How to Properly Bench Bleed the Master Cylinder with Wilwood
Hydraulic brakes for automotive use first appeared in 1921 on the the Model A Duesenberg. Chrysler, Dodge and others followed a decade later, with Ford being the holdout on adopting the innovation until 1939.
Refinements, such as self adjusting brakes, vacuum assist, anti-lock braking, hydroboost and others have come along in the ensuing 90 years, but the fundamental operation remains unchanged since the inventor, Malcolm Lougheed, first proposed it in 1918. He later changed his name to Lockheed – yeah, that Lockheed.
Air bubbles are the enemy of effective hydraulics and shade tree mechanics. The process of bleeding is used to get rid of any air that may be present in the components. Air in the brake fluid leads to a spongy feel to the pedal and reduced performance of the braking system.
Since it all starts from the master cylinder, that is the place you have to start whether you’re doing a simple replacement or a complete brake upgrade. Wilwood Engineering has produced a video to show you exactly how to get the air out of a new master cylinder. The job is a lot easier done on your workbench than after installing it in the car, so check it out below.