I have a 2008 1.3 Copen that over the past 18 months that has had an intermittent fuel leak where the fuel sender/pump unit bolts into the tank. Having replaced the rubber seal twice and the sender bracket and bolts purchased from a ex Daihatsu dealership, with little or no solution to the problem. Out of sheer frustration I took the rubber seal and bracket to a small O Ring specialist company (Allseals) in Norwich, upon inspecting the manufacturers square rubber seal. I was horrified to be told that the seal wasn't even petrol resistant! (Well done Daihatsu!). A replacement O Ring made from Viton 75 was found and ordered at the total cost of £14.40 inc vat. Allseals delivered on there promise, I collected it the next day. Upon fitting the new seal not only does it fit the sender body tighter but fills the gap between the tank and the fuel sender bracket better than the original seal, therefore preventing any further leaks of petrol and vapors. If you're experiencing the same problems as I have, try this solution!. I recommend using Allseals (East Anglia) Ltd. Tel 01603 401218 and quote part number RM 1043-57 VITON 75.