With some of the older Compurs, you don't tension the shutter for B and T. In fact, I believe you cannot tension the shutter on B and T with some of the older Compurs.
Otherwise, I agree with Greg. The outer dial with the speeds probably isn't seated correctly. That's where I would start. Before you replace the other parts, turn the dial from T to the top speed (shutter untensioned) and see that it spins freely -- not easily, but freely.
What I'll sometimes do when I have trouble replacing the speed dial is to half tension and release the shutter a couple of times at around 150 or so. Then I'll change speeds and try again.