Don't know about the C280, but many Asian models have a fuel flow fuse(controls fuel pump) that you first pull out. You then start the car and let it run until it dies out. This relieves pressure in fuel lines so that when you disconnect the fuel line from the fuel filter, your face isn't sprayed. You'd be amazed at the pressure that can build up in a fuel line.

I don't know what the ramifications are for pulling the ground strap off the battery on your car, but I always remove mine first when changing out the fuel filter.

Gas + a spark and you and your car are gone.

__________________
Mike Murrell
1991 300-SEL - Model 126
M103 - SOHC
"Fräulein"