Wilwood Left Proportioning Valve and Black 15/16-inch Master Cylinder Kit with Pushrod

The black 15/16-inch master offers a middle bore choice for a custom manual-brake system. This complete master-and-valve package includes the threaded rod, a left-hand valve bracket and the formed tubes that preserve front/rear circuit separation. Wilwood Engineering's design and manufacturing work covers disc brake systems for specialized applications, street performance and motorsport. Founded by Bill Wood in 1977, the company operates from Camarillo, California. Its component range includes master cylinders, fittings, brake lines, rotors, valves and calipers, each requiring selection in the context of the complete brake system.

Technical Details

• Manufacturer part number: 261-13626-BK
• Material: Aluminum
• Cylinder bore: 15/16"
• Pressure circuits: 2
• Stroke Length: 1.10 in
• Reservoir Type: Integral
• Fluid capacity: 8.0 / 4.8 oz
• Flange-to-end length: 8.15"
• Overall Length: 12.26"
• Mounting centers: 3.22–3.40"
• Pushrod dimensions: 4.11" x 3/8-24
• Finish: Black E-coat
• Native pressure ports: 1/2-20 at both circuits; use the correct included outlet adapters and seal washers
• Circuit outlet adapters: Primary: 3/8-24 or 1/2-20 inverted flare; secondary: 3/8-24 or 9/16-18 inverted flare
• Hydraulic relationship: Equal pressure output from the two circuits before external proportioning; 2:1 primary/secondary volume relationship
• Service: Factory rebuild only; do not disassemble the tandem piston assembly
• Kit contents: Master cylinder, left-side combination proportioning valve and bracket, formed stainless connecting tubes and mounting hardware
• Combination-valve functions: Adjustable rear pressure, isolated front/rear circuits, front-line junction and hydraulic brake-light switch

Fitment & Compatibility

Compare the required fluid volume with the pedal leverage before selecting this bore. Verify that the clevis accepts the supplied rod and that the valve knob, hard lines and reservoir cover remain accessible after installation.

Manufacturer Documents

• Wilwood product specifications
• Wilwood DS985 instructions and specifications
• Wilwood FL331 instructions and specifications
• Wilwood FL162 instructions and specifications
• Wilwood DS487 instructions and specifications

The component must suit the completed installation. PMB Performance draws on over 20 years of experience to help you check the part identification, mating connections and required operating dimensions.