Did you ever find out what size the o ring was cheersthanks got it sorted, more by luck rather than experience
Yours quote a different size to those quoted in post #5. Wonder what the Alko specified size is ?Recently replaced both of mine, bought them off Ebay, nowhere near the ridiculous price Alko are asking for them think they were about £2.00 for 4 free delivery too. Size is 9mm x 2mm . see link below
I have hundreds of O rings. None are precisely the same as the Al-ko ones. The Oem are expensive . But they last years , They are fitted to a critical safety item! Please please just buy the genuine Al-ko O rings. A no brainer👍