Bezzera Family from the ground up - Page 2

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#11: Post by baldheadracing »

To, um, speculate - the shafts in other machines are screwed in with glue (like loctite), so heat may help. However, there's no easy way to grip so removal may be destructive.

... and no harm in testing the pressurestat before tossing it.
-"Good quality brings happiness as you use it" - Nobuho Miya, Kamasada

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#12: Post by Jeff »

fsarra wrote:Do you have a picture that shows what you mean? I've used an SSR paired up with a PID and thermocouple for temp control before but I'm not sure how the pstat fits into the equation.
Crayon scratches, maybe?

I'd do it along the idea of:

Line to one side of the pressurestat
Other side of the pressurestat to hot control on an SSR that can accept a 120 VAC control.
Other side of SSR control to neutral

Line to one side of the "Klixon" safety thermostat
Other side of safety to hot on the SSR output
Other side of the SSR to hot on the element
Other side of the element to neutral

This way if the safety thermostat opens, there's no power to either the SSR or element.

fsarra (original poster)

#13: Post by fsarra (original poster) »

Thank Jeff, I think I am understanding this.
Do you think this would be necessary if I don't plan on leaving the machine on for extended periods of time? I will likely be using this for one or two shots daily at most.

fsarra (original poster)

#14: Post by fsarra (original poster) »

Ok so I have some updates on the project. Ive been working on this in between other jobs at work so its a bit of a slow road.

I dont know if I wrote this in the last post or not but I took all of the group components that are chromed and soaked them in a bath of Evaporust for a few hours to remove any rust blooming in the chrome. The chrome was less than nice on some of the parts, especially the lever cam and the rings that the bearings press into.

The evaporust worked really well and with a rinse of water and light scrub, most of the rust came off.

Here is a pic of the piston after it soaked in evaporust and you can see how badly the chrome has pitted. At this point I had tried to put a little bit of penetrating oil where the shaft joins the brass head to see if I could unscrew the shaft but it didn't budge. Likely a combo of Loctite, corrosion from dissimilar metals, and rust.

From here I disassembled the rest of the machine and prepared it for a soak in descaling solution.
Some of this has been decumented by other posts but I thought I would add some more images of the valve assemblies and sub assemblies for anyone that needs them. When looking at some of the other machines out there on HB, it seems like there are a few variations of where the fill valve is located. Mine happens to be on the front right hand side.

This is how the valve and fill spout were assembled. The back side of the valve is connected to the boiler by copper tubing and the valve is a toggle style.

This is the safety valve assembly.

And this is the steam/water/fill valve assembly. My machine has knob style valves for the steam and water tap and a toggle valve for the fill valve. The only diffecence between the two types is the part that holds the knob or toggle. The rest of the valve is identical and as mentioned by other posts on the subject, the seals are readily available.

After a good soak in urnex dezcal, here are the parts laid out. They brightened up really nicely! I plan on polishing/cleaning some of the copper blooming off of the brass parts with an ultrasonic cleaner we have at the school I work at.

Here is the pstat post cleanup. It actually seems like it might work! The microswitch is also still available and is an easy swap.
Here is a link to the MF-02 microswitch. ... n-plunger/

And last thing for today is a simple trick for getting the steam wand out of the frame. I found the simplest and least damaging method was to gently bend the tube forward at a bit of an angle and this provided enough clearance to remove the wand.

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#15: Post by grog »

I wouldn't worry about the pitting on the piston shaft (where it's the worst right above the piston head). It will never be side loaded so there's no concern that it could snap off. There is still considerable material there so it's effectively just cosmetic.
LMWDP #514

fsarra (original poster)

#16: Post by fsarra (original poster) »

Agreed, it is not necessary. But for me I am seeking a cosmetic restoration as well so I will probably look to remaking the part from stainless. In the effort to give this machine a breath of new life, I think it's worth replacing if it will prevent more corrosion down the road.

fsarra (original poster)

#17: Post by fsarra (original poster) »

Ok, here is an update. A lot has happened since my last post but I haven't had the time to sit down and organize thoughts into sentences.

I wanted to post a list of links for various seals that I ended up ordering for this machine. I hope it is ok to post links?
I figured I will share various sources as well so that you can group items together from different distributors. If you have links to add to this or corrections/errors please feel free to share them and I can edit the list.

Piston seals ... ver-piston ... ton-gasket (these are the cafelat seals and I can confirm they do work and are much cheaper than the old style elektra seals below) ... -old-style

Group/shower screen seal ... millennium (I have not tested this seal under pressure yet but it appears to fit nicely)

110v Element (Can fit similar elements with 1" bsp thread) ... -mondiale/ ... duct/11834 ... duct/11827

Element gasket ... duct/15572 ... ry-gasket/

Pressurestat (any 1/4" bsp pstat will work here) ... -5-1-2bar/ ... a-marzocco

Anti-vac valve and T-fitting ... duct/16537 ... duct/17783 ... less-steel

Seal for anti-vac valve and safety valve ... oduct/9673

Boiler knob seal ... m?tracker= ... oduct/9108

External steam valve seal ... duct/13288

Internal seals for steam/water/refill valves
Cylindrical ... ra/5496042
Conical ... ra/5494004

Steam tip ... B00K49GMMW (have not tested myself just going off others suggestions)

Compatible water aerator??

Sight glass seals ... cchio.html (double check measurements) ... or-luluii/

Bearings for lever (these are stainless and shielded)

41mm Pressure gauge(that is what my gauge measured) ... duct/12166 ... -gauge-nsf (what I ordered, fits great and has a nice bezel) ... gauge-41mm

Bottomless portafilter ... ng_details ... y-shipping

Shower screen any recs for exact matches?
I found that a pre-mil La Pavoni Europiccola has a very similar shower screen. It is just a few mm taller. The bezzera measures in at 11.5mm and the LP at 14mm. I will be experimenting with using an IMS shower screen to see if that added space between the piston and inside of the shower screen is going to be an issue. If you have any other options please let me know and I will add them here.

Replacement Spring anyone have any ideas?
I will post dimensions as I have been messaged recently asking for them. I assume it will be a die spring of some sort.

fsarra (original poster)

#18: Post by fsarra (original poster) »

So I've hit a minor hiccup but not anything that was out of the picture.

In my attempt to remove the shaft from the piston (mostly for thoroughness, partly for posterity) I ended up shearing the shaft off :shock:

This was the shaft after all cleaning was completed and I just couldn't live with the pitting on there. It was already in my head that I would be remaking it.

oops :x

At this point my goal was to salvage the piston head so I threw it on the lathe and faced off the uneven sheared surface and bored out the steel hoping that I could get to the point where I could chase the threads with a tap.

These are the results off the lathe. I didn't have the right tap so I ordered an M12x1.25 from mcmaster carr and chased the threads clean.
Now it's all good and ready for a new shaft.

I got all of my new seals in as well as the new bearings an indicator light and pressure gauge. After running the metal parts through an ultrasonic cleaner and sandblasting the frame I went ahead and reassembled the machine for a pressure test. Since I didnt have all of the group components ready I just installed the cafelat gaskets on the piston, lubed it with dow111 and installed it into the group head.

This is the piston in the group.

The Semi-assembled machine

New wiring with high temp wire. I did order a brass cord grip that I have not installed yet.

And it's alive! Other than a few minor leaky fittings it ran really smoothly! The leaks were fixed with a little extra wrenching or ptfe tape.
The pstat worked albeit I had to adjust it since I had it taken apart and lost its previous setting.

The element was drawing around 12-12.5A while it was on which seemed normal?

The only weird thing was how discolored the water was after I emptied the boiler. I am assuming I just need to run water through it a few times to clear this out.

Hopefully its not something caused by my cleaning?

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#19: Post by beer&mathematics »

Great work! Can't wait to see it running!
LMWDP #431

fsarra (original poster)

#20: Post by fsarra (original poster) replying to beer&mathematics »

Thanks! :D yours was one of many informative posts that has helped me along the way!