How to change a Breville BES870 Leaking Group Seal

Breville make a range of nice little semi automatic coffee machines, the BES870 is a good example. It has a built in conical burr grinder, making it easy to prepare a good quality coffee.
The unit in question came in to the workshop because it was leaking around the portafilter during coffee extraction. I also replaced all the hydraulic o-rings, those around the hot boilers were quite worn.

Breville coffee machine




I will briefly describe how you can change the group seal on your Breville Coffee Machine. Firstly make sure you order the correct seal. There are variation amongst the various models. These seals are not as robust as the commercial machine group seals. The picture below shows the crack in the old one that I removed from this machine, sitting next to the new one. The BES 800 Series Steam Seals can be purchased here

Breville Group Seal


In order to remove the group seal, it’s easiest if you lie the machine on its back. Do empty the water tank, bean hopper and waste first. You will need to then remove the central screw holding the shower screen and lever the shower screen out. This will come out without the group seal in most cases. You will need to give it a good clean. It will be dirty and clogged with coffee particles.

Greville coffee machine shower screen removal
Using a pick, lever out the old Group Seal. Then clean around the housing. Assemble the new group seal on the clean shower screen.


removing the group seal

Greville Coffee Machine Shower Screen


Install the new seal and clean shower screen. Using a blunt instrument, make sure it sits back in firmly. Use the Portafilter as a tool by connecting it a few times to make sure the seal is in and flush, Don’t forget to replace the screw.

Done your group seal and shower screen good as new.

Not quite yet. As the Breville machines age, the inner plastic collar that the portafilter screws into wears. meaning sometimes you can change the steam ring or group seal and the portafilter still feels loose and may leak. In this case we can use a packer placed behind the group seal. Browse the Breville coffee machine parts for a packer.


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