I have a 86 GN thats getting air bubbles in the one half of the master cylinder reservoir. It is the power master brake system and I did have to replace a couple of brake lines that blew out. I bled the system and made sure the rear brakes are adjusted. The brake light is still coming on when I apply the brakes and the pedal goes down about 1/3 of the way. Other than that it seems to stop fine.