Air bubbles in fuel filter

[Remyd]

Hi all,

Whilst I was looking at the engine running in my GT this Morning, I noticed that there was some air bubbles coming up in the fuel filter. The said filter was also moving when the air bubbles were hitting it. After doing a quick search on the web, I read that it could be due to a leak somewhere in the fuel system. Would this be the case and does it affect the performance of the car?

Remy

[Bumpa]

I've never seen a transparent fuel filter that didn't have air in it. They are never full up in my experience, but that doesn't mean there's a leak. Surely if you had a leak you would be able to smell it?

[Remyd]

The air bubbles are coming from the inlet pipe, the one coming from the pump, which I have never seen before. The filter always has air in it but not bubbling from the inlet pipe.
I have had worked done on the gearbox recently, which required the engine being taken out. I will check that the pipe has been put back in tight enough first before i check the rest of the line.
A few weeks ago, I got stuck in traffic for a while, when I got going again, the MG was very sluggish, not as fast as usual and shuddering so I am wondering if the air bubbles had something to do with it.
Here's a few pictures of it.

[Mrbenn]

That fuel doesn't look great to me. Shouldn't it be a lot clearer than that?

[Jim Gibson]

It is common, but not always the case, that the filter has some air in it.

But air bubbles appearing suggests air leaking in, not fuel leaking out.
Check connections of pipes and hose from the tank to the pump.
Also check condition of the metal pipe between the tank and pump. Pin holes from corrosion allow the pump to draw in air.
When standing with the pump off the pipe doesn't necessarily leak fuel out. Because there is no significant pressure &/or the effect of the fuel's surface tension I guess.