Tensioner rail, remove.

Remove timing chain
Partially unscrew bolt on right front of cam carrier, so that it no longer covers the pivot shaft for the tensioner rail.
Install BMW special tools 11 3 04 , 11 3 042 and 11 3 062. Or a slide hammer or puller and remove the shaft. Alternatively, you can thread an 8x1.25 bolt into the shaft and pull while rotating the shaft.
Installation :
Replace and lubricate O ring with engine oil.

E30 M3 Repair Manual V2.7. Copyright Š1999-2001 Koala Motorsport & Brett Anderson