Step 3 · Remove the Old Expansion Tank
With a bucket positioned underneath to catch water, firmly grip the old expansion tank with one hand to support its full weight. Use a large pipe wrench or a pair of channel-lock pliers on the metal fitting at the base of the tank. Apply steady pressure counter-clockwise to break the seal. Once it's loosened, you should be able to continue unscrewing it by hand. As you remove it, tilt it carefully to drain the remaining water into the bucket. Be aware that a failed tank can be completely full of water and surprisingly heavy.