fuel tank vacuum

[malsgoing130]

Hi All,
Ive got a 130 with a long ranger long range tank fitted and had an weird experience while trying to put fuel in. There was such a big vaccuum in the tank that I almost could not get the cap off. The question is where do the tanks breath from? please help
Cheers Mal

[robdav]

I fitted one a little while ago. My understanding is that they breath through the filler cap.
You do not want a vacuum in the tank!.
I had an experience several years ago where the breather pipe to my underfloor tank got pinched off. The resulting vacuum partially collapsed the main tank. It also caused the fuel lifter diaphram to fail which somehow, perhaps in combination with the vacuum created (I still don't know how), caused the engine to over rev and self destruct. The fuel flow could not be stopped. This experience set me back $13,000.
MAKE SURE IT CAN BREATH!!!!![/B][/B][/B][/B]