Hi, you have to drop the tank, and there is a big plastic thing that includes flow and return pipes plus fuel gauge sender unit. The whole thing is held by a large threaded ring and rubber gasket. This was a pig to refit as it is a very tight fit and very coarse thread, I kept thinking it was cross threading and I resorted to using a strap wrench ! The seals in the snap connectors are also a possible source of air leaks. A word of caution, it is easy to snag delicate top of this unit on cross member as you raise tank into position ! Have fun. Bill.