I wanted to replace the Schraeder valve in a small wheelbarrow-type wheel today - it's an 8" wheel with an inner tube. Bought a new valve from a cycle shop (as directed by the automotive shop down the road, who didn't have any).
Only thing is, the new valve is about half the length of the old one, which has a pin about 0.5" long protruding downwards, surrounded by a spring which bears against a little brass bit at the very bottom (ie, inside the tyre).
My new valve physically fits OK, and retains air; however, is it OK? What's the purpose of the extra bit, why haven't I got it and does it matter?!
Cheers David