Problem: Brakes work fine, but pedal won't come back up afterwards. I have to pull it back up with my foot every time I use it.
The car was sitting for several months without being used in a wet environment (Oregon). It almost feels as if it is just rusted, but I can't believe that is it. I tried spraying WD-40 up into the pedal mechanics, but can't really get up into it without severe dis-assembly.

I was leaning toward replacing the brake booster, but thought I would check with the forum before I started throwing money at the problem?

Is there any real difficulty with replacing the booster? Is this likely my problem?
Any help, suggestions or comments would be greatly appreciated!