XSeries-forum

The air pump has an air filter for incoming air ,which could be blocked or the O-ring has not sealed as it is 11 years old and O- rings tend to not re-seal properly .
Some silcone gasket sealer might work if left to cure long enough .

Oh really! I wish I had to time to fix it now but I need the car back on road so I've just bought a pump off eBay from a 2007 750i with 36k miles for £140 which I didn't was too bad especially as its low milage so hopefully wouldn't have had much use.

I will keep my old pump anyway as a spare and will take a look at the air filter and apply some gasket sealant to see if I can restore it to working order again when I'm bored on a rainy day.

Thanks Again!
James