I've never had much luck with junk yard stuff for electrics.... Seems most of it works about 3 times then it's back to the yard for a replacement!!!!! Nothing worse then getting a project all done then spend a month messing around with a bunch of old used stuff..... Takes a few more bucks to get the new stuff, but at least it will hold together...if you buy the good pieces.
For me it kind of comes down to price vs. value.....