Anyone with a vehicle knows that fuel is really rather flammable. This is why you do not smoke at a fuel station. Anyone owning or driving an old vehicle should be equally careful with the state of the fuel “line”.
From the tank to the engine, the fuel is permanently sitting in metal pipe, plastic pipe and rubber pipe. There is no off switch, so if this ruptures, you are dumping the entire contents onto the ground, so from a financial point of view it is a sensible idea to ensure this is all in good order. From a heartache perspective, it is imperative as well.
You do not want your pride and joy catching fire due to a leaking pipe spraying fuel onto something very hot in the engine bay.
Taking the Type 1 engine as an example, there are multiple systems in place as primitive fuel emissions systems.
The U shaped pipe number 9 is the one that you can see on the roof of the engine bay in a Bay window just above the number plate.
Red pipe numbered 24 needs a long arm and can be reached by putting your left hand up past the rear light cluster up the side of the bus and is quite a tricky little one to replace. If you can smell fuel always, especially if you sniff the air intake on the left side, that is often missing or perished.
The ones next to the fuel tank in the picture by green 24 are all behind the fuel tank firewall and need the engine to be removed.
My local VW mechanic recommends replacing all of the rubber components at least every 3 years and last time , we found that blue 24 in the middle of the picture on the pipe heading to the right was actually disconnected, causing fuel to spill over the top of the tank when turning right with a full tank! We had a clean section of tank and a lucky escape.
In summary. Ensure that your fuel system is inspected regularly by a competent mechanic and relevant parts are changed. The new fuels have either Biodiesel or Ethanol in them, which are not good on modern rubber pipes.