Caravel Piston Seal Replacement
As an Arrarex Caravel Espresso Machine Owner you, no doubt, share the enthusiasm of this machine's design, particularly in the area of maintenance!
We have chosen to use a 2 part seal. The U-cup has the proper ID, OD, and the correct overload, and the spacer keeps it tight in the race!
The piston is removable from the top, by simply turning the lock ring and pulling the entire piston out. The cylinder can be easily cleaned with a cloth once the piston is out. To replace the small O-ring inside the piston, one removes the C-clip inside with a Snap Ring Plier, lift out the piston shaft, and the old O-ring is easily removable, place the new o-ring in the groove at the center bottom of the piston, and reassemble.
The spacers & U-cups are assembled on the piston as shown. It is easiest to first place both spacer o-rings in the piston seal races. One spacer O-ring should be pushed all the way to the top edge of the top race, and the second O-ring pushed to the bottom edge of the bottom race. Then, install the U-cup seals (the new ones are quite stretchy) with the flat part of each U-cup facing each other. You will find that the U-cups will be quite secure, and will not move around in the race. Put a light coating of Dow 111 on the seals, rub some on the inside of the cylinder, and replace the piston in the machine. Very simple procedure - it only takes a few minutes & is well worth the trouble!
When the piston/cylinder of a Caravel espresso machine is leaking the first suspect is the small O-ring in the center of the piston. This seal can get debris lodged in it and a simple cleaning with coffee cleaner may be enough to restore function. If you cannot clean out the small ring and need to replace it proceed as follows.
- Remove piston assembly from cylinder
- Using a snap ring pliers, remove the clip inside of the piston body...this is not difficult, just small and awkward to deal with. Once the C clip is removed, pull the piston rod out of the piston body and remove the small O-ring. You may have a different clip holding the rod to the piston body...a kind of wire clip with a tab end, if this is the case, grasp the tab end with a needle nose pliers and compress the clip to remove. Again, not difficult, just awkward
- Clean the inside of the piston body and install new O-ring, the reverse of removal, making sure the retaining clip is seated in the inner groove.
To install new piston seals simply remove the old ones and clean the grooves. Roll the u cups into the grooves in the proper orientation )bottom cup faces down and top cup faces up). Install the spacer rings on the cup side of the seal. Lubricate the seals and insde of the cylinder and the job is done.
Please note, the piston seals may not need to be replaced, just the small O-ring, and it is easy enough to test this by installing the piston back into the machine for a check before changing the piston seals.
Click on each photo to see a larger view!
