Dorman M66712 Brake Master Cylinder

Name: Dorman M66712 Brake Master Cylinder
Brand: Dorman
SKU: BKKX-M66712
Price: 84.53 USD
Availability: InStock

N/A

22 vehicles fit this part

Select your vehicle to confirm fitment

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OE Direct Replacement — Bolt-on fit, no modifications needed

Fitment: Buick, Pontiac, Oldsmobile, and Cadillac, Electra, Estate Wagon, LeSabre, Riviera, Wildcat, Bonneville, Catalina, Executive, Grand Prix, 98, Delta 88, Delmont 88, Calais, DeVille, Eldorado, Fleetwood, and Toronado

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Reliable Brake Master Cylinder for Classic GM Vehicles

The Dorman M66712 brake master cylinder is engineered to restore proper brake hydraulics in select Buick, Cadillac, Oldsmobile, and Pontiac models. Designed with durable cast iron and a built-in reservoir, this master cylinder ensures consistent brake fluid delivery for safe stopping performance.

Master cylinder bore diameter: 1 inch
Constructed from cast iron for durability
Includes reservoir for brake fluid
Two outlets with rearward outlet size of 9/16-18
Secondary outlet thread diameter: 0.5 inch
Mounting hardware not included
Part number: M66712

Durable Construction and Precise Specifications

The Dorman M66712 brake master cylinder features a 1-inch bore diameter made from cast iron, providing strength and resistance to wear. Its integrated reservoir simplifies brake fluid management, while the two outlets—including a rearward outlet sized at 9/16-18 and a secondary outlet with 0.5-inch thread diameter—allow for proper brake line connections. This master cylinder is designed specifically for classic GM vehicles such as the Buick LeSabre and Riviera, Cadillac DeVille and Eldorado, Oldsmobile Delta 88 and 98, and Pontiac Bonneville and Grand Prix, ensuring compatibility and reliable performance.

Compatible Vehicles and Applications

This brake master cylinder is compatible with a range of Buick, Cadillac, Oldsmobile, and Pontiac models, including:

Buick 98, LeSabre, Riviera
Cadillac DeVille, Eldorado, Fleetwood
Oldsmobile Delta 88, 98
Pontiac Bonneville, Catalina, Grand Prix, Toronado

It is ideal for restoring brake hydraulics in these vehicles, especially when experiencing issues related to brake fluid pressure and pedal feel.

Common Issues Addressed by This Master Cylinder

Spongy or soft brake pedal response
Brake fluid leaks from the master cylinder reservoir
Reduced braking efficiency or uneven brake pressure
Brake warning light activation due to hydraulic failure
Brake pedal sinking or failure to maintain pressure

Installation Notes and Tips

Installation of the Dorman M66712 master cylinder requires proper brake line connection to the two outlets, matching the specified thread sizes. Since mounting hardware is not included, ensure you have the correct bolts and fittings for your vehicle. Bleeding the brake system thoroughly after installation is essential to remove air and restore full braking function. Professional installation is recommended for safety and optimal performance.

Quality Assurance and Warranty

Dorman manufactures this brake master cylinder to meet or exceed OEM specifications, using cast iron for long-lasting durability. While mounting hardware is not included, the product undergoes quality checks to ensure fitment and function. Please refer to Dorman's warranty policy for coverage details on the M66712 part.

Brand	Dorman
Part Number	M66712
Master Cylinder Bore Diameter	1
Master Cylinder Material	Cast Iron
Mounting Hardware Included	No
Number of Outlets	2
Package Contents	Master Cylinder
Rearward Outlet Size	9/16-18
Reservoir Included	Yes
Secondary Outlet Thread Diameter	0.5
Sensor Included	No

This part fits 22 vehicles. Search below:

Year	Make	Model	Position	Notes
1970	Buick	LeSabre	N/A	Compatible with vehicles with Bendix brakes, 1 inch bore size.
1970	Buick	Riviera	N/A	Compatible with vehicles with Bendix brakes, 1 inch bore size.
1970	Pontiac	Bonneville	N/A	Compatible with vehicles equipped with Bendix brakes and power brakes, with a 1-inch bore.
1970	Pontiac	Catalina	N/A	Compatible with vehicles equipped with Bendix brakes and power brakes, with a 1-inch bore.
1970	Pontiac	Grand Prix	N/A	Bore: 1 In; Front Drum Brakes; For vehicles with Bendix Brakes and Power Brakes.
1969	Oldsmobile	98	N/A	Front Drum Brakes w/Bendix Brakes; Bore: 1 In.; Power Brakes
1969	Oldsmobile	Delta 88	N/A	Fits vehicles with Bendix brakes, 1" bore, for power brakes.
1969	Pontiac	Bonneville	N/A	Compatible with vehicles equipped with Bendix brakes and power brakes, with a 1-inch bore.
1969	Pontiac	Catalina	N/A	Compatible with vehicles equipped with Bendix brakes and power brakes, with a 1-inch bore.
1968	Oldsmobile	98	N/A	Front Drum Brakes w/Bendix Brakes; Bore: 1 In.; Power Brakes
1968	Oldsmobile	Delta 88	N/A	Fits vehicles with Bendix brakes, 1" bore, for power brakes.
1968	Pontiac	Bonneville	N/A	Fitment: Compatible with vehicles equipped with Bendix brakes, 1-inch bore, standard duty brakes, and power brakes.
1968	Pontiac	Catalina	N/A	Fitment: Compatible with vehicles equipped with Bendix brakes, 1-inch bore, standard duty brakes, and power brakes.
1968	Pontiac	Grand Prix	N/A	Fitment: Compatible with vehicles equipped with Bendix brakes, 1-inch bore, standard duty brakes, and power brakes.
1967	Buick	LeSabre	N/A	Fits vehicles with Bendix brakes, 1" bore, for power brakes.
1967	Cadillac	DeVille	N/A	Compatible with vehicles equipped with Bendix brakes and power brakes, with a 1-inch bore.
1967	Cadillac	Eldorado	N/A	Fits vehicles with Bendix brakes, 1" bore, for power brakes.
1967	Cadillac	Fleetwood	N/A	Compatible with vehicles equipped with Bendix brakes and power brakes, with a 1-inch bore.
1967	Oldsmobile	Toronado	N/A	1 In. bore size, suitable for power brake systems.
1967	Pontiac	Bonneville	N/A	Fitment: Compatible with vehicles equipped with Bendix brakes, 1-inch bore, standard duty brakes, and power brakes.
1967	Pontiac	Catalina	N/A	Fitment: Compatible with vehicles equipped with Bendix brakes, 1-inch bore, standard duty brakes, and power brakes.
1967	Pontiac	Grand Prix	N/A	Fitment: Compatible with vehicles equipped with Bendix brakes, 1-inch bore, standard duty brakes, and power brakes.

* Always verify fitment with your vehicle's VIN if unsure. Submodel & trim restrictions may apply.

This part directly replaces or is cross-referenced with the following part numbers:

10-13281132813-1328130.620151489981253623683-36015F64890M-82015M1328M900095MC501390

Cross-reference numbers are provided for identification purposes only. Always confirm fitment before ordering.