vaccum advance question

[76bonanza]

I have an advance problem.

First I have a leak in the rear of my canister I can stick my finger back there and it sucks it up to a little hole in the rear. I am guessing that is not good?

I get no advance at idle if I hook it up to full vaccum I am guessing that is not good either.

So is my advance bad? I have an accell distrubuter can I just replace the advance and is it easy? Also If I drive it for a while like it is will it hurt the motor?

Thanks for all your help.