Keep brake pedal effort turning into steady hydraulic pressure with the Dorman First Stop Brake Master Cylinder M98953, a new cast-iron unit with the reservoir included. It fits many vehicles, among them the 1975-1983 Chevrolet C30, 1977-1983 Chevrolet K30 and 1975-1983 Chevrolet P30 (all engines), and the "Vehicles it fits" section lists every application. Dorman engineered it to replicate the original master cylinder's design, function and performance on the listed applications, and built it from new, high-quality materials for a durable replacement.
- Precise replacement: The cast-iron cylinder housing is built to match the casting material of the original part and is intended to deliver similar performance.
- Durable design: Every rubber component uses a high-quality EPDM compound that resists glycol-based brake fluid.
- 100% new: Made entirely of new materials for quality and safety.
- Strict specifications: Made to meet rigorous SAE International standards.
Specifications: 1.313 in bore diameter, two outlets and a 1/2-20 rearward outlet size. The reservoir is included. A sensor and mounting hardware are not included, so consult the vehicle service information for the correct fasteners. Country of origin: China.
If a leaking or internally worn master cylinder is the cause of a soft or sinking brake pedal, this unit replaces it. Diagnose the brake system before replacing parts, and bleed the brakes as directed by the service procedure after installation.
Interchange: 783-44005 · 83-44005 · 100-2579 · M-86005 · 13-1584 · 10-1584 · 130.66005 · 131.66005 · 355-47140
78344005 · 8344005 · 1002579 · M86005 · 131584 · 101584 · 13066005 · 13166005 · 35547140 · 18M71 · M900232 · 11584 · MC98953 · 14008238 · 14036115 · 6260725 · 98953 · M1584 · NM1584 · MC39017 · F86510 · F98953 · MC86510
This part cross-references / interchanges with the following part numbers:
18M71, 783-44005, 83-44005, M900232, 100-2579, M-86005, 11584, 13-1584, 10-1584, 130.66005, 131.66005, MC98953, 355-47140, 14008238, 14036115, 6260725, 98953, M1584, NM1584, MC39017, F86510, F98953, MC86510
Frequently Asked Questions
Will this P30 master cylinder fit my 1975-1983 Chevrolet P30?
Yes. Dorman M98953 is a direct-fit replacement listed for the 1975-1983 Chevrolet P30 with all engines. The "Vehicles it fits" section shows every listed application.
Does it fit the 1975-1983 Chevrolet C30 and the 1977-1983 Chevrolet K30?
It is listed for the 1975-1983 Chevrolet C30 and the 1977-1983 Chevrolet K30, all engines. The "Vehicles it fits" section lists the other applications.
Does the master cylinder come with a reservoir?
Yes, the reservoir is included. A sensor and mounting hardware are not included, so consult the vehicle service information for the correct fasteners and whether they may be reused.
What are the specifications of M98953?
It has a cast-iron cylinder housing, a 1.313 in bore diameter, two outlets and a 1/2-20 rearward outlet size, and it is made to meet SAE International standards.
What are signs a brake master cylinder may need replacing?
Signs include a soft or sinking brake pedal, fluid leaking around the master cylinder or a dropping fluid level. Diagnose the brake system to confirm the cause before replacing parts.
