I still haven't got all the parts to put the entire RS hideaway headlights together but I'm trying to test the canisters to see if they're any good. They are brand new repros but have never been used for at least 4 years now. I tried to hook the vacuum line straight off the manifold to either side of one and it doesn't move the plunger in or out. If I hold my finger over the other fitting for a little bit and then let it go the plunger jumps in or out about an inch. is there any valid way to test them? If I get a vacuum pump/gauge, how much vacuum should I have?