After removing the mud shield (fitted some arch flares) on the off side rear, I've noticed an 8mm hard black pipe which has a pre-formed bend at the end and is clipped to the fuel filler pipe. It then dissappears over the top of the tank on my 300Tdi.
I know its not an axle breather as I've replaced these with raised ones and I also know its not the tank breather as there is a seperate pipe for this.
As I'm only curios and dont wish to remove the tank to follow the pipe anyone know what this is for as I've invested a bit of money in raised breathers, snorkel etc and will be pi**ed off if I bust something when wading!