Riviera leaking past piston seals - Page 4

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

#31: Post by miab »

Those pictures were to show you that bringing roller closer to center of shaft brings piston down. Not to replicate it (although that would work). You can accomplish some of this by using smaller roller.

I don't see how 2-3mm spacer would interfere with shower as the picture you posted a few comments ago shows you clearly have at least 2mm before piston comes to bottom of lip of group. Most shower screens even sit below this so you could have more room. If it does then find a deeper shower screen.

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cuppajoe (original poster)

#32: Post by cuppajoe (original poster) »

Yes, I understood the concept.

The clearance between the face of the piston and the end of the cylinder at rest is 1mm as measured with a depth gauge. The shower screen is not held in place by the portafilter gasket as in numerous machines, it clips on the end of the cylinder. I know of no manufacturer producing custom screens for this type of design, which is used on several vintage levers.

I'll reach out to Paul Pratt to see if he has any ideas.
David - LMWDP 448

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

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cuppajoe (original poster)

#33: Post by cuppajoe (original poster) »

Paul couldn't add anything new, so still on square one. I have a one group Riviera in for service, so have back burnered this one to work on it. I'll be measuring everything as I go along and if it does not leak when done it will give me a standard to work with.

I'd like to get my hands on a non spring unit for comparison purposes. It uses a shorter 2 seal piston and would be interested in seeing if the inlet port was in the same position.
David - LMWDP 448

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

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cuppajoe (original poster)

#34: Post by cuppajoe (original poster) »

The journey continues. I got the single group machine up and running with new seals for testing purposes, with no joy. Someone had put spacers on the piston rod and the piston face was just about flush with the end of the cylinder.

I noticed that the shower screen looked like a modified basket.

The piston did not contact the screen at rest, however it did hit the screen with a stock screen installed. The stock screen is on the right.

Unfortunately the thing still leaks at the piston.
David - LMWDP 448

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