Sealey Reverse Action Spark Plug Thread Chaser

The Sealey Reverse Action Spark Plug Thread Chaser M14 (Model No. MS003) is engineered for repairing M14 threaded spark plug holes, the most common thread size in modern petrol engines. This makes it an indispensable tool for any professional automotive workshop or well-equipped home garage. The M14 variant utilises the advanced reverse action design that distinguishes this tool from conventional thread restorers. By passing through the plug thread into the combustion chamber and expanding to engage the inner, undamaged threads first, it guarantees accurate alignment and reliable restoration results. Traditional thread chasers often fail because they cannot ensure proper alignment between restored and existing threads. Thread size identification is straightforward: for Denso, NGK and Bosch spark plugs, check the first letter(s) of the plug code, whilst Champion brand plugs use the second letter(s) to indicate thread size.