Keep pedal effort turning into hydraulic pressure at every wheel with the Dorman First Stop Brake Master Cylinder M99031. It is a direct-fit replacement for many vehicles with all engines, among them the 1978-1980 Chevrolet Malibu, 1978-1980 Chevrolet El Camino and 1978-1980 Chevrolet Monte Carlo; see the "Vehicles it fits" section for the full list.
Precision-engineered to mirror the original master cylinder's design, function and performance on the listed applications, this unit is built from new, high-quality materials.
- Precise replacement: the cast iron cylinder housing is constructed to match the casting material of the original part and is intended to deliver similar performance.
- Durable design: every rubber component is made from 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: 0.938 in. bore diameter, 2 outlets, 1/2-20 rearward outlet size. A reservoir is included; a sensor and mounting hardware are not included. Consult the vehicle service information for the correct fasteners and whether they may be reused. Quantity per application: 1. Country of origin: China.
Signs this part may need replacing: a spongy or sinking brake pedal, fluid seeping from the cylinder, or a brake fluid level that keeps dropping. Diagnose the cause before replacing, since other brake components can produce similar symptoms.
Interchange: 783-36003 · 83-36003 · 83-50003 · 100-2208 · M-82003 · 13-1738 · 10-1738 · 130.62003 · 131.62003 · 355-47024
78336003 · 8336003 · 8350003 · 1002208 · M82003 · 131738 · 101738 · 13062003 · 13162003 · 35547024 · 18M70 · M900231 · 11738 · MC101253 · 18003755 · 18005259 · 18006633 · 18009881 · 101253 · M1738 · NM1738 · MC39016 · F101253 · F99031 · MC99031
This part cross-references / interchanges with the following part numbers:
18M70, 783-36003, 83-36003, 83-50003, M900231, 100-2208, M-82003, 11738, 13-1738, 10-1738, 130.62003, 131.62003, MC101253, 355-47024, 18003755, 18005259, 18006633, 18009881, 101253, M1738, NM1738, MC39016, F101253, F99031, MC99031
Frequently Asked Questions
Does the Dorman M99031 come with a reservoir?
Yes, a reservoir is included. A sensor and mounting hardware are not included, so consult your vehicle's service information for the correct fasteners and whether the originals may be reused.
Which vehicles does this master cylinder fit?
It fits many vehicles, among them the 1978-1980 Chevrolet Malibu, 1978-1980 Chevrolet El Camino and 1978-1980 Chevrolet Monte Carlo. See the "Vehicles it fits" section for the full list.
What is the housing made of?
The cylinder housing is cast iron, constructed to match the casting material of the original part. Its rubber components use an EPDM compound for resistance to glycol-based brake fluid.
What are signs a brake master cylinder may need replacing?
A spongy or sinking brake pedal, fluid seeping from the cylinder, or a steadily dropping fluid level can be signs of a worn master cylinder. Diagnose first, as other brake parts can cause similar symptoms.
What are the bore and outlet specifications?
The M99031 has a 0.938 in. bore diameter, 2 outlets and a 1/2-20 rearward outlet size, and it is made to meet SAE International standards.
