Hi. As a newbie I have checked most posts so hope I'm not repeating an earlier query. My 5 year old Butterfly with a single E61 group has been in storage for about a year. It had been cleaned with head cleaner before it went out to the shelf. I have left it hot for several days now and cleaned and back flushed a couple of times but it still leaks on - quite a steady flow actually - after I finish pulling a shot. The coffee tastes great! Following advice from some other posts I have stripped the E61 unit but can't see any obvious wear. I suspect a spring - or springs may be weakened. Has anyone any idea which area is most likely to be at fault? The group drain valve, infusion valve, or brew valve assembly. The lever action is smooth and it neither drops nor moves up by itself but I haven't yet got lubricant for the cams - that's on the way!
Thank goodness I have my two group machine in great order - I've learnt heaps just reading these posts.
Best wishes for the festive season to all from sunny New Zealand!

See the diagram in Constant dripping from E61 grouphead. If the group is dripping from the bottom, the upper valve isn't sealing, either because the gasket it worn or the valve is sticking.