Please remember - this is a guide of our experience only and you may have a better, or more efficient technique, or find a way to improve upon our method - use the information at your own risk!
We are demonstrating the rebuild using the older model machine - the newer model proceeds identically.
The group of the Faema Faemina is composed of a removable cylinder, and a TWO part piston body. Seal is achieved by a solid rubber seal on the piston, and there is a thick rubber sealing washer (Gommino on Faema diagram) between the two piston halves which opens when the piston rises, to allow water into the cylinder through the holes in the lower half of the piston, and closes when the piston descends under spring pressure. The sealing washer is as critical to sealing the piston as the piston ring seal is. When assembled the two halves of the piston are not rigid - they are not tightly connected to each other, and there remains a small space between them.
It is quite an ingenious design - pre-infusion and filling the cylinder is completely independent of the movement of the piston seal within the cylinder (the piston seal does not pass any water inlet - this is different from the way most of the home lever machines work.) Most noteworthy in the design is that the pre-infusion stage takes place when the lever is pulled down only VERY slightly - it takes VERY little effort for the Gommino to be moved enough to allow the water to enter the cylinder. The implication is that, unlike many spring piston machines, that require the operator to 'hold' the lever all the way down against spring pressure for pre-infusion, with the Faemina one only very slightly pulls the lever - when you see the first espresso drips you push the lever all the way down, and release it. When you release it, the Gommino seals, the piston seal takes over on the downward stroke, and Voila!
The rod is sealed by a loaded U-cup which is held in place with a collar nut.
The removal of the piston proceeds generally in the following manner:
If the machine needs to be descaled do it before disassembly. Once you begin the rebuild you'll have a lot of open holes in the machine, so if your Faemina holds water, descale first.
The tools need for both disassembly & assembly are:
Needlenose pliers or spanner wrench
A small hook tool
Hammer or mallet
A blunt awl or thin drift
Did we mention Patience?
Remove the bottom base cover, and drip tray to better access the bottom of the group. With lever still in place remove the dispersion screen, remove the portafilter gasket and the paper shim under the portafilter gasket. You may leave the lever, but leave the piston retaining pin in place.
Remove the sight glass by turning the outer bezel CCW, and set aside.
Remove the cylinder by turning the entire cylinder counter clock-wise. Ideally this is done using a spanner socket - if you have no spanner socket, you can improvise with a hammer & blunt awl AFTER soaking the cylinder threads for a few days in penetrating oil. (the photo below is one of reassembly, and shows the cylinder being put back in CW)
Once the cylinder is completely unthreaded, pull it out & set it aside.
The next step involves compressing the spring, to remove the piston rod retaining pin, followed by releasing the tension on the spring, and removing the piston assembly. This is accomplished using the large clamp. A spacer is needed (we use a short piece of PVC Pipe) to place against the face of the piston. The clamp is applied & tightened, allowing the removal of the upper piston retaining pin.
After removing the pin, slowly loosen the clamp, releasing the tension of the spring. The piston may simply pull out, or fall out, or you may need to set the machine up on its base, and use a wooden or metal drift & knock the piston down out of the machine by tapping on the top of the rod. At this point your piston & spring are removed from the machine.
Next step, using a socket wrench, remove the collar nut which holds the piston rod seal in place. Remove the piston rod Loaded U-cup seal. At this point, you are ready to reassemble - now is the time to clean all the surfaces, polish the parts, clean the threads on the cylinder, and be proud of yourself that you've gotten this part of the job done!
What follows is the fun part - assembly! Keep in mind, you will be making some GREAT Espresso when this is done!
FAEMA FAEMINA ASSEMBLY INSTRUCTIONS:
The tools to put it back together are the same as those used to take it apart.
Once you have it all in pieces, clean everything to your satisfaction, polish the parts, have your tools & seals ready & at hand. About an hour and a half, or two of free time, and your patience...
First, assemble the piston. Replace the Gommino Washer between the two halves of the piston assembly. Install the spanner nut, and tighten metal to metal. Smooth the rod with fine steel wool if needed - there may be rough spots around the piston pin hole. If it feels rough use some sand paper to smooth it out - you want to make sure there is no metal spur to snag the seal. Assemble the collar nut, the load O-ring and the U-cup on the rod - use liberal amounts of Dow 111.
Don't forget the spring!
Insert the assembled piston, with spring, into the group housing making sure to align the piston pin hole in the rod in the proper orientation in relation to the top housing.
If resistance is met when inserting the rod in the housing you may need to tap with a mallet.
Using the PVC Pipe spacer, place the clamp on the group - the same as during disassembly. Be careful not to block the movement of the rod at the top of the housing.
The clamp needs to be tightened to force the piston rod up through the housing, but not all the way - the spring must be left loose (check through the sight glass hole). Slide the seal retaining collar nut into the socket. This is the most difficult part of the rebuild - the seal collar nut has 2 holes in the top which are used to tighten it in place. You may need to rotate the spring to allow access to the holes. The nut is turned CW, using a hook tool.
Under NO circumstances should you attempt to install the seal & nut before the rod - this WILL DESTROY THE SEAL - it MUST be done in place after the rod has been inserted through the seal. The tighening of the nut may be eased by appying mineral oil to the threads. Once the nut is started, pull or push with the hook tool CW until you feel resistance - about 3/4 turn. You may need to rotate the spring to allow access to the holes (this is why the spring must be loose.) Have a flashlight on hand so you can see the holes. The holes are drilled in the nut for ONE reason only - to allow the nut to be tightened with the seals in place. It doesn't have to go far, just tight enough to be difficult to turn it any more. This is the most difficult part of the assembly, and requires some fiddling, perhaps a custom tool made on your part. It's a pain, but NOT impossible.
It may be helpful to practice tightening the collar nut through the sight glass hole without the seals or the spring so you can get the hang of how it's done - then proceed!
After the collar nut has been tightened squeeze the clamp a bit tighter until the piston rod pin hole is fully visible. You may need to align the rod pin hole with an awl or screwdriver to allow for the pin to be inserted properly.
Leave the clamp in place to allow easy alignment of the rod pin hole. Once aligned install the pin & rollers and C-clips.
Remove the clamp. Install the lever.
Install the cylinder (make sure the square seal is in place), by liberally lubricating the threads with mineral oil, inserting it, and turn CW by hand until tight, then by using your awl & mallet in the holes. You may have to hold it on your lap to be sure it is tightened completely. Tighten until there is about a 1mm difference between the piston face and the cylinder edge. You will feel resistance against the seal.
Install the Sight Glass Gasket, glass and Bezel. Finger tighten the bezel - no tools are needed.
Snap the dispersion screen in place, and install the portafilter gasket.
At this point your Faemina is rebuilt! Fill it with water, and check for leaks. The most common leaks that you may experience are through the sight glass (tighten the bezel further), or the cylinder - empty the water, and tighten the cylinder a bit more.
You will be very pleased at the results of your efforts! We hope your ENJOY THE ESPRESSO FROM YOUR REBUILT FAEMA FAEMINA ESPRESSO MACHINE!
If you have any questions - don't hesitate to email us - we love this stuff as much as you do!
Rebuilders Note: If your machine is leaking from the bottom of the group, and your rod seal is NOT leaking at the top, you may choose to perform a Short Block Rebuild of only the lower part of the group. The design of the machine allows one to remove the piston body & cylinder while the spring, and lever remain in place in the machine. This is accomplished by removing the spanner nut at the end of the piston face, and unscrewing the cylinder. This gives access to the thick inner piston sealing washer, the cylinder to body seal, and the piston seal itself.
From a practical standpoint, the removal of the cylinder is the most arduous part of the rebuild, so a complete rebuild, including the piston rod seal ("while I'm in there...") makes a bit of sense! At the same time, if you're conservative with your parts, or firmly believe in the 'If it's not broken, don't fix it' theory, this partial rebuild may make sense for you!