fuel filter O ring question

[Granville]

While driving up the motorway the other day I noticed white smoke (diesel fuel running onto the exhaust) behind the surf, pulled over and found the rubber O ring at the bottom of the fuel filter had pushed out of the side again.
The O ring is the one at the bottom of the filter; this has happened twice now and wondered if anyone else had had this problem? Both times it’s been on long motorway runs. It’s as if the O ring expands and pushes its self out of the gap between the filter and the plastic bottom bit with the water tap.
Any ideas why this is happening?

[Maverick]

The short answer is no, and I do the filter changes myself which leaves pleanty of opertunity for things to go wrong.
What filters are you using, cause Milners always suply a new O ring with the filter.

[Granville]

The short answer is no, and I do the filter changes myself which leaves pleanty of opertunity for things to go wrong.
What filters are you using, cause Milners always suply a new O ring with the filter.

Been using the Milner filters (as they are only just up the road) and new O ring each time. the only thing I can think of is that I could be overtightening it, then when it gets warm on a good run it just has no room to expand. Had a good look at the plastic bottom bit and it looks nice and flat so going to put it down to my big fat fingers.