I have a toilet that starts running about every 15 minutes for a short period of time. It is a Mansfield toilet and instead of a flapper, it uses a flush valve system. I can see where the seal is deteriorated but I haven't a clue how to replace it. It looks like the entire system has to come apart but that doesn't seem right. Is this something I need a plumber for or is there an easy fix? If handiness was on a scale of 1 to 10, I'm a 5 or 6. Thanks.

I installed a Lasco Fiberglass Shower Pan per the manufacturers directions about three years ago. I used four mounds of mortar for supporting the bottom as described in the instructions, surrounding but not contacting the drain area. This morning I was using our unfinished downstairs bathroom which is directly beneath the bathroom this shower is in. I noticed a small puddle of water on the floor, and traced it to the area underneath this shower. I could see where water was coming through the car decking (the subfloor for the upstairs bathroom). When inspecting the shower pan I found a crack in top layer of the base, about five inches from the drain. When I press on the pan the crack opens just slightly, so it appears this is where the problem is stemming from. I'm guessing this crack is about 3-4 inches from the nearest supporting mound under the pan. Obviously the permanent fix would be to tear out the whole thing and start fresh, but is there a temporary fix to repair the crack so I don't end up with a rotten floor under the pan? This crack wasn't there a couple days ago, so I know it hasn't been leaking for very long. By the way, my neighbor (he makes garden art) makes fiberglass molds for creating his statues. Would it be possible to overlay a few pieces of fiberglass over the cracked area as a temp fix? Any other suggestions?