bad caliper or air in the lines?

[Tom]

Last night I replaced the front left caliper on my 79, and bleed all the brakes. Took it for test drive. It seemed like either the brakes were holding or the rims were still rubbing on the caliper bracket [my guess was #2]

So I went to drive it to the exaust shop today to have the exaust raised up. On the way I had several problems. #1- after braking, the steering wheel would pull to the left. It would stop after a while.
#2- when coming up to a stop sign, I hit the brakes. They went strait to the floor, and my brake light came on. I pumped em again, which gave me slight brakes, and I slammed the pedal down. I stoped just in time. After I released the pedal, the brakes wouldnt un-lock. I had to use a lot of gas pedal to get moving, and they gradually let go. I only went about 15ft before my next turn, and when I hit the brakes then they worked ok like before.

So, does this sound like air in the system? Would air cause one caliper to lock up like this? Thanks for any help.