Hi

I have just bought a series 3 fitted with a TD engine. It has been stood for 2 years. I got it running after I drained and flushed fuel system. Now there appears to be a preassure build up and I am getting a leak from the bleed pipe on top of fuel filter. I am no mechanic and it appears the fuel leaves the filter to pump, then goes to the 4 engine feeds and then back to the filter. Any suggestions as to why fuel would force by the bleed nut and drip out the bleed hose when its tight?? I am aware the preasure may be high but looking for possible cause / fix