Dorman M105801 Brake Master Cylinder

Reliable Brake Master Cylinder for Select GM Vehicles

The Dorman M105801 brake master cylinder is engineered to restore proper brake hydraulics in various Buick, Chevrolet, GMC, Oldsmobile, and Pontiac models. Designed with durable cast iron construction and a built-in reservoir, this master cylinder ensures consistent brake fluid delivery for safe stopping performance.

• Constructed from cast iron for strength and durability
• Includes reservoir for brake fluid storage
• Dual outlet design with 24 mm (1-1/4 inch) bore diameter
• Rearward outlet size: 1/2-20 thread
• Secondary outlet thread diameter: 9/16-18
• Compatible with multiple GM models including Buick Bonneville, Chevrolet Malibu, and GMC S15 Jimmy
• Part number M105801 for precise identification

Detailed Product Features and Specifications

This Dorman brake master cylinder features a cast iron body that provides long-lasting resistance to wear and corrosion. The integrated reservoir simplifies installation and maintenance by housing the brake fluid directly on the unit. With a bore diameter of 24 mm (1-1/4 inch), it supports effective hydraulic pressure generation. The master cylinder includes two outlets: a rearward outlet with a 1/2-20 thread and a secondary outlet with a 9/16-18 thread, allowing compatibility with various brake line configurations. Note that mounting hardware is not included, so existing hardware or separate purchase may be necessary.

Compatible Vehicles and Applications

This master cylinder is compatible with a range of GM vehicles, including:

• Buick Bonneville, Riviera
• Chevrolet Malibu, Monte Carlo, El Camino, S10, S10 Blazer
• GMC S15, S15 Jimmy
• Oldsmobile Cutlass Calais, Cutlass Cruiser, Cutlass Supreme, Grand Prix, Regal
• Pontiac Grand Prix

Use part number M105801 to ensure correct fitment for these models.

Common Brake System Issues Addressed

• Brake pedal sinking or sponginess due to master cylinder wear
• Brake fluid leaks from a damaged or corroded master cylinder
• Inconsistent brake pressure affecting stopping performance
• Brake warning light activation related to hydraulic failure
• Reduced braking efficiency in Buick, Chevrolet, GMC, Oldsmobile, and Pontiac vehicles

Installation Notes and Tips

• Verify compatibility with your vehicle’s make, model, and year before installation
• Bleed the brake system thoroughly after installation to remove air
• Use appropriate brake fluid as specified by the vehicle manufacturer
• Inspect brake lines and fittings for wear or damage during replacement
• Mounting hardware is not included; retain original hardware or acquire separately

Quality Assurance and Warranty

Dorman manufactures this brake master cylinder to meet or exceed OEM standards for fit and function. The cast iron construction and integrated reservoir contribute to reliable brake system performance. While specific warranty details may vary, Dorman typically offers a limited warranty covering defects in material and workmanship. Consult product documentation or the supplier for exact warranty terms.