Hello, I am a new member but have perused this site for some time now. Thank you to everyone who has unknowingly provided me with valuable tips in the past. I have been making espresso for many years but just started on a new MCAL lever machine a year ago, -again thanks for giving me the confidence to use one. I enjoy servicing my machine and have noticed that the group gaskets slide back into the group much easier now than they did a year ago when new. No issues at all with machine operation yet, just wondered what people thought about how often the group gaskets should be changed?

Unless you use VERY good water, be sure to remove the piston assembly every few weeks to check for corrosion, chloride in water can concentrate in the group and initiate chloride catalysed oxidation of the metal (the so called bronze disease, and brass is really Zn bronze, and very subject to it.) The top of the piston is open to the air unlike many other designs. This makes it unusually sensitive to water that is polluted with salts. The instructions with my MCAL came with a disclaimer for bad water damage.

When piston seals fail water will emerge from the small hole on the back side of the group about a centimetre or so below the flare for the piston assembly attachment. When placing the piston back into the group bore after disassembling it, be careful not to damage the seals. The seals seem fairly long lived. As time goes on the cylinder walls will become smoother when used with decent water.

I distill and remineralize my own water, so no issue there. Thanks for the tip about the little hole in back of the group. Never think to look back there.

Answering my own post here for anyone interested to know. I went ahead and changed the ELektra MCAL group seals (not portafilter gasket) and it made a big difference. Most noticeably I was getting coffee fines in the boiler. Can only assume this was from the loose seals(?) that had no noticable effects except a small amount of water in the cylinder when removing the spring assembly. The last couple of months with the old seals I also noticed that my once a month lube interval wasn't often enough for smooth action anymore. Works like new again now. Used everyday for a year, the seals had about 300 hours of use on them. I assume that keeping the machine on for a minimum amount of time would prolong length of days between change intervals?
Also spent way too much time learning to take apart, clean and descale the Mater pstat which once again works like new. I suspect some fines had made their way into it. I question how often people seem to complain about and replace the Mater when all mine really needed was detailed maintenance. It certainly seems like it would be very suspect to scale build up and it acted completely wonky when not operating correctly.