Been running tubeless without incident for the last 2 years. 355 rims and Stans fluid. Noticed the back tyre was flat so pumped it up.
The air leaks out from around the base of the valve. Not aware of anything having knocked it but it won't reseal.
It is so long since I last did anything to the wheels I have forgotton if there is anything special I have to do to get the valve to seal against the rim?
WCA is it a JRA removeable core one or a mavic type one piece type? Sure it's not Stans guncking up removeable bit and holding open? I replace those (the cores every 18months or so).
If it's by rim all mine for last 4 years or so have just pushed through from inside and tightened up by screwing ring and the little oblong rubber bit does the trick (mavic ust rims)
computer did a 2nd post so edited down. Good luck with it
I had a JRA one that did that all the time, it seemed to seal itself OK after leaking but every time it was touched it would leak again - I swapped to ghetto
Mine does this too, I've even tried a new valve to no avail 🙁
The valves on my Roval Traversee's did that to, ended up switching to Stan's rim strips as the valves are part of the strip so no chance of leaking (ghetto would have the same result).
Are 355s UST?
If yes, just get one of these http://www.chainreactioncycles.com/Models.aspx?ModelID=17697
It is by the rim. I will check if DezBs su^ggestion works
They are not 'UST' as such, you need the specific valve:
http://www.freeborn.co.uk/shop/components/tubeless-conversion-kits/289-stans-notubes-olympic-valve-stem
On this page you can see they have three different valves for various tubeless wheels:
http://www.freeborn.co.uk/shop/stans-notubes/