I have a recurring problem with pump maintenance on my 0-ring sealed pumps (currently w/ road morphG, but also w/ other pumps). After a year or two of use (mainly being carried around), my pumps lose efficiency or quit working. They've been thoroughly cleaned and inspected and I can see nothing wrong. After a good clean and lube they get better but never reclaim their new efficiency. After a recent cleaning, I lubed the pump with some high quality turbine oil, which prevented it from working at all. My conclusion was that the o-ring has to generate enough friction to seat itself. I replaced the turbine oil with some sticky chainsaw bar-lube, which made the pump work, but not at its new efficiency.
Does anyone have a secret for keeping pumps at top efficiency over the long term?