Dorman - First Stop Brake Master Cylinder M80903
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Dorman - First Stop Brake Master Cylinder M80903
Dorman - First Stop Brake Master Cylinder M80903 - view 2
Dorman - First Stop Brake Master Cylinder M80903 - view 3
Dorman - First Stop Brake Master Cylinder M80903 - view 4

Dorman - First Stop Brake Master Cylinder P/N:M80903

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$67.99
MPN: M80903
Item Package Quantity: 1
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Dorman - First Stop Brake Master Cylinder P/N:M80903
Dorman - First Stop Brake Master Cylinder P/N:M80903
$67.99

Turn brake pedal effort into hydraulic pressure for your brakes with the Dorman First Stop Brake Master Cylinder M80903. This new, cast iron unit is built to match the design, function and performance of the original master cylinder. It fits many vehicles, among them the 1977-1979 Ford LTD II, 1975-1979 Ford Ranchero and 1973-1979 Ford Thunderbird, each with all engines. See the Buyer's Guide tab for the full list.

  • Precise replacement: The cylinder housing is made 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: Built to meet rigorous SAE International standards.

Specifications: 1 in. bore diameter · 2 outlets · 1/2-20 secondary outlet thread · reservoir included · sensor not included · mounting hardware not included · country of origin: China.

The master cylinder converts the force applied to the brake pedal into hydraulic pressure and sends it through the brake lines. Signs it may need replacing include a soft or sinking brake pedal, brake fluid leaking around the unit, or a lit brake warning light. Diagnose the cause before replacing any part. Mounting hardware is not included, so consult the vehicle service information for the correct fasteners and whether they may be reused. Bleed the brake system after installation.

Interchange: 783-34015 · 83-34015 · 100-2084 · 13-1525 · 10-1525 · 130.61015 · 131.61015 · 355-56002
78334015 · 8334015 · 1002084 · 131525 · 101525 · 13061015 · 13161015 · 35556002 · 18M30 · M900160 · M81015 · 11525 · MC80903 · D30Z2140A · D3AZ2140A · D60Z2140A · D6AZ2140A · 2622523 · 80903 · M1525 · M1603 · NM1525 · NM1603 · MC36397 · F80903

This part cross-references / interchanges with the following part numbers:

18M30, 783-34015, 83-34015, M900160, 100-2084, M81015, 11525, 13-1525, 10-1525, 130.61015, 131.61015, MC80903, 355-56002, D30Z2140A, D3AZ2140A, D60Z2140A, D6AZ2140A, 2622523, 80903, M1525, M1603, NM1525, NM1603, MC36397, F80903

Frequently Asked Questions

Is this the right 1973-1979 Ford Thunderbird master cylinder?

Dorman M80903 is listed as a direct-fit replacement for the 1973-1979 Ford Thunderbird with all engines. Check the Buyer's Guide tab to confirm your exact vehicle.

What does a brake master cylinder do?

It converts the force you apply to the brake pedal into hydraulic pressure. It then sends brake fluid through its outlets to the brake lines.

What comes in the box?

The package contains the master cylinder, and the reservoir is included. Mounting hardware and a sensor are not included.

What are the key specifications of M80903?

It has a cast iron housing, a 1 in. bore diameter, two outlets and a 1/2-20 secondary outlet thread. Its rubber components use an EPDM compound that resists glycol-based brake fluid.

What are signs a master cylinder may need replacing?

Common signs include a soft or sinking brake pedal, brake fluid leaking around the unit, or a lit brake warning light. Diagnose the cause first, and bleed the brakes after installation.

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