Wilwood Left-Bracket Valve and Black Mopar Tandem Master Kit, One-Inch Bore, Four-Bolt Mount, No Pushrod

This one-inch compact tandem kit uses the Mopar four-bolt mounting arrangement with a left-side valve. Its input is supplied without a pushrod, requiring the actuation system to be matched separately. The disc brake systems Wilwood Engineering designs and manufactures include calipers, rotors, master cylinders, brake lines, valves and fittings. The company dates to Bill Wood's founding in 1977 and is based in Camarillo, California. Motorsport, specialized and street-performance applications all call for parts matched to the operating requirements of the full system.

Technical Details

• Manufacturer part number: 261-16797-BK
• Material: Aluminum
• Cylinder bore: 1.00"
• Pressure circuits: 2
• Stroke Length: 1.10 in
• Reservoir Type: Integral
• Fluid capacity: 7.8 / 4.7 oz
• Overall Length: 7.16"
• Mounting centers: 3.25 × 1.76"
• 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 9/16-20 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
• Flange-to-end references: Exact product page: 6.55 inches; DS-1520 dimensional drawing: 6.70 inches. Confirm the available installation envelope.
• Circuit routing: Primary outlet A feeds the axle with greater total effective caliper piston area, normally the front; secondary B feeds the lesser-area axle, normally the rear. Outlet locations are reversed from the original Mopar master cylinder; follow DS-1520.
• Linkage: Pushrod not included; match the existing or separately supplied actuation interface

Fitment & Compatibility

Compare the Mopar flange and booster rod with the master-cylinder input. Verify left bracket clearance and the supplied adapters' actual thread pitches.

Manufacturer Documents

• Wilwood product specifications
• Wilwood DS1520 instructions and specifications
• Wilwood FL162 instructions and specifications
• Wilwood DS1178 instructions and specifications

PMB Performance offers over 20 years of parts and brake-fitment experience. For a compatibility check, provide the existing assembly and the dimensions that govern the replacement.