The Stovebolt Site Forums The Shop Area The HiPo Shop Calling all Brake experts....

OK....heres the story.
I changed out the disc brakes on my Mustang 2 front end from the 9" Mustang rotors to the 11" Granada rotors with GM Metric calipers, new brackets, etc. When switching over the brake lines, I did not drain down the Master Cylinder too low as far as I know. I bled the new brakes / no air in the lines, however, I cannot get the pedal pressure to come back up. Do I need to remove the Master Cylinder and bench bleed it or do I have another problem ? Master cylinder and booster are off a T-Bird, and worked fine before I started this adventure. All suggestions appreciated

How much bigger are the GM metric calipers over the Ford units? It maybe a matter of volume and the present master cylinder can not supply enough. You may need to upgrade to a bigger bore cylinder to provide the needed volume. Can you do a quick pump of the peddle and get it to hold solid up higher, or does the peddle slowly go to the floor with pressure on it. If it slowly drops, its probably air still in the system.
Sometimes you need to tap on the caliper to get the air out of them, and sometimes you need someone inside to pump up the peddle four or five times in quick secession, then open the bleeder while still holding down on the peddle.

Joe

Thanks for the tips Joe.
The GM calipers are definitely larger than the Mustang 2 units, although not huge difference. Let me try your suggestions for pumping the system as well as tapping the calipers - see if I can get any more ait out.

Did the prop valve slip to one side during the initial bleeding?
Scott