Just installed new master (brake) cylinder in 85 300TD. Did bench bleed on it prior to install. Fluid was full (both reservoirs) - brakes were fine. I did NOT (yet) bleed system - (When I installed cylinder - did not "allow that much air" into lines) - Would this cause pedal to go farther down (not all the way to floor) - but further down than usual - incrementally (As I pus harder - it will give) - It will do this until I pump it up - then it might do it again the next day.

Thanks Steve

Yes. Bleed your brakes.

You only need to bleed it if there's a problem. If its just the master cylinder what little air got in would come out okay. I had a car where all the brake lines were run with no low spots, that is places to trap air, and I never had to bleed them to get air out.

However, if its been a while you should take this opportunity to bleed them. Also some dirt may have gotten in the lines.