Hi all.

Just doing my first ever DIY service on a very recently acquired Gaggia Factory 106 and have a quick question regarding the installation of the new group gasket and dispersion screen - am itching to starting using it! The gasket that came off (almost dropped out, to be honest), which still looks good though replacing it as a routine measure because it has never been done before, is a fully round profile type, the new one, which was ordered as a compatible part for the Gaggia but is a La Pavoni new group model, has a round profile on one side and a flat profile on the other. Can anyone advise which way round the new gasket goes in? It seems to fit neatly with the round profile part against the curved lip of the screen (which would mean that the basket seals against the flat side of the gasket), though don't want to get it wrong. Any advice would be greatly appreciated, and I hope I explained it clearly.

I did search for this but apologies if I missed a multitude of answers, if the same question was asked before.

I'm sure there's a right and wrong way to install that, but I'm also curious about whether it makes a difference since the only portafilter gaskets I've seen were entirely round o-rings or entirely square gaskets. In either case you would tighten the portafilter against it and it should compress. BTW my best guess would be that the flat side faces down, or is it the other way around?

Added: I have seen portafilter gaskets that started round and flattened after being used, where the portafilter tightens against it and shapes the soft material. Is it leaking around the portafilter? If not is the group screen also coming loose? That can happen if you have a plastic piston that starts to loosen, turning on the threads on the piston rod.

I have a gasket like that on my Millennium, and agree with Gary, rounded side up and flat side down. To install it you can gently lock in a PF with no basket, then add the basket and lock it in good and tight. I rub on a very thin coat of dow 111 on that gasket, partly to make it easy to pop out the shower screen for periodic cleaning.

homeburrero wrote:I have a gasket like that on my Millennium, and agree with Gary, rounded side up and flat side down.

Well, we agree 50% of the time! I've never heard of this and wonder if the new gaskets are made that way or if this is a worn one.

Thanks for the replies. Gasket is a brand new one and fits perfectly, round side up. I have finished the rebuild now (thanks also to the excellent youtube videos showing the strip down and rebuild from orphanespresso) and have boiled water in it and flushed the machine out a few times following the descale on the boiler. Looking forward to the first coffee from it in the morning.

Thanks again!

Pulled my first couple through this morning and initial results are good - much practicing to do, I think. Still have the very slight drip from the steam wand (on the wand side) that was there before the service so will have to have another look at that. Have read about the use of Barkeepers Friend on the internals so will work out how best to get it in there and give it a careful try. I replaced the steam tap shaft and rubber washer as part of the rebuild (original was pitted/missing chrome at the tip/contact end and had hoped that just changing it would cure the drip: no such luck. Overall though, am very pleased with purchase of the slightly faulty 106 and will now let go of my 105.

drgary wrote:Well, we agree 50% of the time! I've never heard of this and wonder if the new gaskets are made that way or if this is a worn one.

Flat on one side and round on the other is a factory original, with the round going up as it "cups" the shower screen. Ones that are perfectly round are nothing more than O-rings that some vendors were selling as a less expensive alternative to an original.

One thing I noticed after rebuilding the machine and using it for the first time, is that I was getting significant channeling (to the right side as you stand in front of it) despite my roast/grind/tamp being the same as with my 105. Scratching my head as to why whilst stood in front of the machine, I noticed that the angle of the group was off and was tipped over to the right (hence the channeling). I had simply rebuilt it so that the 'diamond' on the boiler matched the edges exactly of the 'diamond' on the group, if you rubbed your finger over the join, but it seems that the two don't match exactly. The boiler is vertical so at least it isn't that the machine skewed over, its just it isn't a perfect match as it is on my 105.

uscfroadie wrote:Flat on one side and round on the other is a factory original, with the round going up as it "cups" the shower screen. Ones that are perfectly round are nothing more than O-rings that some vendors were selling as a less expensive alternative to an original.

Good info. Thanks!