carbon ring seal

Just replaced both carbon rings in my skis (done this before and know how to do it correctly) however I put one of them in the water and with out turning the ski on it just started leaking right in between the stainless steel ring and carbon ring. The other ski doesn’t do this. I was wondering...

Replaced the carbon ring along with the bellow, steel ring, and new half moon clip The half moon won't recede into the steel ring? No matter how hard I try it won't go inside The two pieces came together in a kit, I would think they would fit each other I'm almost certain it's not supposed to...

How can you tell when it's time to change the carbon ring on the pump seal? Ok obviously if water is flooding in thru the seal then it's probably way PAST time to change it... but what are the symptoms of a carbon ring wearing out otherwise? How long do they generally last? Mine's at 74 hrs so...