Dorman M390177 Brake Master Cylinder

Reliable Brake Master Cylinder for Buick, Chevrolet, Oldsmobile, Pontiac

The Dorman M390177 Brake Master Cylinder is engineered to restore proper brake hydraulics in select GM vehicles. Designed for models like the Buick Regal, Chevrolet Lumina, Oldsmobile Cutlass Supreme, Pontiac Grand Prix, and Monte Carlo, this master cylinder ensures consistent brake fluid pressure and pedal feel.

• Master cylinder bore diameter: 24 mm for precise hydraulic control
• Constructed from durable aluminum material for corrosion resistance
• Includes reservoir for brake fluid storage and monitoring
• Equipped with a sensor to support brake system diagnostics
• Four outlet ports with secondary outlet thread diameter of 10 mm
• Rearward outlet size: M10 x 1.0 thread and unthreaded for versatile installation
• Package contains the master cylinder unit; mounting hardware not included

Product Details and Specifications

The Dorman M390177 master cylinder is crafted from aluminum, providing a lightweight yet robust component that resists corrosion and wear. Its 24 mm bore diameter is calibrated to deliver consistent hydraulic pressure, essential for safe braking performance. The included reservoir allows for proper brake fluid containment and monitoring, while the integrated sensor supports vehicle brake system diagnostics, helping maintain system integrity. With four outlets and a secondary outlet thread diameter of 10 mm, this master cylinder accommodates complex brake line configurations found in Buick Regal, Chevrolet Lumina, Oldsmobile Cutlass Supreme, Pontiac Grand Prix, and Monte Carlo models. The rearward outlet features an M10 x 1.0 thread and an unthreaded option, offering flexibility during installation.

Compatible Vehicles and Applications

This brake master cylinder is compatible with the following makes and models:

• Buick Regal
• Chevrolet Lumina
• Oldsmobile Cutlass Supreme
• Pontiac Grand Prix
• Pontiac Monte Carlo

It is designed to replace worn or failing master cylinders in these vehicles, restoring proper brake hydraulic function and pedal response.

Common Issues Addressed by This Master Cylinder

• Spongy or unresponsive brake pedal
• Brake fluid leaks from the master cylinder or reservoir
• Brake warning light activation due to sensor faults
• Reduced braking efficiency or inconsistent brake pressure
• Contaminated or deteriorated brake fluid reservoir

Installation Notes and Tips

Installation of the Dorman M390177 master cylinder requires careful attention to brake system bleeding procedures to remove air and ensure proper hydraulic pressure. Mounting hardware is not included, so existing hardware should be inspected and replaced if necessary. Verify compatibility with your specific vehicle model and year before installation. Sensor connections must be securely attached to maintain brake system diagnostics functionality.

Quality Assurance and Warranty

Dorman manufactures this brake master cylinder to meet or exceed OEM specifications, using quality aluminum materials and precise engineering. The product includes a sensor to support vehicle diagnostics and is designed for durability and reliable performance. Warranty coverage details should be confirmed at the point of purchase, as they may vary by distributor.