PB8531 | Universal 8" Dual Diaphragm Power Brake Booster: Zinc Finish

8" Dual Diaphragm Brake Booster, Zinc | PB8531 | Universal GM

PB8531 Universal 8" Dual Diaphragm Power Brake Booster: Zinc Finish

Get strong stopping power with a classic, factory-style look. The PB8531 packs two diaphragms into an 8" booster, so it delivers the firm, confident pedal of a much larger unit in a smaller package. Its zinc finish has the look of original-equipment boosters, so it suits restorations and resto-mods as well as street rods and muscle cars. The zinc plating also protects against rust and corrosion.

The compact 8" size clears tall valve covers, big-block engines, and aftermarket heads that often get in the way of a full-size booster. It uses standard GM bolt patterns, including the 3-3/8" square firewall pattern, so it works with common GM master cylinders and mounting brackets. Paired with the right brackets, it fits a wide range of classic GM cars.

Booster only. Mounting brackets, pedal rod extension, clevis, and master cylinder are not included. Choose the brackets that fit your vehicle, or reuse your existing brackets if they match the 3-3/8" square pattern.

Features

• 8" dual diaphragm design for strong braking assist
• Zinc finish for an original-equipment look
• Zinc plating resists rust and corrosion
• Compact size clears tall valve covers and big-block engines
• Standard GM bolt patterns, including the 3-3/8" square firewall pattern
• Universal fit with the correct mounting brackets
• Vacuum tested and quality inspected before shipping

Popular GM Applications (with the correct brackets)

• 1955–1957 Chevy Tri-Five: Bel Air, 210, 150, Nomad, and Sedan Delivery
• 1958–1970 full-size Chevy: Impala, Bel Air, Biscayne, and Caprice
• 1964–1972 GM A body: Chevelle, Malibu, El Camino, GTO, LeMans, Cutlass, 442, Skylark, and GS
• 1967–1972 GM F body: Camaro and Firebird
• 1968–1972 GM X body: Nova and Ventura II
• Street rods and custom builds that use GM-pattern brackets

Fitment depends on your brackets, pedal assembly, and master cylinder. Always confirm your setup before ordering. Also available in black powder coat (PB8531PC) and chrome (PB8531C).