Sorry about the pun, it's just too much caffeine in the system as usual. It has to go somewhere
Anyways: after a looong hiatus, I have finally gathered up the guts to fix the broken C-ring in the Strietman ES3 piston, using the spare parts graciously sent by Strietman himself. After removing three years (bleeerrhh) worth of oxide and salts from every copper and brass surface and changing the gaskets, the WS3 was finally put to the test again.
And I ran in to the same problem as just before the first c-ring breakdown: trapped air in the piston.
Have tried searching around for others with the same problem, but can't find any. Maybe I just used the wrong terms, or maybe I am indeed alone with this problem. I thought this would be the best place to find out.
This is what I do. Since I am used to the Caravel, and well acquainted with the feeling of doing a pull with trapped air in the piston, I started by pulling up the lever fast, expecting to hear the burbling sound of water rushing down the piston. It doesn't come, so I surmised this is the wrong way of going about it on the ES3 (as it is with the CT1, I guess), so I started pulling up slowly instead. But no matter how I do it, I keep getting air trapped. Sometimes I can get most of it out by knocking on the side of the machine or by doing small downward/wiggling movements of the lever, but almost every time as I start seeing drops forming on the bottom of the filter I also see - and hear - bubbles come out.
Is there anyone else that's had this problem? What did you do to avoid it? I thought the problem might have been build-up inside the piston, but not anymore, it's not there now after the mega cleaning session.
Edit: should add that this is ES3 #6, so it's one of the early ones. I used it for about 4 months before the C-ring broke (the early ES3 lock rings were made out of brass, the replacement is stainless steel and much more durable).