I have a single handle Gerber tub/shower faucet. I cannot figure out how to remove the spout. I cannot find any set screw through the access hole at the bottom of the spout. I can twist the spout about 1/6 of a turn, but still cannot see how it is held onto the stem. Should/could I twist harder? Water is leaking between the spout and the shower wall, traveling along the stem pipe, down the supply line, and onto the ceiling below.