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chimpsinties

Gaggia Classic leaking around group seal

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I've had my trusty Classic for about 10 years now.

 

It gets a regular back flush (about once a month) and a descale every now and again. I live in a soft water area so there never an issue with limescale build up anyway.

 

I've changed the portafilter seal many times over the years and moved away from the OEM rubber seal years ago in preference for silicon seals from an E61 as they're the same size. I get the blue ones for a few quid each. I've never had any problem with these in the past.

 

Recently I started getting water leak from around the top of the portafilter when I make a shot. My first thought was change the seal and last time I'd actually bought two for this reason so I had a spare. I swapped it out and it worked ok for a few shots then started leaking again. I asked the seller if he'd had any other people complain about these seals being faulty and he just said I shouldn't be using them and should stick with OEM. So I bought a couple of OEM rubber seals, fitted one and again, it sorted the issue for a day or two then it started leaking again. It's only a few drops that sadly tend to drip down into my cup. I've had it all to bits multiple times now to see if I've missed something and made sure everything was nice a clean but can't seem to solve it.

 

Someone has suggested trying a new portafilter itself but I've actually got 2, an original double spout which I've barely used and a naked portafilter which is my go to. It makes me think there's not an issue with that as I've tried both and it happens regardless.

 

Have I missed anything. I have been toying with the idea of an upgrade anyway and maybe the Classic has just reached the end of it's very long and fruitful life? When something is usually so bullet proof like the Classic is, it's strange when something suddenly goes wrong like this for seemingly no reason.

Edited by chimpsinties
Corrected a brain fart

Rocket Appartamento | Mahlkonig Vario | 58mm Rocket tamper | AeroPress | VST 18g basket | HappyDonkey Bottomless PortaFilter

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I've had the odd leak with silicon seals but found locking the portafilter a bit further so the gasket 'squishes' solved it.


Laissez les bons temps rouler

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It can only be the gasket, nicks in it or the mating surfaces? Check around the filter bowl first. Checking the group head is really hard upside down, even with a mirror, but look carefully where the gasket sits for any dings or blemishes around the groove. I don't think back flushing will help around the gasket seal. I use a brush to keep my grooves clean, but of course you can't do anything about the seal between the gasket and group head until you remove the gasket. I'm tempted to replace my E61 rubber seal with silicone but my reservation is silicone being softer may need less clamping pressure and distorts more easily? If yours is the genuine E61 portafilter and head I can't really see them wearing out unless coffee grains have caused wear grooves, but this can only be on the filter basket and they are replaceable.

 

My original E61 rubber gasket must have been in the group for years because it was so hard to remove. I think that's how rubber gives good life, it moulds and seals itself into the groove then hardens with heat cycles, whereas silicone should always stay soft. Personally I would like to try a ptfe gasket which is often used for high temperature steam sealing, but I don't think anybody makes them in E61 size. My suspicion would be that silicone is too soft and can wear or distort on the interface to the filter basket - compare the hardness specs of both materials.

 

If I am using the portafilter I only apply the minimum clamp pressure for a seal, but others in my house may use more brute force.

 

Presumably your water pressure is normal?

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I figured it was the gasket but having changed it twice, first for a silicone one and 2nd for a rubber oem one I really can't see why it would be.

I had another look under the shower screen holder and as you can see there was a bit of crud under there which I did my best to clean off. It might have made it a bit better but it still happens a bit.

Capture2.jpg

Capture.jpg

 

I've actually given up trying to fix it now. The machine has done me proud over the years and technically it still works. It doesn't owe me anything. I've put a shot through it at least every day since I got it and it wasn't even new then. I still use it every day but I've bought a 2nd hand Rocket Appartamento off someone on here, a machine I've been after for a long time anyway, so I pick that up this week. Excited much!


Rocket Appartamento | Mahlkonig Vario | 58mm Rocket tamper | AeroPress | VST 18g basket | HappyDonkey Bottomless PortaFilter

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Are there any hard bits of seal or coffee residue in the groove behind the seal ? This can cause the seal to leak.

Also check the rim of the basket, are there any slight dings / dents in it ?

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You'd think that wouldn't you but if you read my original post I've changed it twice while trying to diagnose this issue. First time for a silicone one and 2nd time for an OEM rubber one.

The machine will be going to the great 'spares or repairs' parts bin in the sky soon anyway so doesn't really matter. I was just curious to see if I'd missed anything obvious or if others has seen something I'd not already thought of.


Rocket Appartamento | Mahlkonig Vario | 58mm Rocket tamper | AeroPress | VST 18g basket | HappyDonkey Bottomless PortaFilter

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As the head looked quite shitty it did look s if it had not been cleaned thoroughly, I thought there could possibly be small hard bits of old seal will will cause a leak.

Have you removed the dispersion block and cleaned behind ? and around the perimeter ?

I did read your initial post and wondered why you would be using a ' blind' portafilter :confused:.

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Alright I see what I said. I was thinking about blind portafilters because the issue doesn't tend to happen if I used one and you'd think that would be as much pressure as you can get in the system. I have since seen it happen with a blind basket in so maybe it was just that I was tightening it more firmly when doing a backflush or something? Who knows.

I meant to say naked portalfilter.

Cheers for keeping me on point.


Rocket Appartamento | Mahlkonig Vario | 58mm Rocket tamper | AeroPress | VST 18g basket | HappyDonkey Bottomless PortaFilter

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Don’t suppose you resolved this one, did you? I’m having the same issue.


Gaggia Classic with OPV mod and Steam wand mod Mazzer mini French Press Aeropress

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Yep I sure did. It only cost me £800 too. I bought a 2nd hand Rocket Apartamento ;)

Sadly I never got to the bottom of the leak, the Gaggia is in the loft waiting to be donated to a friend of sold for parts. 


Rocket Appartamento | Mahlkonig Vario | 58mm Rocket tamper | AeroPress | VST 18g basket | HappyDonkey Bottomless PortaFilter

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