Turn pedal effort into hydraulic brake pressure with the Dorman First Stop Brake Master Cylinder M630034, a new unit precision-engineered to match the design, function and performance of the original master cylinder. It is listed for several models, among them the 2000-2005 Chevrolet Blazer, 2000-2005 GMC Jimmy and 2000-2004 Chevrolet S10. See the "Vehicles it fits" section for the full list.
- Precise replacement: the aluminum 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 for resistance to glycol-based brake fluid.
- 100% new: made entirely from new materials, with quality and safety in mind.
- Strict specifications: built to meet rigorous SAE International standards.
Specifications: 1 in bore diameter · two outlets · 1/2-20 rearward and secondary outlet threads · reservoir included · sensor included · mounting hardware not included. Country of origin: China.
A master cylinder that leaks, lets the pedal feel soft or sink, or keeps losing fluid may need replacing. If a failed master cylinder is the cause, this unit replaces it. Diagnose the brake system before ordering, and bleed the brakes as directed by the vehicle service information after installation. Consult that service information for the correct fasteners and whether they may be reused.
Interchange: 174-780 · 83-44039 · 100-2632 · M-86039 · 13-2958 · 10-2958 · 130.66043 · 131.66043 · 355-47170
174780 · 8344039 · 1002632 · M86039 · 132958 · 102958 · 13066043 · 13166043 · 35547170 · 18M973 · M901146 · 13546 · MC500160 · 18042802 · 18060793 · NM3068 · NM3097 · MC390571 · F139958 · MC139958
This part cross-references / interchanges with the following part numbers:
174-780, 18M973, 83-44039, M901146, 100-2632, M-86039, 13546, 13-2958, 10-2958, 130.66043, 131.66043, MC500160, 355-47170, 18042802, 18060793, NM3068, NM3097, MC390571, F139958, MC139958
Frequently Asked Questions
Will this S10 master cylinder fit my 2000-2004 Chevrolet S10?
M630034 is listed for the 2000-2004 Chevrolet S10, the 2000-2005 Chevrolet Blazer and the 2000-2005 GMC Jimmy. Check the "Vehicles it fits" section to confirm your vehicle.
What does a brake master cylinder do?
It converts force from the brake pedal into hydraulic pressure and sends brake fluid through its outlets to the brakes. This unit has two outlets and a 1 in bore.
What comes in the box?
The package contains the master cylinder, with the reservoir and sensor included. Mounting hardware is not included.
What is the housing made of?
The cylinder housing is aluminum, and its rubber components use an EPDM compound for resistance to glycol-based brake fluid.
What are signs a master cylinder may need replacing?
Common signs include a soft or sinking brake pedal, fluid leaking around the unit, or a fluid level that keeps dropping. Diagnose the brake system first, since other parts can cause these symptoms.
