I split the 2 halves of my vetus waterlock muffler last fall to do some engine work (draincock replacement) and now can't get it to stop leaking at the seam. The clamp that holds the muffler together is made of 2 matching semi-circles of plastic with a captive nut/screw at each joint. Am I suppose to tighten the clamp until the ends of the clamp touch? - it looks like that is the case, but I have been reluctant to tighten that much for fear of breaking the plastic.