Dorman M639012 Brake Master Cylinder

Overview of Dorman Brake Master Cylinder M639012

The Dorman Brake Master Cylinder M639012 is designed specifically for Chevrolet Astra models, providing reliable brake hydraulics performance. Crafted from durable cast iron, this master cylinder ensures consistent braking pressure and long-lasting service.

• Master cylinder bore diameter: 0.875 inches
• Material: Cast iron construction for durability
• Number of outlets: 4 for efficient brake fluid distribution
• Rearward outlet size: M10 x 1.0 thread
• Secondary outlet thread diameter: M12 x 1.0 with 1.0 thread pitch
• Package includes the master cylinder only; reservoir and mounting hardware not included
• Sensor not included

Detailed Product Description

This Dorman brake master cylinder (part number M639012) is engineered to meet the specific hydraulic requirements of Chevrolet Astra vehicles. The 0.875-inch bore diameter allows for precise brake fluid pressure control, essential for safe and responsive braking. Constructed from cast iron, the master cylinder offers strength and resistance to wear under demanding conditions. It features four outlets, including a rearward outlet sized M10 x 1.0 and a secondary outlet with M12 x 1.0 thread diameter, ensuring compatibility with the vehicle's brake lines and fittings. Note that this unit does not include a reservoir or sensor, and mounting hardware is not provided, so these components must be sourced separately if needed.

Common Applications and Problem Resolution

• Restores proper brake fluid pressure in Chevrolet Astra brake systems
• Replaces worn or leaking master cylinders causing brake pedal sponginess
• Addresses brake fluid leaks from damaged or corroded master cylinders
• Improves brake system responsiveness and safety
• Suitable for vehicles experiencing inconsistent brake pedal feel or pressure loss

Installation Notes and Tips

• Ensure compatibility with Chevrolet Astra models before installation
• Bleed the brake system thoroughly after installation to remove air
• Verify thread sizes (M10 x 1.0 and M12 x 1.0) match brake line fittings
• Mounting hardware and reservoir must be installed separately as they are not included
• Inspect brake lines and sensors for wear or damage during replacement

Quality Assurance and Warranty

Dorman manufactures this brake master cylinder to meet or exceed OEM specifications for Chevrolet Astra vehicles. The cast iron construction provides durability and resistance to corrosion. While specific warranty details are not provided here, Dorman typically offers limited warranties on their brake hydraulic components. It is recommended to consult the product packaging or Dorman’s official resources for exact warranty terms.