Turn pedal effort into hydraulic pressure for your brakes with the Dorman First Stop Brake Master Cylinder M39651, a new replacement unit that comes with its reservoir. It fits several Chevrolet and GMC models, among them the 1988-1991 Chevrolet C1500, 1988-1991 Chevrolet K1500 and 1988-1991 GMC C1500, all engines. It is a direct-fit replacement for the listed applications; see the "Vehicles it fits" section for the full list.
Dorman precision-engineers this master cylinder to match the design, function and performance of the original unit on the listed applications. It is built from new, high-quality materials.
- Precise replacement: the aluminum cylinder housing is built to match the 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, with quality and safety in mind.
- Strict specifications: made to meet rigorous SAE International standards.
Specifications: 1 in bore diameter · two outlets · 1/2-20 rearward outlet size · reservoir included · sensor not included · mounting hardware not included. Country of origin: China.
A master cylinder that leaks or no longer holds pressure internally can cause a soft or sinking brake pedal, fluid loss at the unit, or a falling reservoir level. If the master cylinder is the cause, this unit replaces it. Diagnose the brake system first. Consult the vehicle service information for the correct fasteners, whether they may be reused, and the bleeding procedure.
Interchange: 174-667 · 783-44020 · 83-44020 · 100-2601 · M-86020 · 13-2351 · 10-2351 · 130.66020 · 131.66020 · 355-47151
18M1743 · 18M365 · M900571 · 12218 · MC116626 · 18013976 · 18060085 · NM2218 · MC39651 · F116626 · 174667 · 78344020 · 8344020 · 1002601 · M86020 · 132351 · 102351 · 13066020 · 13166020 · 35547151
This part cross-references / interchanges with the following part numbers:
174-667, 18M1743, 18M365, 783-44020, 83-44020, M900571, 100-2601, M-86020, 12218, 13-2351, 10-2351, 130.66020, 131.66020, MC116626, 355-47151, 18013976, 18060085, NM2218, MC39651, F116626
Frequently Asked Questions
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 brakes at the wheels.
Is this the right K1500 master cylinder for my 1988-1991 Chevrolet K1500?
Yes. It is listed as a direct-fit replacement for the 1988-1991 Chevrolet K1500 with all engines. See the "Vehicles it fits" section for every listed vehicle.
What comes in the box?
You get one master cylinder with its reservoir. A sensor and mounting hardware are not included.
What are the key specs of Dorman M39651?
It has a 1 in bore diameter, two outlets and a 1/2-20 rearward outlet size. The housing is aluminum, and the EPDM rubber components resist glycol-based brake fluid.
What are signs a master cylinder may need replacing?
A soft or sinking pedal, fluid leaking at the unit or a falling reservoir level may be signs, though other brake faults can cause them too. Diagnose the system before replacing parts.
