Send pedal effort to every wheel as hydraulic pressure with the Dorman First Stop Brake Master Cylinder M39637, a new Mustang master cylinder that is a direct-fit replacement for the 1987-1993 Ford Mustang, 1987-1988 Ford Thunderbird and 1987-1988 Mercury Cougar (all engines). Dorman precision-engineers this unit to mirror the original master cylinder's design, function and performance on these applications, using new, high-quality materials for a safe, durable replacement.
- Precise replacement: the aluminum cylinder housing is built to match the material of the original part, for similar performance.
- Durable design: every rubber component is 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.
Specifications: three outlets; rearward outlet M10 x 1.0; secondary outlet thread M12 x 1.0; primary outlet thread pitch 1 mm. The reservoir and a sensor are included. Mounting hardware is not included, so consult the vehicle service information for the correct fasteners and whether they may be reused. Country of origin: China.
A soft or sinking pedal, fluid leaking at the master cylinder or a steadily dropping fluid level are signs this part may need replacing. Diagnose the brake system first, then install and bleed the brakes following the vehicle service procedure. See the "Vehicles it fits" section for full fitment details.
Interchange: 783-34001 · 83-34001 · 100-2067 · M-81001 · 13-4005 · 10-4005 · 130.61001 · 131.61001 · 355-54007
78334001 · 8334001 · 1002067 · M81001 · 134005 · 104005 · 13061001 · 13161001 · 35554007 · 18M355 · M900561 · 12196 · MC117583 · E7SZ2140A · E9ZZ2140A · F0ZZ2140A · 117583 · M2196 · NM2196 · MC39637 · F117583
This part cross-references / interchanges with the following part numbers:
18M355, 783-34001, 83-34001, M900561, 100-2067, M-81001, 12196, 13-4005, 10-4005, 130.61001, 131.61001, MC117583, 355-54007, E7SZ2140A, E9ZZ2140A, F0ZZ2140A, 117583, M2196, NM2196, MC39637, F117583
Frequently Asked Questions
Is the Dorman M39637 a Thunderbird master cylinder for the 1987-1988 Ford Thunderbird?
Yes. It is listed for the 1987-1988 Ford Thunderbird with all engines, and it also fits the 1987-1993 Ford Mustang and the 1987-1988 Mercury Cougar.
What does a brake master cylinder do?
It converts the force on the brake pedal into hydraulic pressure and sends brake fluid through the lines to the wheel brakes. This unit has three outlets.
What comes in the box?
The master cylinder with its reservoir and a sensor. Mounting hardware is not included, so consult the vehicle service information for the correct fasteners and whether they may be reused.
What are the outlet thread sizes?
The rearward outlet is M10 x 1.0, the secondary outlet thread is M12 x 1.0, and the primary outlet thread pitch is 1 mm.
What are signs a master cylinder may need replacing?
A soft or sinking brake pedal, fluid leaking at the master cylinder or a dropping fluid level can be signs. Diagnose the brake system first, as other parts can cause these symptoms.
