Wilwood Left Combination Valve and Black Mustang Master Cylinder Kit, 15/16-inch Manual Bore

A black E-coated body and the Mustang-specific pedal eyelet identify this 15/16-inch tandem kit. The supplied left-side valve, bracket and formed tubing keep the master and adjustable rear-pressure control together without merging the two brake circuits. Established in 1977 by Bill Wood, Wilwood Engineering designs and manufactures disc brake systems from its base in Camarillo, California. Calipers, fittings, rotors, valves, master cylinders and brake lines serve its motorsport, street-performance and specialized applications. The full assembly, including its mating connections and operating requirements, governs the correct part selection.

Technical Details

• Manufacturer part number: 261-14158-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: 13.65"
• Mounting centers: 3.22–3.40"
• Pushrod dimensions: 5.75"
• 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

Check the classic Ford Mustang manual pedal against the associated 1964–1972 master family and the supplied eyelet. Full piston return, adequate stroke and the correct bore for the converted brakes are necessary even when the firewall pattern matches.

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

With more than 20 years of experience, PMB Performance can help compare the specified part with the assembly you are servicing. Include the existing part identification and relevant hydraulic dimensions.