[chris turner]

Just fitted a new 500 litre flat wydale tank in the van. Got home today and the tank had collapsed in on itself!
Had to use a hammer to get the lid off as the vacuum had sucked it in tight. Also caused the hose coming from tank to split
The lid has no vent in it, and has a big rubber o ring to seal it closed. It doesn't leak when full, which is great, but how do I stop the vacuum forming and collapsing the tank!

[matthewprice]

Had same on Ibc tank drilled a 4mm hole in lid an hasn't happened since

[Smudger]

Drill a hole

Darran

[Dave Willis]

Drill hole and fit a length of ro pipe - bit like a motorcycle trials bike petrol tank.

[chris turner]

Realised on the underside of the lid there's a cone piece that petrudes out with a hole in the middle. Just drilled a 4mm hole in there so hopefully sorts it. Guess that's what its there for as doesn't seem to have any other purpose! Just didn't want to be making holes without advice first..
Last tank had a vented lid so never had these type of issues!
Thanks all..

[Mike #1]

I thought vented lids had been standard for a few years now .

[AuRavelling79]

Put a bit of hose in the drilled hole about six inches long and it will stop water squirting out when you brake hard.