Thanks to both of you :-)
The travel is ok...but I simply cannot make it move by mouth. It's simple too hard to move.
I've read in several forums you should be able to move it by mouth.
The strange thing is I think my vacuum unit is OK - it holds the air pressure at least.
I mean, not very complicated unit, simply a membran operated by air pressure.
Question is HOW hard is the vacuum pressure, or should be at least?
Further, could the pin be stuck in some way, inside the unit?
Again. thanks guys!! Really appreciate your help here :-)