More than once, the hex-drive of an extremely seized Glow Plug will break off during the removing-process.
The central contact of the glow plug prevents the drive hexagon from being removed as it´s attached to the Glow Plug body. With these tool set, in a few steps, the central contact will be removed, a screw-on or hammer-in drill sleeve installed, and the glow plug will be drilled out by a guided drilling-system.The Glow Plugs on OM651 engine are very hard to reach, therefor, and for the safety of the working-process, a guided drilling system is essential.

Working-steps:
> Removing the central electrode
> Drilling out the Glow Plug thread
> Extracting the Glow Plug
> Cleaning the Glow Plug hole with brushes
> Recutting the Glow Plug thread in the cylinder head