air bubbles in fuel line

[Red Ed]

There are air bubbles in the clear fuel line running from the filter to the pump on my 1.9TDi. I serviced it today by removing the control valve, taking the unit out of its housing and drawing off some fuel from the plastic drain screw on the bottom.

I put everything back together and started the engine and there were still a lot of air bubbles visible. I revved the engine a few times and they didn't go away.

Checked the Haynes manual and he says there shouldn't be any bubbles but doesn't say what causes it or how to remedy it. The car seems to be running fine. Does anybody have any advice?

[Crasher]

Quite normal, nothing to worry about.

[Red Ed]

Good!