Riviera Two Group piston seal problem

Equipment doesn't work? Troubleshooting? If you're handy, members can help.
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cuppajoe

#1: Post by cuppajoe »

Greetings all -

It's been awhile since I've frequented the boards, apologies.

I'm working on a 2 group Riviera that is driving me nuts. It is leaking water past the piston seals when it starts coming up to pressure. I've replaced the seals, wrapped teflon tape around the piston slots, replaced the seals with the new style larger seals, all to no avail.

Hoping someone might have a solution.
David - LMWDP 448

My coffee wasn't strong enough to defend itself - Tom Waits

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cuppajoe (original poster)

#2: Post by cuppajoe (original poster) »

Here's a couple of shots showing the seals in relation to the piston. Testing fit without the spring seemed to confirm a tight seal and smooth operation.

Any help appreciated.

David - LMWDP 448

My coffee wasn't strong enough to defend itself - Tom Waits

Flair Espresso: handcrafted espresso. cafe-quality shots, anytime, anywhere
Sponsored by Flair Espresso
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IamOiman
Team HB

#3: Post by IamOiman »

Got a pic of the piston sleeves that the seals rest against? That is the first thing I think of outside of the pistons being compromised if the seals are not the issue
-Ryan
Using a spice grinder violates the Geneva Convention
LMWDP #612

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cuppajoe (original poster)

#4: Post by cuppajoe (original poster) »

Thanks for the reply.

When the teflon trick didn't work, my first thought was the bores had been damaged. They do look scuffed and the original seals had been worn down to the pistons. I'll try and get a pic.
David - LMWDP 448

My coffee wasn't strong enough to defend itself - Tom Waits

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cuppajoe (original poster)

#5: Post by cuppajoe (original poster) »

Here's what the group bore looks like. The divots in the wall seem to be above the top seal. The water inlet hole is about at the middle of the center seal when the piston is at rest.

Both groups have this same problem and the pistons are in good condition.

David - LMWDP 448

My coffee wasn't strong enough to defend itself - Tom Waits

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drgary
Team HB

#6: Post by drgary »

Here is a wild guess. Is the top seal (the lowest one in the photo above) installed in the wrong direction? Otherwise the damage in the piston bores do look suspect.

Gary
LMWDP#308

What I WOULD do for a good cup of coffee!

RobAnybody

#7: Post by RobAnybody »

drgary wrote:Here is a wild guess. Is the top seal (the lowest one in the photo above) installed in the wrong direction?
No, the seal orientation is as it should be

the scratches look weird indeed but they are quite high up in the group.
Have you checked if you could feel any rough patches lower down in the group bore? Sometimes these things can be easier felt than seen.
cheers,
Rob
LMWDP #647

ECM Manufacture: @ecmespresso #weliveespresso
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yakster
Supporter ♡

#8: Post by yakster »

Have you lubed the seals with Dow 111? It's leaking out the bottom of the group, not the top?
-Chris

LMWDP # 272

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drgary
Team HB

#9: Post by drgary »

Thanks, Rob. So much for that theory!

If it is leaking out of the bottom of the group, have the lugs worn on the portafilters so they are not sealing well? I ran into that problem when servicing a Zacconi Baby.
Gary
LMWDP#308

What I WOULD do for a good cup of coffee!

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cuppajoe (original poster)

#10: Post by cuppajoe (original poster) »

Thanks for the input folks.

It leaks past the seals from the bottom. Seals and bore were lubed with food grade silicon.

I can feel some ridges, and upon closer inspection can see some vertical gouges in the bore. Other than descaling and cleaning, I only polished the bore with bronze wool. It appeared the owner had never performed maintenance and continued to use the machine well after it started having problems. I found coffee residue above every seal and the shower screen was completely choked. It had also had repair attempts done before it landed in my lap. The wiring was so bad I couldn't diagnose in original state.

I took another photo trying to better show the condition of the bore where the piston moves.
David - LMWDP 448

My coffee wasn't strong enough to defend itself - Tom Waits