Step 6 · Install the New Angle Stop
Take your new quarter-turn angle stop and disassemble it. Slide the new compression nut onto the copper pipe first, ensuring the threads face outwards (towards you). Next, slide the new brass ferrule onto the pipe, with its tapered end facing the end of the pipe. Push the body of the new valve onto the pipe until it rests snugly against the ferrule. Slide the compression nut up to the valve body and hand-tighten it. Now, use your two wrenches again: one to hold the valve body still, and the other to tighten the compression nut. Tighten the nut one-half to three-quarters of a turn past hand-tight. Do not over-tighten.