I'm actually looking for advice on replacing the waterpump on a 307d motorhome I own in the UK. Jim Smith indicated that the water pump is the same as the one on a 300sd so I'm looking for someone with experience replacing one of those. The one on the 307d (which has a 616 engine) is unlike the 616 in the 240d in that the fan does not attach to the pump with four bolts but is attached with one large central bolt which threads directly into the center of the water pump shaft. What I need to know, is how easy is it to access and remove this central bolt? Can it be done with the radiator in place? Is there enough room to back out the bolt all the way and what kind of wrench is best to use for that task. Is it fairly easy to drop a pin down through the top weep hole and through the hole in the pump shaft to hold the whole assembly while the bolt is removed?