La Marzocco GS/3 Rebuild Starting Soon

Equipment doesn't work? Troubleshooting? If you're handy, members can help.
Mike48123
Posts: 5
Joined: 3 months ago

#1: Post by Mike48123 »

I bought my GS/3 new about 15 years ago and it's seen quite the use. My SN is 507, my gut says it was a fire sale machine but I thought I read something a long time ago that said the sn wasn't part of it. Either way, I've done a lot of work to it over the years; replacing the drain valve on the steam boiler, replacing the OPV, replacing different check valves and solenoids, outboarded the pump, and I think that's about it.

About a year or two ago, I've noticed that as it heats up, the thermal fuse blows and gets really hot. I *think* this may be related to the heating element. I ran an ohm check two-ish years ago and it was borderline replacement. I've also noticed black flecks in the water for awhile. I'm hoping that it may be flecks off the heating element and not mold. As a result, the machine has been sitting, off and unused, for a few months now until I can figure it out.

I have to take a few weeks off work soon and figured this may be the time to rebuild the machine. I'm not sure exactly what I'll need, but going through a few threads from Jake_G, I think this should be a good start. My plan is to take everything apart, group head and all, and clean it all up.

Qty | Name | SKU
10 | 1/8" copper washer | 3500-02
10 | 1/4" copper washer | 3500-04
10 | 3/8" copper washer | 3500-06
2 | 75 Durometer Viton O Ring | PKG-HF-222v75

1 | Food grade silicone lube for o-rings
1 | RectorSeal 5

I have a feeling that I'll replace the gicleur as a preventative measure, but not sure which one to get just yet. I'll probably call LM for that, the gaskets for the group head, and then two heating elements. Other than that, is there anything else that I'm missing that I should be getting?

My goal is to also try to film this as much as I can so that it'll help others too. Maybe it will be great, maybe it will be a disaster. Who knows...

User avatar
bostonbuzz
Posts: 1248
Joined: 13 years ago

#2: Post by bostonbuzz »

Not sure how deep you're going on the rebuild. I just did a 100% complete rebuild on a machine that was pretty nasty and I didn't trust any part of it (powder coating frame, full disassembly, acid bath all parts, all rubber replaced, etc.) La Marzocco GS3 AV --> EP Paddle Mod

The check valves got me. They were pretty gross with scale and I replaced the orings like Jake did. I broke a snap ring or two as well. On reassembly two of them sheared apart and cost me a week. The new stainless ones are really nice but $75 each. It's a good idea to pick up a couple of those.

Also, one of my solenoids stopped sealing (steam boiler overfilling when brewing coffee) so I got a new plunger ($30), which is also good to have spares on hand.

Your motor mounts might be shot. You can see if you take the side cover off.

I took the entire machine apart and cleaned everything before I ordered parts since I had my old machine working.

I remember those crush washers took forever to ship.

I got all my orings from "orings and more". LM has the sizes in the parts diagram.

I have a whole spreadsheet if you're interested.

You'll need heating element gaskets. Those elements are $$$ so you may want to order both so you have them on hand and return the one you don't need. The 120v stuff from LM is 3x the price of the 220v stuff for some reason.

Edit: There are some upgrades like the gliceur tube, a couple extra check valves for safety (I think 7 is the latest total) and maybe others I can't think of you may want to consider.
LMWDP #353

Mike48123 (original poster)
Posts: 5
Joined: 3 months ago

#3: Post by Mike48123 (original poster) »

bostonbuzz wrote:Not sure how deep you're going on the rebuild. I just did a 100% complete rebuild on a machine that was pretty nasty and I didn't trust any part of it (powder coating frame, full disassembly, acid bath all parts, all rubber replaced, etc.) La Marzocco GS3 AV --> EP Paddle Mod
I'm planning on going pretty deep. I've never fully taken it apart, and it's always been questionable about if it was part of the fire sale or not. I feel like it's always worked well, but just borderline well.

I probably won't do powder coating, but I'll have to read about the acid bath.
bostonbuzz wrote: The check valves got me. They were pretty gross with scale and I replaced the orings like Jake did. I broke a snap ring or two as well. On reassembly two of them sheared apart and cost me a week. The new stainless ones are really nice but $75 each. It's a good idea to pick up a couple of those.
I ended up replacing maybe all the check valves a couple of years ago. I had an issue with them and LM recommended replacing a couple of them. I have to see if they are stainless or not. I think they are, because LM was like "these are new versions, why not upgrade".
bostonbuzz wrote: Also, one of my solenoids stopped sealing (steam boiler overfilling when brewing coffee) so I got a new plunger ($30), which is also good to have spares on hand.
Good call. I've replaced the solenoids but I don't think the plungers. I honestly can't remember... I do remember the solenoids.
bostonbuzz wrote: Your motor mounts might be shot. You can see if you take the side cover off.
Another good call. I took the motor out because I was tired of my cups dancing around. :lol: But for others doing it, they may want to.
bostonbuzz wrote: I remember those crush washers took forever to ship.
Did you order them from LM or from that place Jake did? And these are those copper ones?
bostonbuzz wrote: I got all my orings from "orings and more". LM has the sizes in the parts diagram.
I was planning on doing something similar. I love LM, but I have to check the prices and availability.
bostonbuzz wrote: I have a whole spreadsheet if you're interested.

You'll need heating element gaskets. Those elements are $$$ so you may want to order both so you have them on hand and return the one you don't need. The 120v stuff from LM is 3x the price of the 220v stuff for some reason.
If you have the spreadsheet, please send it! I don't know what format it's in or if you can post it here. It would be extremely helpful and save so much time!! Thank You so much!!!!!

As for the elements, yes.... I should had ordered them a couple of years ago when the machine first started acting up. I think they were half the price back then.
bostonbuzz wrote: Edit: There are some upgrades like the gliceur tube, a couple extra check valves for safety (I think 7 is the latest total) and maybe others I can't think of you may want to consider.
I'd like to check out these upgrades since I'm doing all this work. I know I re-routed the steam boiler OPV with tubes into the drain box, and swapped out a few of the check valves. I'm not sure what else needs to be upgraded.

Thank you so much for all this!!!

EDIT: there was a some weird format issue that I had to fix.

User avatar
bostonbuzz
Posts: 1248
Joined: 13 years ago

#4: Post by bostonbuzz »

Not sure if this is intelligible or not. It wasn't made for public consumption so ymmv.

https://docs.google.com/spreadsheets/d ... xEiOY/edit
LMWDP #353

Mike48123 (original poster)
Posts: 5
Joined: 3 months ago

#5: Post by Mike48123 (original poster) replying to bostonbuzz »

Thank you very much. This is great. A lot of these vendors looked a bit sketchy but it makes me feel better knowing that you ordered from them.

I probably don't need as much as you did, but this is a fantastic start. Thank You!!