Olympia Cremina Rebuild Instructions Part 4
Sight Glass Seal R&R
- Indications: Water under machine, rust on expanded metal bottom
cover, point source corrosion or scale at sight glass.
- Tools Required: All of the aforementioned tools....wrenches
screwdrivers, everything but the snap ring pliers.
This repair is the most invasive of them all. It requires
complete disassembly of the machine, save the boiler and element. This is the
repair most people hope they don;t have to do and for good reason and the
general worry is that they will break the sight glass tube. This is usually not
a problem as we have never broken a tube if it was not cracked to begin with and
they always come out a lot easier than you think they would.
There are two different machine designs, differing in the
construction of the top channels which supply the steam valve on the left side
of the boiler and the sight glass and pressurestat on the right side. Earlier
machines have a full brass square tube which extends the entire width of the
machine. Our rebuild in this demo (1983) has only one half of this channel which
supplies the sight glass and the steam valve is supplied by a copper tube which
attaches directly to the boiler. There are slight differences in the rebuld
process as well.
The first goal is to remove the front stainless machine cover to
gain access to the sight glass from both the front and the back.
- Remove the machine cover panels after loosening the top boiler
- Remove the entire steam valve faucet assembly by disconnecting
the steam valve supply line in the case of the newer model using the 17mm and 12
mm wrenches, then hold the faucet firmly in one hand and use the 17mm to loosen
the holding nut on the back plate. You may need the mallet to loosen this. Work
the steam faucet out of the hole.
- In the case of the earlier model, remove the rear steam valve
cap with the 17mm wrench and take off the copper crush washer. Work the faucet
through the front plate. There is a O ring between the stainless plate and the
- Remove the group by loosening the 4 cap bolts.
- Remove the screws from the bottom front corners of the face
plate. The small nuts on the back are a little hard to get to so you may need a
needle nose pliers to hold them still while you unscrew the screws from the
- Lift the face plate away and set aside.
- Using the 17mm wrench, loosen the brass pressure relief valve
from above the sight glass assembly. Note the copper crush washer which may stay
on the channel or on the collar of the valve.
- Loosen the nut on the pressure stat tube and remove the pstat
by laying down beside the machine...unhook the wiires if you wish but it is not
- Loosen the brass sight glass retaining nuts fully.
- At this point you grasp the sight glass tube and twist it a bit
to break it free from the old seals while pushing upwards to slowly push the
tube through the seals. Keep the tube straight in relation to the housing. Be
aware that you can break it if you move it too far back and forth. The challenge
here is to get the tube moving and once it moves a little it becomes obvious
that it WILL move and so it is just a matter of carefully working it out the
- Once the tube is out and safely put away (note of
caution....soaking the glass in citric acid may soften the paint on the outside)
remove the old seals upper and lower.
- Assembly follows the reverse by first installing the new seals
in the housing sockets.
- Insert the glass through the top of the housing and slowly push
through the seals (you may want to use a bit of lube here to make this easier,
making sure the brass nuts are placed on the tube. You may want to start one
thread on the nuts to make it easier to keep track of insertion without worrying
about putting the nuts on at the last minute.
- Push and twist the tube all the way down into the lower seal.
The top of the tube should be flush with the upper seal. Make sure the line on
the glass tube is in the right orientation.
- Tighten the brass nuts until you feel resistance and then about
a quarter to a half turn more. There is no need to hammer these nuts down as the
fresh seal will expand under the nut to seal without that much tightening of the
- Install the pstat.
- Install the pressure relief valve using a new copper crush
washer. THIS is the one that you really hammer down.....tighten as tight as you
can by hand and then use the mallet to get it as tight as possible.
- Install the front face plate using a small screwdriver and tool
to hold the nuts in place.
- Install the group and tighten as in group R&R.
- Install the steam faucet, remembering to place the O ring
between the stainless face plate and the frame if you have the older type. With
the newer type simply install the faucet holding nut behind the steel frame and
reattatch the steam supply tube. On the older machine install a new copper crush
washer and then tighten the cap on the faucet thread and torque tighten as with
the pressure valve.
- Once you have everything back together perform a leak test by
heating the machine and observing for any hissing or water. The top crush washer
sealed fittings can be easily accessed to tighten a bit more using the mallet.
If you do have a leak at the sight glass it will likely not take much tightening
of the brass nuts to seal it so worm a wrench in there and tighten until the
leak stops and no more. Usually if there is a leak it will be one or the other
of the crush washer sealed parts.
- When you have assured yourself that all is well, install the
machine panels and finish by tightening the top boiler nut finger tight plus a
NOW THAT WAS A JOB!!!!
There are various and sundry small tasks to perform now and again, changing
feet, lubricating the cylinder or the piston pins, or other maintenance tasks,
but the above 4 jobs pretty much cover the possible rebuild or repair projects.
We did not cover unexpected facets of these opereations such as replacing
electrical connectors if needed or other complications which may arise. and
thankfully we have not had to source and replace any electrical parts, but in
general, all of the repairs are approachable and with some time and patience can
be done successfully. If you don't have the right tool, take the time to get it
before setting out on the job and it will go a lot better, likely since you will
have more confidence, especially if it is you first time doing possible harm to
your nice Olympia Cremina.
Please use this, in the spirit that it is intended, as a guide
for your endeavours - Doug's teacher at tech school always said "There are at
least a thousand ways to approach any task", and that is certainly true about
rebuilding your espresso machine!
We hope this helps and by all means take your time and ENJOY THE
Barb and Doug