I have a feeling the rave valves on my sled weren't put back together properly by the previous owner. There is zip ties holding the rubber bellows to the plastic piece and looks like the plastic piece was overtightened to the valve itself because it has poked a hole through the plastic. Does somebody have a good breakdown of the rave valves that they would like to share with me? Also, which way does the beveled part of the valve itself go, or is there a marking on it indicating "top"? Thanks again!