Thread size for the puller is M6, 1.0 pitch. Another "while you're in there" job might be valve guide seals. Would add 2 or 3 hours but could be well worth it. If you do the seals, order the cam oiler tubes and connectors, as they may not survive the changing of the seals. Good luck

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Earl McLain
'02 C230 Kompressor
'89 560 SEL "Frau BlueCar" (retired April 2004)