The Powerbuilt Tools Back-Tap tool from Alltrade Tools offers a patented collapsible design allowing users to place the tool through the spark plug hole and into the combustion chamber. A mandrel is then drawn back, expanding the tool's threaded area and threading into the clean threads at the bottom of the spark plug hole. The Back-Tap repairs the damaged threads as it is drawn up through the spark plug hole, bringing debris and metal filings with it.
