Speedway Single Diaphragm Power Brake Booster, 7 Inch, Chromate Finish

Info

Notes

How to test your brake booster vacuum:

The valve where the vacuum line plugs in is a one way valve and is the first thing to check. Next with the car not running pump the brakes several times to remove any residual vacuum in the booster. Now push the brake pedal firmly down and hold pressure on the pedal, start the engine and when the vacuum reaches the booster the pedal should go down slightly. If it doesn’t move at all or if it goes down over an inch or more there is probable cause for concern. Next install a vacuum gauge in the line at the booster, start the engine and check the available vacuum. For full assist you need 18-20” of vacuum available.

This booster accepts master cylinders designed for a boosted brake system that have 3-3/8” center to center mount pattern. Depending on the application Speedway offers 1” bore GM style master cylinders for the front disc and rear drum vehicles under part number 91031445 or for the four wheel disc applications we offer a 1-1/8” bore master cylinder under part number 91031440. We also carry several other options in chrome, polished aluminum, and performance versions from CPP. 

Installation Note: Before installing the master cylinder onto the booster, you may need to make an adjustment.  The pushrod on the brake booster should protrude 1/16" from the face of the booster to insure proper engagement with the master cylinder.

Notes

Length from mount face to M.C. mount face is 3-5/8". Pushrod extends 4" from mount face and has 3/8"-24 threads. Mount bolts are 5/16"-20 x 7/8". M.C. mount studs are 3/8"-18 x 1-1/16".