Make sure the rubber brake lines to the calipers are not expanding when you depress the brake pedal. If they are not, chances are the master cylender is bad. It doesn't happen often, but forcing the old fluid back through the master cylender in the wrong direction can cause the plungers to get damaged.
When I was trained, (I believe it was a Bendix program), I was taught to release the fluid from the caliper bleeder. It is actually easier. I take a large screwdriver as a pry bar, place it between the rotor and inner pad, break the bleeder loose, and simply pry the inner pad and piston in and lock the bleeder when I release pressure. THis is done before I even loosten the caliper. Front brake pads take about 10 minutes per side. Also, by doing this, there is no old brake fluid being forced back through the system in the wrong direction. Keep in mind, the way you do it isn't wrong, I was taught differently. Also, if the bleeder is really rusted, it isn't a good idea.
As far as the problem you have, if the hoses are good, there are no leaks. The master cylender is bad. Try this, place pressure on the brake pedal and see if it slowly goes to the floor.
Let me know what you find.
Thursday, October 7th, 2010 AT 9:41 PM