Olympia Cremina SL Lever Mechanism "Catching"

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mcontraveos

#1: Post by mcontraveos »

Hello everyone,

Perhaps I need to file this under "nothing to worry about"..

I have a 4-month old Cremina SL. After pulling a round of shots, I flush the group to clean it out. On the lever upstroke, the mechanism feels like it "catches", roughly when the lever is at 90° to the grouphead. It feels like there's some small detent in the group cylinder at that position. This is only on the upstroke.

This started within a month of using the Cremina. I consulted with Cerini and sent the group in for service. When it returned, the lever upstroke was completely fluid - no catching whatsoever. Cerini said he found nothing of interest when servicing the group. Coffee also looked and tasted better, and the crema was more pronounced and longer-lasting; no idea if that's related.

About a month after service, now, and the group is "catching" again. Shots from new beans are thin and lacking in head/crema, possibly unrelated to the issue.

Any thoughts on what this might be? Is this indeed anything to worry about?

Many thanks,
MC

Sw1ssdude

#2: Post by Sw1ssdude »

I just serviced the group of one of my Olympia clubs, they have the same group as the SL. this time it only required silicone grease, as the seals are still fresh.

first time i serviced the group i noticed that part of the middle seal lip was ripped out by the edge of the bore where the brew water enters the group. the piece was missing, and the seal had something similar to a 'cleft lip'. this (but mostly the dry and rotten seals) had my group leaking from all possible places

check your seals and see if they are still intact. or if they ripped and catch in the bore

(servicing your group is not difficult, if you need help, hust let the HB-Forum know...)
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mcontraveos (original poster)

#3: Post by mcontraveos (original poster) »

Thanks. I had considered servicing the group myself, but was wary of the spring removal.
I reckon, though, that I could follow a procedure like this? Olympia Cremina SL Group Maintenance

I shared the concern about the shower screen becoming damaged, but perhaps that's not a thing either.

pcdawson
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#4: Post by pcdawson »

I would be very very careful servicing this group. It is easy to damage the group head if the c-clamp slips while taking tension out of the coil or reinserting the piston assembly after re-greasing the piston sleeve. It is also easy to damage the end of the piston sleeve and tear your piston gaskets if you don't have everything lined up properly when tightening the c clamp. Finally, the c clamp will damage the shower screen if the latter is not properly seated and completely flush with the piston head. You are probably way more technically savvy than me :) but in case you are not, I would consider removing the shower screen and gasket, having someone pull the lever down, sticking some Dow 111 on my finger and applying it to the inside of the cylinder. I'll never take my group head apart again and think this is a major design flaw with the SL. Why they didn't do something similar to the MCAL is a mystery to me.

pcdawson
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#5: Post by pcdawson »

I will add that both Cerini (USA) and Quality Coffee Systems (Canada) recommend sending the group to them for piston seal changes, etc. Cerini says this is only necessary every two years.

Sw1ssdude

#6: Post by Sw1ssdude »

Okay, i am not entirely sure why the guy in the link mounts the c-clamp over the shower screen for disassembly, otherwise he's doing a good job.

for disassembling (dammit! i've just done it and didnt take any pictures!) i take off the group, pop out the shower screen, and put a c-clamp (mote like an adjustable screw clamp) in place.

a very important detail is that the screw is almost fully extended! with a twist or two on the clamp the piston is pushed inwards (to take tension off the nut on the connecting rod), then the screw is slowly undone and the piston slides out as the spring extends. this is why the screw has to be as much extended as possible: if the screw bottoms out BEFORE the spring is fully loose,you're gonna have a bad time.

Assembly is just the steps above in reverse.

Shower screens for the old Olympias are very hard to find. i wonder if the ones from the Cremina SL would fit a Olympia Club group...
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pcdawson
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#7: Post by pcdawson »

Swissdude, how do you keep the piston seals from catching on the edge of the piston sleeve and tearing when tightening the c clamp during the reinstall?

mcontraveos (original poster)

#8: Post by mcontraveos (original poster) »

pcdawson wrote:I will add that both Cerini (USA) and Quality Coffee Systems (Canada) recommend sending the group to them for piston seal changes, etc. Cerini says this is only necessary every two years.
The first time I noticed this, the service I got from Cerini was great. Lever/piston action was night and day, and the coffee improved significantly. It does disturb me, however, that this will be the second time since May 2022 that I'll have had to send the group in for such service.

Were it not for noticing that the coffee were considerably better after the group came back from service, I'd think it's not such a big deal. Now, I'm starting to wonder if there's something else amiss.

pcdawson
Supporter ♡

#9: Post by pcdawson »

Can you share a video illustrating the problem?

Sw1ssdude

#10: Post by Sw1ssdude »

I insert the piston, and start compressing the spring with the c-clamp. As soon as the lip of the middle seal hits the edge of the bore and starts bulging, i use a blunt object (fingernail, edge of a spoon, letter opener) as a 'shoe horn', to guide the lip into the bore of the group. it will slip right in.

With a c-clamp, you can apply pressure exactly and position the piston very accurately. just be careful that the clamp does not slip off while you fiddle with the seal lip.

once the lip of the middle seal is in the bore, keep compressing the spring until the whole piston is in the bore. as soon as possible, screw on the nut on the piston rod (as a safety catch), but only if you can screw it on mutiple revolutions, dont just barely catch the tread.

once the piston is in, rotate the piston with the top nut to lign up the hole in the rod with the slot in the group, and assemble the lever fork. gently operate the lever a couple of times. if everything works as expected, mount the shower screen.

i service my groups twice or three times a year, mostly, thorough cleaning and regreaseing will do. i assume you could put the piston including the seals into the dishwasher for thorough degreaseing and de-griming... After every regreaseing, the lever operates very smooth.

it also helps to clean out the bore with 0000-steel wool and a mild soap (it wont scratch the brass) to get rid of the grease buildup at the end of the piston travel.
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