Alfa Romeo Repair: brake booster, rubber sleeve, brake booster

Question
I have repaired a brake booster in my 1971 RHD Guilia Super and the the brakes are intermittently staying on.The bleed process was OK, and when I clear the vacuum and apply slight pressure, the pedal goes down further, when the engine is started, indicating the booster(s) are working properly.

Answer
Do you have the firewall mounted booster or is it the remote mounted on the fenderwell. If it is the firewall (or conventional) unit, it is possible the the rod lengths are no longer correct. Between the booster and the master cylinder there should be 0.006" clearance with the mst/cyl piston all the way back.  The rod from the brake pedal must just contact the booster.

The only time I encountered an intermittant problem like this it took 3 tries until I found the real cause--it was a rubber sleeve traveling up and down the steering column and occasionally would drop enough to hold the brake pedal slightly on.