question about brakes

All the major wiring is done (a couple of instruments and two lights aren't wired properly) and the engine runs like a top. As soon as I can get a friend over to push the pedal while Ibleed the brakes, it will be finished. That brings up a question that worries me.

When the engine is turned off, the brake pedal is very firm, feels great. When I start the engine, the pedal goes to the floor beforfe engaging and the return is very, very slow.

I know the brakes need bleeding badly. I had the lines sitting disconnected for 2 months and plenty of air was pushed through during the varous mounting attempts.

Is the slow pedal return and pedal bottomingout because of the air in the lines or because of something I did wrong with the vacuum or whatever?

 

If you have vacuum assist brakes then it sounds like you may have a bad diaphram in the brake booster.