Retro Valve venting out back

[need4reebs]

is their a way to visibly tell a newer piston from a older piston? would be great to this info please? thanks.

[robertreed711]

Wow, I didn't expect this to cause so much of a discussion. Just a little update, I opened up the valve and removed the piston again. I replaced the o-ring and tried to clean inside the small hole and reassembled the valve. I've aired it up a few times and it have not vented out the back of the valve yet. I will keep an eye on it and know that if it happens again it's time to order a new piston.

Thanks again for everyone's input.