put the hood in the full vertical position by using the red button on the hood strut.

for the C-class, check how the cabin filter housing plastic edges at the bottom/back lock into the housing before unclipping - it is easy to misalign when reinstalling. When reinstalled the filter housing is solidly in place and can not be hinged upward.


place a thick protective cover on the fender because the battery is heavy and exits close to the painted fender.

make sure the key is not in the ignition

disconnect the NEGATIVE terminal first then the POSITIVE, I think it's a 10mm socket, a ratchet works better then wrench. It is the cable connections at the battery that lock the battery down in the tray.

from the factory there is a vent tube coming off the battery, I think presently dealers are NOT replacing the vent hose because it isn't necessary, so you may not have the vent hose, if you do notice it then reattach when reinstalling.

when the battery is out clean and inspect the battery tray for moisture, acid leakage or anything unusual.

install new battery carefully and have the cables lodged out of the way. be careful to avoid scratching the fender with belt buckle, tools or new battery.

when restarting car there will probably be an ESP malfunction, simple drive car and turn the steering wheel completely form lock to lock. May need to synchronize windows and sunroof by holding the switches in the first detent for a few seconds.