Upgrading to servo on 1973 ; the new master cylinder has 3 ports, the original m/c used one port for the front and one for the back. Should I use the 2 front ports, one for each front wheel or block one off and use one port for both front wheels. I assume the back port goes to rear brake compensator as before. Any advice much appreciated.
Isn't the 3rd hole for the brake switch? My new Brazilian MC had 4 ports, so I did fronts to the front two ports and the rears use the single port to the bias valve. Last rear port was for Switch. Been on for years now and brakes normally in all conditions.
The rear port in the master cylinder is for the front brakes, the port at the front connects to the rear port on the compensator and the front port on the compensator connects to the rear brakes.
It will work connected backwards, as you have discovered, but the brake balance would be better if it were connected correctly.
