Hi,
usually as long as you hadn't a leeking break pipe or the reservoir was completely empty, you shouldn't have air in the break lines.
Otrherwise you have a major fault somewhere and you should get this checked in a garage. Be carfully with doing any work at your break system. Negligence can be daedly :hang:
Anyway...
There are three main methods of bleeding: The Pump & Hold method, the Vacuum method and the Pressure method.
Pump & Hold generally requires two people, the other methods can be done by a sole person.
Pump and Hold Method:
One person pumps the brake pedal to compress the air, then holds pressure on it. The other person opens the bleeder valve to let out fluid and air, then closes the valve after the pedal has landed (to prevent air being sucked back in through the valve on the upstroke). The process is repeated, sometimes many times, for each wheel. Usually a length of clear tubing is connected to the bleeder valve and run to a container during the process, both to collect the toxic brake fluid and to better view the fluid and bubbles. The master cylinder reservoir must be replenished frequently, for if it goes dry the entire process must be redone. The cover must be left loose so that the fluid may be drawn, but should be in place so that fluid does not squirt out on the return stroke. It may be a good idea to not let the pedal bottom out during this procedure, as the master cylinder seals may be damaged by encountering accumulated sediment and / or corrosion.
The Pump and Hold Method, One Person Option:
This uses either a "one man" bleeder tool, comprising of a one way valve at the end of a length of tubing which is attached to the bleeder valve, or a special one way bleeder valve, such as the Russell Speed Bleeder. These methods have the disadvantage that air is sometimes sucked back into the system via the bleeder valve threads, this can be alleviated to a degree by using teflon tape on those threads, or by ensuring the valve is only opened by a small amount for the final stage of bleeding.
The Vacuum Method:
The master cylinder is topped off and the cover left loose. A specialized vacuum pump, such as the MityVac is attached to the bleeder valve, which is opened and fluid extracted with the pump until it runs clear of bubbles. Once again, the master cylinder reservoir level must be maintained. The vacuum method can also draw in air via the bleeder threads.
The Pressure Method:
A specialized pressure pump, such as the Motive Product Power Bleeder is attached to the master cylinder and filled with fluid. The pump is used to pressurize the system to about 10psi, and the bleeder valves are opened one at a time until the fluid is clear of air. One advantage to this system is that the pump reservoir usually holds enough fluid that running dry is not likely. This is the method most professional shops use, though they use commercial equipment instead of the above mentioned unit.
On the Scooby you typically start with the wheel furthest from the master cylinder; always the rear passenger wheel, then goes to the rear driver's wheel, front passenger wheel, and finally the driver's front wheel; (see the technical manual for the vehicle for proper procedure.)
For further information, see here:
http://www.stoptech.com/tech_info/wp_howto_bleedbrakes.shtml
Let me know, if you have further questions.
Good pumping
Akki
