HOW OFTEN SHOULD YOU REPLACE YOUR GROUP GASKET?
Espresso machine group maintenance services should be performed quarterly or at the very least twice a year for lower volume shops. We recommend changing the gasket as well as the screen and screw in your group. The longer you wait the harder the group gasket can become.
HOW TO CHANGE THE GROUP GASKET
Please note: If the group gasket has not been changed recently it will may hard and brittle and will likely come out in chunks/pieces and may need to be chiseled or picked out. It is important that you remove every bit. Remember eye protection during maintenance.
1. Remove the group screen with a screw. For machines without a screw, the screen is held in by the group gasket. When you remove the gasket, the screen will also be removed.
2. The group gasket fits inside a groove in the group head. It may be difficult to see the gasket, as heat will carbonize the rubber. Using a scratch awl or an “o-ring pick set”. Insert it up into the gasket at either 3 or 9 o’clock. Pull the handle toward you and raise the handle up to pry the gasket down from the groove.
3. Once you have removed all of the gasket, thoroughly clean the groove so it is free of old-gasket debris and coffee residue. The half-moon brush is a great option. If not completely clean, the new gasket will not seal properly. Also, use this opportunity to scrub the group diffuser clean if your machine has one. A solution of Espresso Parts espresso machine cleaner and water and a brush should make short work of any coffee build up.
4. Once the groove is completely clean, the new gasket may be installed. Lube is not required and should not be necessary. Most group gaskets have one side that is flat and one side that is beveled. The beveled side goes up and into the group. On machines that use the gasket to hold the group screen, make sure you replace the screen at the same time. Using a short stubby screwdriver, press the gasket into its slot in a circular motion. It may be helpful to remove the basket and press the portafilter into the group gasket. Then put the basket back in and press again to make sure it is sealed.
5. Check the fit of the gasket and position of the portafilter. The portafilter should sit at about the 6 o'clock position, not too far to the left or the right. If the portafilter is too far to the right, a shim should be used. If the portafilter is too far to the left, a thinner gasket should be used.
6. Now it’s time to pull a shot, season the machine, and test for leaks.