If you need to bleed the caliper with the broken bleeder screw, unbolt it and hold it so the banjo bolt is at the high spot, then crack that bolt open to expel any air. If you think there might be a little air in the line yet, squeeze the piston back in. That will push the fluid back up to the reservoir and wash any air bubbles with it into thee reservoir.
One real important note. Never press the brake pedal more than half way to the floor. Crud and corrosion build up in the lower halves of the bores in the master cylinder where the pistons don't normally travel. Running the pedal to the floor runs the lip seals over that crud and can rip them.
A second problem that only pertains to GM front-wheel-drive cars is a valve will trip in the master cylinder that blocks fluid from flowing to one front wheel and the opposite rear wheel. Due to changes made in the alignment and the suspension geometry, you will very likely not notice a brake pull, but only one front brake will apply. The pedal will feel normal too. Most people don't even realize there's a problem until they've replaced the front pads two or three times and they're always worn out on one side and look like new on the other side. The other symptom is you can't get that one caliper to flow any fluid. The ONLY fix I've ever found that works to reseat that valve is to use compressed air to give a short fast squirt of air into one of the opened bleeder screws on a wheel that isn't flowing, then let it gravity bleed. If you press the brake pedal too far when just working the caliper pistons out after installing new pads, one will contact the rotor first and start to build up pressure before the other side. That can be enough to trip that valve. That's why I asked if the fluid is flowing freely. There could be air in the line yet to a wheel with a blocked port.
Sunday, October 16th, 2011 AT 4:12 AM