Step 3 · Remove the Old Angle Stop
This step requires two wrenches to prevent damaging the pipe. Place one adjustable wrench or a pair of channel-lock pliers on the body of the angle stop to hold it steady. This counter-acts the twisting force. Place a second adjustable wrench on the large compression nut located where the valve meets the copper pipe coming out of the wall (the stub-out). Turn this nut counter-clockwise. It may be tight from years of compression and corrosion. Once you break it loose, you should be able to unscrew it the rest of the way. Pull the old valve straight off the pipe.