John, if your 190E water pump is like the one in a 1991 300CE a 6mm allen wrench and a 13mm Craftsman socket with a universal joint plus several extensions will handle the job. For the allen bolt be sure to properly align the allen wrench, apply pressure with one hand, and hit the end of the allen wrench with a 5lb. hammer to break the bolt loose. For the other 3 hex head bolts use the 13mm universal joint socket and a breaker bar w/extensions, as required, to break the bolts loose. The water pump replacement takes patience and persistence ... whatever you do make sure not to damage the allen bolt or the hex heads. Insert the water pump/head O-ring into the pump recess and smear some grease over it to hold the O-ring in place when installing the new water pump.

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Fred Hoelzle