Installing A Shower Drain Assembly
If you are replacing a fiberglass shower pan adding the drain connection is the most important part. If it’s not done correctly, you get a leak and the resulting water damage. The drain connection looks very intimidating, but it is actually very common sense.
First off, spend a few extra dollars and buy a brass drain connection. Plastic is cheaper but don’t use it. Use plumbers putty under the lip of the drain and tighten the nut underneath the shower pan. The putty should ooze out.
What you will be looking at is the drain pipe in the middle of a hole in your floor. The pipe should be at about floor level, but dry fit everything before you make any cuts. The drain assembly will fit over and around the drain pipe.
At the bottom of the assembly is a lip. With the assembly over the lip, place the neoprene washer around the pipe. This will be a snug fit, so you may need a wooden paint stir stick to fully seat the washer against the lip at the bottom of the assembly. A little liquid soap can help as it acts as a lubricant to slide it on down.
Insert the compressing ring and start tightening it. This threads onto the inside of the drain assembly and compresses the washer against both the outside of the drain pipe and the inside of the drain assembly. This is what prevents leaks. The compression ring has notches in the top of it to accept a small metal key. The key drops into the notches and you can start turning it. Once it becomes too difficult with your fingers, you can slide a screwdriver into the slot in the middle of the key and continue turning.
Finally, you can snap the strainer into place.