Dorman W45873-BX is a rear drum brake wheel cylinder for many 1964-1996 General Motors rear drum brake applications, built to replace a worn or leaking original cylinder and help restore hydraulic pressure at the shoes. Its direct-replacement design, cast iron body, EPDM rubber cups and boots, and tested bore surface make it a practical choice for brake service on classic and fleet GM platforms including Chevrolet Camaro, Chevelle, Nova, Caprice, Impala, GMC Safari, Buick Skylark, Oldsmobile Cutlass, and Pontiac Firebird.

Dorman W45873-BX Technical Specifications:

• Direct-replacement rear drum brake wheel cylinder is engineered to match the fit, function, and performance of the original unit on verified GM applications.
• Durable cast iron construction is suited for drum brake service where the cylinder body must handle hydraulic pressure and undercar exposure.
• 0.875 in. inside bore diameter provides the specified piston bore size for the listed rear brake applications.
• 3/8-24 inlet thread matches the documented brake line connection size for this wheel cylinder.
• Surface-tested wheel cylinder bores help provide a proper sealing surface for the pressure cups.
• EPDM rubber cups and boots are used to resist brake system exposure and help maintain dependable sealing performance.
• Included bleeder screw supports normal brake bleeding during installation and service.

Includes:

• Rear drum brake wheel cylinder
• Bleeder screw

A rear wheel cylinder is commonly replaced when drum brakes show fluid leakage, uneven shoe actuation, or a soft pedal caused by hydraulic loss. Inspect brake shoes, drums, hardware, and brake lines during service, and bleed the brake system after installation.

Designed for verified fitment across many GM cars and vans from the 1964-1996 model years, including applications under Buick, Chevrolet, GMC, Oldsmobile, and Pontiac. Confirm vehicle, year, brake configuration, and position before installation; disputed applications such as Chevrolet G20 Van, Chevrolet G30 Van, and Oldsmobile Cutlass Salon were not included in the verified fitment set.