Replacing the Group Gasket
Video of the resultsof a faulty group gasket
The group gasket is what creates the seal between the portafilter and the grouphead. It's also all that stands between you and 15bar of boiling hot water, so it's an important piece of the machine!
Every time you brew a shot of espresso, the portafilter gets clamped hard against the group gasket. The harder you lock the portafilter in, the more the gasket gets squashed, and the better the seal you get. Naturally though, with this regular squashing, the gasket will eventually begin to collapse, reducing the effectiveness of the seal. This is compounded when the machine is left on for long periods of time, as the heat in the grouphead assists in the degradation of the seal. One day when you load a very full shot, the machine will load up, you'll hear the pump go quiet, and then all of a sudden it will let go - the pump will take off as though there's no portafilter in sight, and about a second later you'll see lots of water (and wasted espresso) leaking from all around the grouphead. If these are your symptoms, then it's time to change the group gasket. Read on!
Disclaimer: Perform this at your own risk. The operation listed below has been performed with no complications other than those described, and has yielded satisfactory results, however basic mechanical skills are required to do this. It should be simply a matter of following the instructions, but since manufacturers can change their specifications over time and since I can make no guarantee as to the skills of the person performing it, I can take no responsibility if your machine is damaged during the operation.
Preparation:
- Make sure the machine is cold and is in an accessible location
- Remove the drip tray and waste coffee tray
- You may like to remove the water tank and bean hopper lid and turn the whole machine upside down, but this may not be necessary. If you do, ensure you don't push too hard at the grinder end as the hopper is not designed to take a lot of force.
The Short Method
Tools required:
- Small hook or right-angle tool (right-angle recommended if you have one)
Take your right-angle or hook tool and manoevure it between the group gasket and the portafilter locking shroud. Slide the end of the tool underneath the group gasket.
Take your right-angle or hook tool and manoevure it between the group gasket and the portafilter locking shroud. Slide the end of the tool underneath the group gasket.
Twist the tool so the right-angle or hook part turns underneath the gasket and gently lift it up. Repeating this procedure should allow you to completely remove the gasket.There will most likely be a lot of dirty coffee on the outside of the grouphead (see long method photos) which should be removed, and you may be able to use a small toothbrush and some water to remove as much as possible, however you won't be able to remove it all with the short method.
Lie the new gasket in position.
Using the back of the tool, gently push on the gasket so it slips below the rim of the grouphead. Ensure you do not use anything sharp for this procedure as you may damage the gasket.
After going all the way around, make sure the gasket is sitting perfectly flat and isn't caught on anything. You're done!
The Long Method
Tools required:- Stubby #2 Philips or medium flat screwdriver (only if you want to clean the showerscreen while you're at it - recommended, but not necessary for this operation)
- Small 8mm socket, extension and suitable ratchet
Look up at the underside of the grouphead, and you'll see a small hex nut in each corner of the rectangular portafilter shroud. Between the group and the shroud, you'll see an orange or black ring, which is the gasket we're trying to replace! In this photo, the showerscreen is already removed, but it won't be in your case.
Remove each of the 8mm nuts with the socket (the nuts undo anti-clockwise as normal). You may find it hard to get the socket all the way on to the nut, as the side of the portafilter shroud gets in the way - all I can suggest if it does is to push as hard as you can, or to find a smaller diameter 8mm socket. I ended up filing away a small section of thickness in the grouphead support to make it easier for next time. But even with that, as you can see it's still a tight fit! You will need to use the short method if you can't get the nuts off.
Having removed the nuts, pull and wriggle the portafilter shroud off the studs. Your gasket will be sitting there exposed, so just slide it off the brass grouphead. Half way there! If you want to clean the showerscreen, take the appropriate screwdriver, push as hard as you can safely, and VERY SLOWLY unscrew the showerscreen screw. You may find it too hard to remove.
The old and new gaskets - hmm, which is which?
The old and new gaskets with equivalent tension!
The new gasket is bright and springy compared to the limp, overheated predecessor.
Stray coffee grounds - evidence of a group gasket blowout
Having given everything a good wash and gotten it all clean, slide the new gasket onto the grouphead and refit the group support. Note: the portafilter shroud will go on either way, so make sure the opening for the portafilter at the front of the machine is to the RIGHT side of the centre point, otherwise you won't be able to get the portafilter on (learnt from bitter experience!)
Screw the 8mm nuts firmly back onto the group studs and you're done! This photo was taken after a showerscreen clean too - much better!
