Turn brake-pedal effort into the hydraulic pressure that operates both brake circuits with the Dorman - First Stop Brake Master Cylinder (M630454). It's a direct-fit replacement for the 2007-2008 Chevrolet Silverado 2500 HD and 3500 HD, GMC Sierra 2500 HD and 3500 HD, Chevrolet Express 2500/3500, GMC Savana 2500/3500, Chevrolet Suburban 2500, and GMC Yukon XL 2500 (all engines) — see the Buyer's Guide tab for the full list. It's engineered to match the original master cylinder's design, function, and performance on the listed applications.
- 100% new, not remanufactured: built entirely from new materials, with an aluminum housing constructed to match the casting material of the original part for similar performance.
- Glycol-fluid-ready seals: all rubber components use a high-quality EPDM compound for resistance to glycol-based brake fluid.
- Built to spec: two outlets with M12 x 1.0 outlet threads (1 mm pitch) and a 36.9 mm bore; made to meet rigorous SAE International standards.
- What's included: the reservoir and sensor are included; mounting hardware is not included — consult the vehicle service information for the correct fasteners and whether they may be reused.
Signs the original master cylinder may need replacing include a brake pedal that slowly sinks toward the floor, a spongy pedal, or fluid loss at the cylinder. If a failed master cylinder is the cause, this unit replaces it; diagnose the cause before replacing. Country of origin: China.
Interchange: 100-2647 · 1002647 · 13-3331 · 133331 · 10-3331 · 103331 · 10-4305 · 104305 · 130.66057 · 13066057 · 355-47183 · 35547183 · 15106442 · 15146189 · 19209189 · NM4183 · MC391082 · F143037 · MC143037. Manufacturer part number M630454.
This part cross-references / interchanges with the following part numbers:
Frequently Asked Questions
What does a brake master cylinder do?
It converts the force from your brake pedal into hydraulic pressure, pushing brake fluid out to the brake circuits. This unit has two outlets and a 36.9 mm bore.
What vehicles does the M630454 fit?
It's a direct-fit replacement for 2007-2008 Chevrolet and GMC HD trucks and vans, including Silverado/Sierra 2500 HD and 3500 HD, Express/Savana 2500/3500, Suburban 2500, and Yukon XL 2500. See the Buyer's Guide tab.
Is this master cylinder new or remanufactured?
It's 100% new, built entirely from new materials and not remanufactured. The aluminum housing is constructed to match the casting material of the original part.
Does it include the reservoir, sensor, or mounting hardware?
The reservoir and sensor are included. Mounting hardware is not included; consult the vehicle service information for the correct fasteners and whether they may be reused.
What are the outlet and bore specifications?
It has two outlets with M12 x 1.0 threads at a 1 mm pitch and a 36.9 mm bore, and is made to meet rigorous SAE International standards.
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