Turn brake-pedal effort into the hydraulic pressure that operates your brakes with the Dorman - First Stop Brake Master Cylinder M98953. It drops in as a direct-fit replacement for a range of 1975-1983 Chevrolet and GMC trucks — including the Chevrolet C30, G30 and P30 and the GMC C35, K3500 and P3500 (see the Buyer's Guide tab for the full list) — where it develops the hydraulic pressure that pushes brake fluid out to the wheel circuits.
This unit has two outlets, a 1.313 in bore, and a 1/2-20 rearward outlet size, and it includes the reservoir. No sensor and no mounting hardware are included, so consult the vehicle service information for the correct fasteners and whether they may be reused. A slowly sinking or spongy brake pedal or unexplained fluid loss can be signs the master cylinder needs attention — if a failed master cylinder is the cause, this replaces it; diagnose the cause before replacing. Country of origin: China.
Interchange: 18M71 · 783-44005 · 78344005 · 83-44005 · 8344005 · M900232 · 100-2579 · 1002579 · M-86005 · M86005 · 11584 · 13-1584 · 131584 · 10-1584 · 101584 · 130.66005 · 131.66005 · MC98953 · 355-47140 · 35547140 · 14008238 · 14036115 · 6260725 · 98953 · M1584 · NM1584 · 2539017 · MC39017 · F86510 · F98953 · MC86510 · Manufacturer part number M98953
This part cross-references / interchanges with the following part numbers:
What does this brake master cylinder do?
It converts the force you apply at the brake pedal into hydraulic pressure that pushes brake fluid out through its two outlets to the wheel circuits.
Does it come with a reservoir?
Yes, the reservoir is included. A sensor and mounting hardware are not included.
What are its key specifications?
It has a cast iron housing, a 1.313 in bore, two outlets, and a 1/2-20 rearward outlet size, and is made entirely of new materials to meet SAE International standards.
Which vehicles does it fit?
It fits a range of 1975-1983 Chevrolet and GMC trucks such as the C30, G30, P30, K30, C35, G35, K35, P35, C2500, C3500, K3500 and P3500. See the Buyer's Guide tab for the full list with years.
What are the signs my master cylinder may need replacing?
A brake pedal that slowly sinks or feels spongy, or unexplained brake-fluid loss, can be signs. Have the cause diagnosed, since these symptoms can have other causes.
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.