empty master cylinder

when i had my brakes done(rear) on my 71 it cost me almost $500 parts and labor. i would have done it myself but i didn't have time. if you have converted to the 73+ parts the price will be cheap if you do it yourself. but if you are still running the 4 piston cals its gonna get pricy... i have looked and the cheapest i have found is $125 EACH caliper. i have also inquired about having them rebuilt but no one wants to touch them except for a few resto shops and they want more to rebuild them than get rebuilt ones.. but check all your connections and lines. might have just sprung a leak.