Olympia Cremina Rebuild Instructions Part 2
Olympia Cremina Group and Piston R&R
- Indications: Water dripping from group with lever down. Water seeping from top of group when lever down, or up. Lever handle very difficult to move. Handle very easy to move. Coffee appearing in boiler. No espresso!
- Tools Required: 5mm hex wrench, 17mm wrench and crescent, wood mallet, snap ring pliers, seal chaser.
This job can be done with the group attached to the machine, but is much simpler and more thorough if you remove the group completely and work with the group on a towel.
- Remove the 4 group to boiler cap bolts using the 5mm hex wrench. If the bolts are extremely tight try a tap with the wood mallet. Do not force. If the original stainless bolts they should not be rusted and will come out but if they were changed to plain steel beware of snapping a bolt.
- Lay the group on work surface and loosen then remove the piston top cap nut and the retaining nut.
- Remove the seeger clips on the piston to lever pins using the snap ring pliers. Only open the ring enough to lift it off the pin. These rings often break when spread too far, or deform, so be prepared with some new ones.
- Push the pins through the handle yoke. If stuck, use a wood stick and mallet to drive them out.
- Remove handle and roller.
- While holding the group upright in the palm of one hand, strike the piston rod from the top with the mallet until the dispersion screen pops off into your hand.
- Finish knocking the piston out of the cylinder far enough to grasp with your fingers and pull out.
- Remove the rod seal C clip inside the cylinder with snap ring pliers.
- Remove the spacing washer and the old rod seal.
- Remove the group to boiler seal.
- Check the portafilter gasket which is still in place in the group. If it is pliable and you can get it out with a seal tool hook or small screwdriver it likely does not need to be replaced, but can be simply turned over to get some more use out of it. If the gasket is hard and brittle and will not come out in one piece, obviously it's time for a new one. Remove this gasket either way so you can clean the group and all areas of the cylinder.
- The simplest way to remove the old piston seals is to cut them off with a blade. Examine the inner walls of the cylinder. If there is pitting corrosion or scoring scour with fine emory paper (wet) leaving your hone lines parallel to the plane of the dispersion screen (around the cylinder not up and down).. Soak the entire group in descaler and cleaner as this is the big opportunity to really feel good about the cleanliness of the group before assembly.
- Install the new seals on the piston by rolling them over the piston face and settling them into the piston races with the seal tool.
- Install the new rod cup seal, ring and c clip.
- Place the piston insertion tool (the black cap provided with our seal set) on the tip of the piston rod, covering the threads and joining the shoulder of the rod.
- Liberally lubricate the insertion cap and end of rod with DOW 111.
- Lubricate the cylinder walls and the piston seals with DOW 111. Just a thin film will do since too much will just trowel along the cylinder wall and leave a built up glob.
- Insert the piston into the cylinder until the tip makes contact with the rod seal. Attempt to align the piston pin hole at a point where it will be in the proper position in relation to the top of the group.
- Push the piston into the seal while applying a rocking or wiggling motion, kindof a small circular motion while applying force until the piston rod pops through the seal.
- Continue the insertion until the first piston seal makes contact with the rim of the cylinder.
- While holding the group in one hand and applying constant pressure with your thumb or ball of your palm (not a lot- just enough to keep the seal edge against the cylinder edge) slowly and carefully work the edge of the seal into the cylinder rim. You will be able to see which areas need a bit of a "shoehorning" to get the entire seal lip under the cylinder rim. As you are applying force with your hand when all is inside the cylinder, the piston and seal will POP into place and the second seal will impinge on the cylinder rim.
- Again, while squeezing, check for any points that need a seal chasing. This seal will generally just POP into place on its own.
- Now that the piston with new seals is installed replace the handle, roller bearing and pins. You may have to insert a tool into the piston pin hole to align it properly with the handle yoke holes so everything is parallel. Choose whatever grease you like for the pins. DOW 111 works.
- Install the seeger clips on the pins.
- Install the top rod nut followed by the cap nut and tighten the two nuts against each other (not against the rod) using a crescent and your 17mm wrench.
- Install the portafilter gasket.
- Pop the dispersion sceen into place by starting one edge over the cylinder rim and pushing with even force to the opposite side using your fingers.. If you have trouble use a flat cup to pop it on.
- Install a new group to boiler seal and install the group onto the boiler.
- Install the 4 group cap bolts and tighten in an X pattern so the group tightens evenly and squarely. Do no overtighten but tighten fully and equally. If you need to retighten later this is better than overtightening.
- Make a cup or two of espresso, you deserve it!
Continue to Olympia Cremina Rebuild Instruction Manual, Part 3 for Boiler Gasket R & R