Dorman - First Stop Brake Master Cylinder P/N:M630759
Keep hydraulic pressure moving to every wheel with the Dorman First Stop Brake Master Cylinder M630793, a new unit that turns brake-pedal effort into line pressure. It is a direct-fit replacement for these applications (all engines): the 1998 and 2002-2007 Isuzu NPR, 2002-2007 Chevrolet W3500 and W4500 Tiltmaster, 2002-2007 GMC W3500 and W4500 Forward, and 2002-2007 Isuzu NPR-HD. Each listed application uses one per vehicle.
Dorman precision-engineered this master cylinder to replicate the original unit's design, function and performance on the listed applications. It uses new, high-quality materials for a safe, durable replacement.
Specifications: 1.25 in. bore diameter · 2 outlets · M10 x 1.0 rearward outlet size · 1/2-20 secondary outlet thread diameter · 4 mounting holes · single reservoir type.
In the box: the master cylinder and a bleeder kit. The reservoir, master cylinder cap, push rod, brake booster, sensor, mounting bracket and mounting hardware are not included. Consult the vehicle service information for the correct fasteners and whether they may be reused.
A soft or sinking brake pedal, brake fluid leaking at the cylinder, or a lit brake warning light can be signs that a master cylinder may need replacing. Air in the system, a leaking brake line or another hydraulic component can cause similar symptoms, so diagnose the cause before replacing the master cylinder.
Country of origin: China.
Interchange: 100-3913 · 11-3971 · 130.76010 · 355-47205
1003913 · 113971 · 13076010 · 35547205 · 97315166 · 8973151660 · MC391472 · F140752 · MC140752
This part cross-references / interchanges with the following part numbers:
Which vehicles does the Dorman M630793 fit?
It is listed for the 1998 and 2002-2007 Isuzu NPR, 2002-2007 Chevrolet W3500/W4500 Tiltmaster, 2002-2007 GMC W3500/W4500 Forward and 2002-2007 Isuzu NPR-HD, all engines, with one per vehicle.
Does this master cylinder come with a reservoir or cap?
No. The package contains the master cylinder and a bleeder kit; the reservoir, master cylinder cap, push rod, brake booster, sensor, mounting bracket and mounting hardware are not included.
What is the master cylinder made of?
The cylinder housing is cast iron. All rubber components are made of an EPDM compound that resists glycol-based brake fluid.
What are the bore and outlet specifications?
It has a 1.25 in. bore, two outlets, an M10 x 1.0 rearward outlet and a 1/2-20 secondary outlet thread, with four mounting holes.
What is the included bleeder kit used for?
It is used to bench bleed air from the new master cylinder before installation. Follow the vehicle service procedure for bleeding both the cylinder and the brake system.
WARNING: These products can expose you to chemicals including lead and phthalates, which are known to the State of California to cause cancer and birth defects or other reproductive harm. For more information go to www.P65Warnings.ca.gov.