That pipe will produce petrol fumes especially if the tank is full in hot weather. The rest of the pipework is buried behind the firewall and connected to the tank. There are rubber splices appx 2 inches long at various points. This is an extreme fire hazard as they are very possibly in there from when the van was built. The only way to replace these is with the engine out and with the firewall removed. Replacing these hoses is a few quid but the value of your van is priceless.