sender unit has a bolt through it and have had these rotting,leaving a hole in the tank unit,also check the o/s of the tank near the filler pipe,there is a flange on the chassis which was bad for rubbing through the tank,the tank would have to be replaced and while it is off flatten this bit of chassis with a hammer,just a couple of ideas,it may be pipes/other problems,good luck
cdc, October 2010
