservoir configurations. Dorman 42073 is a direct-fit service part for brake reservoir cap sealing on these GM platforms.

Key Features

• Rubber construction for sealing performance in brake reservoir service
• Matches the original gasket fit and function on specified vehicles
• Designed for front reservoir applications with vacuum power brakes where noted
• Direct replacement for brake master cylinder reservoir cap gasket service
• Cross-references OE numbers 18014183 and 18014184 for the same application

Detailed Description

This brake master cylinder reservoir cap gasket is engineered for GM brake systems that require a precise seal at the reservoir cap. The Dorman 42073 helps restore the sealing interface between the cap and master cylinder reservoir, which is important for maintaining brake fluid containment and reducing contamination exposure. It is a practical replacement for Chevrolet Astro, G10, G20, G30, P20, and P30, as well as GMC Safari, G1500, G2500, G3500, P2500, and P3500 applications listed in the fitment data.

Use Dorman 42073 when servicing the brake master cylinder reservoir on the specified Chevrolet and GMC vans and chassis models. The part number 42073 is a focused replacement for reservoir cap gasket service where the original seal has aged, hardened, or no longer seats correctly.

What It Helps Address

• Brake fluid seepage at the master cylinder reservoir cap
• Loss of sealing integrity from a worn or hardened gasket
• Contamination entering the reservoir through a compromised cap seal
• Service issues on GM brake master cylinder reservoir cap gasket applications
• Replacement needs on Chevrolet Astro, G10, G20, G30 and GMC Safari, G1500, G2500, G3500 platforms

Installation Notes and Tips

Inspect the reservoir cap and sealing surface before installation. Clean the mating surfaces thoroughly, then install the gasket so it seats evenly without twisting or pinching. Verify the application matches the vehicle’s reservoir configuration, including front reservoir and vacuum power brake notes where listed. After service, confirm the cap is fully seated and the brake fluid level is correct.

Quality Assurance

Dorman designs this gasket to match original fit and function for the specified vehicles, with a focus on durability and reliable performance in brake system service.