Hi,I have a 1987 245 that has an intermittant braking problem. Sometimes it stops fine, sometimes even with heavy pressure it barely stops. Recently I replaced front rotors, turned rear rotors and installed new PBR pads. One front rotor had been badly warped. Master cylinder was replaced about 2 years ago, but front tank of master cylinder is often low. (very slow leak).None of the calipers appear to be leaking, but I do see some fluid on the front of the booster around the master cylinder. Also when I stop the car I hear a hissing under the dash which all friends say is a sure sign of a bad booster. Looking at the booster, it seems hard for fluid to leak in from the master cylinder, but I know it happens on US cars. Any thoughts? Thanks, zootmancars