Just wanted to get feedback on whether I should replace the bottom seal on this piston (I'll replace both at the same time) from my Cremina. Was performing some group maintenance and I probably should have picked up on it before but my pulls were never dead center. When I looked at the puck I would have an indentation in the same spot pretty much every time.

The seals are still pliable and should last me a very long time but wondering if I should just go ahead and replace them so that I could get an even puck. Would this matter at all in terms of taste?

Take a look at the bottom seal where there is a small piece missing.

Thanks in advance.

I would swap top for bottom and see what it does.

If doing that, you might as well get a new set of seals so if one is damaged in the swap you've got a fallback.

Thanks fellas

I did swap out the bottom seal for a new one and I still get a dimple in the spent puck pretty much in the same place. Should have swapped out the top seal as well but it looked fine. The seals I'm using are from OE. Perhaps I'll try the olympia seals

I'm still searching for paper thin washers for the lateral fork play so when I find them I'll change the top seal.

Maybe I shouldn't be fussing with this. Does a uniform puck really mean anything?

Have to run out and get some beans at my local cafe. They only carry black cat but I'll take that any day over my wife's keurig

I wonder if your shower screen is clean or whether it's become clogged with something like excess lubricant applied to the cylinder or seals or with coffee. If you raise the lever with the portafilter removed, do you get an even shower of hot water? If not this may wet the coffee cake slower on one side. And yes, if you can get a centered pull you'll get better taste, much more evenly extracted.

I think I am going to try Olympia's piston seals to see if it cures the problem.

The water flow is uneven and when the lever is up at the top the water jets to one side. The pstat cycles between 0.8 and 0.9 bar. I like the OE seals. I've heard that they are easier to install and the Olympia seals are not as flexible.

I'll post some pics and hopefully a video.

Since the seals aren't stopping the flow of water at that point it seems your shower screen is partly blocked. If that's the case changing seals won't fix it.

Puck this morning


Gary

This morning I made a cup and no indentation on the puck.

I'll pop the screen but you are right about changing the seals without checking the screen. Only blockage might be some excess dow 111 that needs to be wiped off.

I did grind a tad finer and tamped a bit more so that probably eliminated the indentation in the puck.

There is a thread here somewhere that talks about the oem seals and oe's seals with no definitive conclusion other than for some machines oem seals solved the uneven flow problem if I read that correctly.

If the screen is clean and the water flow is not even I will try the olympia seals

Last night's puck

Must have been a stroke of luck this morning or the extra pressure on the tamp. Got back from work and pulled two shots with smaller divets but still there.

Going to pop the screen inspect it and get a video of flow.