Bleeding brakes with two people works by pushing on the brake pedal and releasing air through the bleeders simultaneously. In order for this method to work, the person who is depressing the brake pedal must listen carefully or risk sucking air back up into the lines -- clear communication is key.
Here's how to bleed the breaks with a friend:
Step 1: Once the car is up on jacks and the wheels have been removed, take the rubber cap off each bleeder screw. Position your box-end wrench to loosen the bleeder valve, but don't do it yet. First, attach the clear tubing over the nipple of the bleeder valve and put the other end in a bottle to catch the fluid.
Step 2: Ask your friend to pump the brake pedal three times, and then hold the pedal down as far as it will go. Your friend must hold it there until you say it's time to release it.
Step 3: Once your friend is holding the brake pedal in the completely pressed down position, turn the bleeder valve 1/4 turn. This will release the brake fluid and air. Only keep the valve open a second or two before closing it off again by tightening the screw. Your friend will feel the pedal go toward the floor of the car. Once the screw is closed, ask your friend to release the brake pedal. Repeat this bleeding process until there are no air bubbles in the fluid that is in the clear, plastic tubing.
Step 4: After all the brakes have been bled, test the brake pedal for firmness. Make sure it does not feel spongy when depressed. Visually inspect all the bleeder screws for any signs of leakage.
Step 5: If everything checks out, replace the rubber caps on the bleeder screws, put your tires back on and take your vehicle for a spin. Be careful to test the brakes before heading out onto the open road. Use caution until you know your brakes are in good working order. [source: Comeskey]