Brake Bleeding

When it comes to brake bleeding, there are 4 ways to bleed your brakes. 

The first method is where a friend or significant other pushes on the pedal while you open and close each bleeder screw. Using this method, be sure and check the brake reservoir fluid level often, as you don't want the brake reservoir to run dry, introducing air into the brake lines. If the reservoir runs dry, then you have to start all over, possibly testing the goodwill of your helper. If your Porsche has high mileage, be forewarned that this method may ruin the seals inside the master cylinder, as pushing the pedal to the floor moves the seals over areas in the master cylinder that don't normally see movement, tearing the seals.  Power bleeding, which uses an air source to keep brake fluid feeding the brake reservoir, only requires one person.  There are several power bleeders available (Eezibleed, Motive Power Bleeder, Ultimate Garage Brake Bleeder, others) ranging from $30 to $140, which either use a bicycle tire, or the like, for air pressure, or have a built-in air pump. Some build their own. The vacuum pump is another one person solution, however, there seems to be mixed success with this method. Last but not least, take your Porsche to someone else and let them bleed the brakes for you. You'll find when you start doing more drivers education events that you'll need to bleed your brakes more often.  I bleed mine before each drivers ed event.

Conventional wisdom says to start bleeding the wheel farthest from the master cylinder, usually the right rear, and progress left rear, right front, then left front. If you're bleeding your brakes more often than the factory recommendation, you should be OK bleeding each side as you jack it up. However, if you are flushing/replacing all your brake fluid, the right rear to left front direction should be used.  You should know if your calipers have one or two bleeder screws. When you tighten the bleeders, don't overdo it. The 911 factory spec is to tighten the bleeders to 3Nm or about 2 foot lbs., which isn't much.

Written by Bill Gregory for the "Challenge", monthly publication of the Connecticut Valley Region, Porsche Club of America.