With pliers, loosen the spout under the 3 way valve starting from the right side and moving pliers to the left. Once loosened, remove them by hand.
With a 9/16″ open end wrench, loosen the nut below the black box starting from the right side and moving the wrench to the left. Once loosened, remove the nut by hand. Two small washers will come out – first the unlevel one and then the very flat one.
Slide the black box down shaft. This can be a little difficult to pull down due to the wires.
The shaft is part of the big nut attached to the brass. With a 7/8″ wrench on the nut below the brass, loosen the nut and shaft starting from the right side and moving the wrench to the left. The shaft is on VERY tight.
When the shaft is removed, there is a piston inside. If it does not spring out, use a small flathead screwdriver to try to pry it out from the outside perimeter outside of the red ruby.
If the piston was stuck, you will need to clean the inside of the shaft and make sure there are no rough surfaces. Lubricate with a little or every small film of olive oil on the inner wall of the shaft. Place the piston back in and test by pushing it in with your finger about 10-15 times and allowing to pop out. Everytime it pops out, rotate the piston 1/8th turn to make sure the piston pops out from all positions.
The previous picture has the piston in the up position. This gets re-assembled back into the brass. The picture to the right shows the inside wall of the shaft with the piston removed.