Replace a worn or leaking unit at the heart of the hydraulic brake system with this Dorman brake master cylinder from the First Stop line, part number M37781, which turns brake-pedal force into hydraulic pressure for the brakes. It fits many vehicles, among them the 1966 Ford F-250, 1966 Ford Bronco and 1961-1966 Ford F-100, as a direct-fit replacement for the listed applications.
Dorman precision-engineered this master cylinder to replicate the original unit's design, function and performance. It is built from new, high-quality materials for a safe, durable replacement.
- Precise replacement: The cylinder housing is constructed to match the casting material of the original part for similar performance.
- Durable design: Every rubber component uses a high-quality EPDM compound that resists glycol-based brake fluid.
- 100% new: Made entirely from new materials for quality and safety.
- Strict specifications: Made to meet rigorous SAE International standards.
Signs a master cylinder may need replacing include a soft or sinking brake pedal, fluid leaking at the cylinder, or a fluid level that drops with no leak elsewhere in the system. Diagnose the brake system before replacing parts. See the "Vehicles it fits" section for the full list of Ford and Studebaker applications and engine details.
Interchange: 83-42009 · 100-2452 · M-85009 · 13-37781 · 10-37781 · 130.65009 · 355-54135
8342009 · 1002452 · M85009 · 1337781 · 1037781 · 13065009 · 35554135 · M900065 · 11253 · MC501140 · C1TT2A032C · C1TZ2140A · C3TZ2140H · C5TZ2140A · C5TZ2140C · 5463220 · NM37781 · MC36072 · 1696852 · F106422 · F37781 · MC37781
This part cross-references / interchanges with the following part numbers:
83-42009, M900065, 100-2452, M-85009, 11253, 13-37781, 10-37781, 130.65009, MC501140, 355-54135, C1TT2A032C, C1TZ2140A, C3TZ2140H, C5TZ2140A, C5TZ2140C, 5463220, M37781, NM37781, MC36072, 1696852, F106422, F37781, MC37781
Frequently Asked Questions
What does a brake master cylinder do?
It converts force from the brake pedal into hydraulic pressure and sends brake fluid through the brake lines to the wheel brakes.
Is this the right Ford F-250 brake master cylinder for a 1966 truck?
It is listed as a direct-fit replacement for the 1966 Ford F-250, 1966 Ford Bronco and 1961-1966 Ford F-100. See the "Vehicles it fits" section for every listed vehicle.
What are the rubber components in this Dorman master cylinder made of?
All rubber components use a high-quality EPDM compound, chosen for its resistance to glycol-based brake fluid.
What are signs a brake master cylinder may need replacing?
Common signs include a soft or sinking brake pedal, fluid leaking at the cylinder, or a fluid level that drops with no other visible leak. Diagnose the brake system before replacing parts.
Does the brake system need bleeding after installation?
Follow the vehicle service information. A new master cylinder is typically bench-bled before installation, and the brake system is bled afterward to remove air.
