How To Repair Radiator Air Vent Threads

In this video, This Old House plumbing and heating contractor Richard Trethewey and host Kevin O’Connor cut threads for a new radiator air vent.

Project details

Enlarge the existing air-vent hole in the radiator with a 7/16-inch-diameter high-speed steel drill bit.
Put a ¼-inch tapered tap onto a ratchet wrench and cut new threads into the 7/16-inch hole.
Spread pipe dope onto the threads of a ⅛-inch to ¼-inch bushing, then thread the bushing into the hole and tighten with a ratchet wrench.
Apply very little pipe dope to the threads on the air vent and thread the vent into the bushing; hand-tighten the vent until it’s in an upright position.

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