Is the fact that the Franchisee's "Service Director" can have the Shop Foreman show you the you the "Klann" (Gedore division that manufactures the "Tool Kit")
Tool Kit! AND the Technician's Attendance Certification for the Instruction
provided by Klann on the PROPER operation of the Tools.
Link to Video of Tools in use:
CDI broken glowplug repair wo/thread repair kit - YouTube
They,(Klann),make different versions of the tools:
with and without thread repair.
Exemplar of why to be SO CAUTIOUS about letting ANYONE without the Tool Kit
Touch your 606's G.P.s :
Removing a broke glow plug from 606 engine head | Mercedes-Benz Club of America
Heck,If I had this Tool Kit I'd let my 3 year old Grand Niece try and R+R OM606 G.P. s with Safety Glasses and a Ball Peen Hammer WITH NO WORRIES!