Faema Marte mercurio shaft gasket

Are you rebuilding your Faema Marte or first series Mercurio. Then it is always handy to replace the shaft gasket.
To replace this part you need to do the following things:

• Remove the piston from the piston rod;
• Remove the 2 screws on each side of the top of the group;
• pull the piston shaft true the top of the lever housing;
• now you can remove the bottom nut of the lever housing, behind this is the original u cup seal;
• replace the old one and do the processes the other way around.