This will show you how to remove the brew group gasket and install a replacement. Note: We strongly advise draining as much water as possible from the boiler before you start. Empty the reservoir and put the machine next to the sink. Turn the machine on, point the steam arm into the sink, open the steam knob and press the brew switch. When the water slows down out the arm, tilt the machine toward the sink until the drops stop coming out. Power the machine off. For further detail, refer to the Gaggia parts diagram for the part numbers listed below. Step-by-Step Instructions Please read this entire document before you start. Unplug the machine and make sure that it is completely cool before beginning Remove the water reservoir, portafilter, and drip tray. Remove the steam knob (#22) on top of the machine by pulling straight up (you may need to pry it up by using a flat blade screwdriver. Look for the two small indents between the button cover (#21) (toward the front of the top) and the flat top of the machine (#23). Using a small flat blade screwdriver, pop up and remove the button cover (#21). Remove the two Phillips screws (#42) down under the button cover and the one (#42) down in the center of the water reservoir area. Remove the four 4mm Allen bolts (#35 – pg. 2) from around the group head area underneath – they are located around the area that you would lock the portafilter. You should now be able to lift out the entire boiler assembly (#12, 20, and 24 – pg. 2). Remove the four 5mm Allen bolts (#2 – pg. 2) around the corners of the boiler assembly. Note: The boiler may still contain some water, so have a small towel handy to soak it up. Remove the boiler (#12 & 20) from the retaining ring (#24 – pg. 2) and locate the black gasket (#38 – pg. 2) on the bottom of the lower boiler piece. Remove the gasket and clean off the surfaces in that general area. A stiff brush and some descaler (like Urnex Cleancaf or Durgol Swiss Espresso Descaler) can help to remove tough buildup. Put the new gasket in place. Make sure that it is properly seated. Reassemble the machine. Replace the drip tray and water reservoir. Fill the reservoir and plug the machine in. You should now be able to brew without any leaks.