Dorman M39508 Brake Master Cylinder

Reliable Brake Master Cylinder for Geo and Toyota Vehicles

The Dorman M39508 brake master cylinder is designed to restore proper brake hydraulics in select Geo and Toyota models. Engineered with an aluminum body and integrated reservoir, this master cylinder ensures consistent brake fluid pressure for safe stopping performance.

• Compatible with Geo Prizm, Toyota Corolla, and Toyota Tercel models
• Master cylinder bore diameter of 0.813 inches for precise hydraulic control
• Durable aluminum construction for corrosion resistance and longevity
• Includes reservoir and sensor for complete brake system integration
• Two outlet ports with rearward outlet size M10 x 1.0 and thread pitch 1.0
• Secondary outlet thread diameter of 10 mm
• Package contains the master cylinder only; mounting hardware not included

Product Details and Specifications

The Dorman M39508 brake master cylinder features a robust aluminum body that resists corrosion and withstands the demands of brake hydraulics. Its 0.813-inch bore diameter is calibrated to provide accurate brake fluid pressure, essential for the proper function of the braking system. This unit includes a reservoir and sensor, allowing for seamless integration with the vehicle’s brake fluid monitoring system. The master cylinder has two outlets, including a rearward outlet sized M10 x 1.0 with a thread pitch of 1.0, and a secondary outlet with a 10 mm thread diameter, ensuring compatibility with the brake lines on Geo Prizm, Toyota Corolla, and Toyota Tercel models. Note that mounting hardware is not included with this part.

Compatible Vehicles and Applications

This brake master cylinder is specifically designed for use in the following vehicles:

• Geo Prizm
• Toyota Corolla
• Toyota Tercel

It is ideal for replacing worn or failing master cylinders in these models to restore proper brake function and safety.

Common Issues Addressed by This Master Cylinder

• Brake pedal sinking or sponginess due to internal leaks
• Brake fluid leaks from a damaged or corroded master cylinder
• Loss of brake pressure causing reduced stopping power
• Brake warning light activation related to sensor failure
• Inconsistent brake pedal feel or delayed brake response

Installation Notes and Tips

• Ensure brake fluid system is properly bled after installation to remove air
• Verify compatibility with vehicle model and year before installation
• Use appropriate tools for M10 x 1.0 threaded outlets to avoid damage
• Inspect brake lines and fittings for wear or damage during replacement
• Mounting hardware is not included; reuse existing hardware or source separately

Quality Assurance and Warranty

Dorman manufactures the M39508 brake master cylinder to meet or exceed OEM specifications for fit and function. The aluminum construction provides durability and corrosion resistance. This part includes a sensor and reservoir to maintain system integrity. While mounting hardware is not included, the product undergoes quality checks to ensure reliable performance. Warranty coverage details should be confirmed with the point of purchase or manufacturer.