How to Bleed Your Brakes
70% to 80% of all low or soft pedal issues are caused by air being trapped in the hydraulic lines. It is absolutely necessary to remove any air in the brake system to achieve maximum stopping performance. Many brake systems can have loops or high spots, which will create an easy place for air to get trapped in the lines. When applicable, and you’ve checked the integrity of your booster and master cylinder and confirmed there are no leaks in the brake system, there are four basic methods that we recommend to bleed your brake system.
NOTE: Whenever you have purchased a new master cylinder you should always bench bleed it before you install the new part.