In my readings to find a pump for the 850,,,I read several feedbacks about the problems people have had which led them to either buying a new pump,,or new seals for the pump.
The symptoms described was exactly what I had experienced,,,,,in the summer: pumps up to a certain pressure and the pump handle locks mid stroke from a seeming vacuum / pressure lock where I couldn't pull the handle up nor push it down. I had to bleed the air off and start over and come to the same lock up. Temperature was above 90 degrees,,,and humid ( I live in FL).
My experience leads me to believe that those problems are simply atmospheric in origin and are limitations of probably most hand pumps. My older Air Force pump which was locking up in the summer works just as perfectly as my new Benjamin pump. The difference being that the temp on the floor this time of year is in the 40's and right now when I just pumped the humidity was below 40%.
So when summer comes around, I'm only going to pump up in the morning when it is still cool. Of course the problem probably could be resolved if I had Air Conditioning and kept at least one room in the house at a comfortable temp - but I don't. I'd rather have PCP's than creature comforts. You know, everybody has their priorities.
