I put my CMA 2 group back into use after its summer break. This time I relocated it to the basement and rather than putting the groups back together after the move downstairs, I wrapped them in plastic and stored the machine with the portafilters in place.

Today after reassembly, both groups showed piston seal failure. I changed both and one group still leaks which I think demonstrates failure of the inner sleeve seals. I will change them out and see what gives.

The seals are at least 2 years old and the sleeve seals more like 6.

Was this effect of natural history of rubber or did storing the beast with groups dismantled in my temperate basement hasten things?

6 year old sleeve seals??!!?

As the nurse said in Groundhog Day, "He was just old."

I would think. I recall someone saying in these pages that lever group inner seals take a long time to fail and I have generally done maintenance as needed rather than routinely. I don't use the machine in a cafe setting.

I will change seals in both groups since one seems to be failing. And soon pick up some of those intriguing Cafelat silicone ones.