I don't think a schrader will hold vacuum - at least not to any greater (negative) pressure than the spring holding the valve closed - when holding positive pressure the internal pressure also holds the valve closed, so seal clamping force goes up with the pressure it's holding.
If you were thinking of something that required positive pressure to move state-change temp (like butane, maybe) then they should work fine.
Also - at least some schrader valves stand up to butane and propane just fine - they're used as part of the gas regulation systems in a number of outdoor gas grills (usually with a diaphragm pushing the schrader open - but I digress).
Presta valves might work for vacuum as they screw shut rather than being pushed shut - but I don't think presta valves with threaded ends are very common (I've never seen one).
|