Vacuum chamber necessary?

[MarquisGT]

The small round vacuum chamber for my 1990 E150 has a crack in it. The vacuum cylinders for the duct system won't work with a leak like that. I know I could get a used chamber from a junk yard (can't find them new), but I want to know if it is really necessary? The whole vacuum line and tank are dedicated to the climate controls so I don't think it would interfere with any other systems. I plugged the line after I removed the tank and everything operated fine. Am I going to damage anything if I don't re-install the tank? Thanks.