This thread / post will happen in multiple parts which I will add to when I have free time.

I purchased a used Quick Mill QM67 (generation 1) double boiler E61 espresso machine. The seller had bought it originally from a bagel shop but the seller never used it himself. The seller pulled a shot for me to confirm everything is working - so I left with a pretty good idea that the machine was functional.

FWIW, I've owned two other espresso machines previously, but this is my first E61 and double boiler machine.

Once home with the QM67 first thing is to take some before shots:




Next step was to check the state of the group by disassembling it.





Not terrible. Gaskets and pins are pretty worn which is to be expected for a machine that's probably seen a lot of use at a bagel shop.



Look inside the chamber - no obvious scale build up. Maybe I got lucky?

Next taking off the shower screen ...



Looks like it's never been cleaned in 13 years and I drank a shot from this at the seller's house!

Next update is where the fun begins - opening up the machine and looking inside.

Opening it up and removing the water tank and cladding reveals the internals in all its gory details.



At this point, I wasn't regretting my decision to buy the machine (yet), but I was definitely wondering what I should do first.

Two things stood out right away: the insulation on the boilers was missing, and the boilers looked to be in pretty rough shape. It looks like oxidization on the steam boiler (right), and some sort of residue on the brew boiler (left).

Lots of the components is covered in some sort of mildly sticky substance.

Closer look at the steam boiler...



Surface oxidization I can live with... hope that's all it is.

Closer look at the brew boiler... at this point I'm even sure what to think.



Below: Close-up of the steam boiler connections... some nice build-up of some sort of substance.



Some scorching on the connections at the top of the brew boiler. I'm getting a pretty good idea what happened to this machine.



It looks like during its operation, something was accidentally spilled onto the machine. The exterior machine, while looks fine, has residue that's been cooked onto the grouphead. The substance appears to have shorted out some connections and ruined the insulation on the boilers which have been mostly removed.

Since I saw the machine working at the seller's home, at least the electrical is functional. The wiring looks dirty but the insulation is intact. The boilers need some investigation but maybe everything just needs some cleaning?

Up next, tearing it down...

Those insulators discolor and decay even in benign, home use. They can be replaced with higher-temperature ones available though Mouser or similar electronics suppliers. They slip over the existing crimped FASTON-style connectors. I'll try to dig up the part numbers tonight if another doesn't beat me to it.

Welcome! Really nice machine and I'm looking forward to seeing all your updates.

Before starting the tear down, everything gets labelled and photographed before disconnecting.



Everything got removed so it can get cleaned up.





Copper tubing, connectors, and the grouphead all get mild citric acid baths to remove any oxidization and scale build up. Pipe cleaners and mild dish detergent were used to clean up into the copper tubing.



Filthy dispersion area gets a good cleaning... 13 years of dirt requires multiple rounds of Cafiza soaks and scrubs.



The boilers were a challenge. The heater element would not release easily from the boiler with a wrench. The steam boiler was already previously dented and I did not want to risk additional harm.




To clean the boilers I removed whatever tubing and attachments that can be easily removed. Some connections were seized onto the boiler. I left these in place as I didn't want to risk damage, and I did not want to use WD40 on something I'd be drinking from.

Using very mild citric acid solution, I filled each boiler as best as I could using a funnel and let each sit for 15 minutes before getting flushed with tap water. Lots of sediment and mineral build up came out both boilers, the steam boiler in particular had a lot of crusty bits. It's possible water was left in the machine during storage. I did two rounds of acid solution soak and multiple flushes until sediment cleared from both boilers.

From what I could see through the openings, the heater elements had a bit of white scale built up on it. Without being able to disassemble the boiler, a proper descale will have to wait.

Up next - reassembly, and dealing with leaks.

Questions
Is there a safe and easy way to remove the heater element from the boiler if it's seized on? The shape of the boiler makes it hard to secure or hold in place while trying to work on removing the heater.

How easy is it to find replacement brew and steam boilers?



In the bottom-right corner there appears to be a transformer. When removing it for cleaning, there was a white substance between it and the bare metal of the chassis. Is this thermal paste or is it something else? I assume it is thermal paste, but want to be sure.

Jeff wrote:Those insulators discolor and decay even in benign, home use. They can be replaced with higher-temperature ones available though Mouser or similar electronics suppliers. They slip over the existing crimped FASTON-style connectors. I'll try to dig up the part numbers tonight if another doesn't beat me to it.

I've never shopped at Mouser before. What a catalog! If you can find me a part number or product name that'd be awesome.

A deep, impact socket works reasonably well. Impact drivers have become more common now with recent generations of battery-driven tools.

The ones I last ordered were TE Connectivity 1969632-1 and 1969507-2. I don't remember why one was in white and the other in black. Edit: Likely driven by the black, straight, 1/4" ones being rated at 200°C

Here's a horrendously long link to the High Temperature FASTON Housings sell sheet

I assume it is thermal paste, but want to be sure.

Yes, that's thermal paste, and it is highly necessary for this machine. It gets pretty toasty during regular use.

The heater element would not release easily from the boiler with a wrench.

The newer QM67's like yours need to be fastened rather tightly, because they rely on compressing a thick teflon gasket to seal them. Older versions used an o-ring, which did not require as much force. It's tight enough that a regular wrench or socket wrench unfortunately will not do the job. An impact wrench is required to loosen and tighten the elements. I'd honestly recommend replacing the teflon gasket if you're going to go through the effort of removing it in the first place. You'll need either a 1 7/16" socket or a 37mm socket.

OMG I think I saw this machine on kijiji 2 weeks ago and almost bought it......
I am glad to see it showing up here and definitely going to follow through your rebuild!
I ended up getting an Isomac HX machine to rebuild instead.

Good luck with your rebuild and feel free to message me if you are looking to source parts!

Jeff wrote:Here's a horrendously long link to the High Temperature FASTON Housings sell sheet

Thank you! I'll order some the next I plan on poking around inside the machine.

GreenEggsAndSam wrote:Yes, that's thermal paste, and it is highly necessary for this machine. It gets pretty toasty during regular use.

Thanks for the confirmation. Right now it's using thermal tape which isn't ideal. I got to see if I have any spare thermal paste lying around in a box somewhere.

GreenEggsAndSam wrote:An impact wrench is required to loosen and tighten the elements. I'd honestly recommend replacing the teflon gasket if you're going to go through the effort of removing it in the first place. You'll need either a 1 7/16" socket or a 37mm socket.

Good to know. As much as I'd like to get everything into a like-new condition, this is one of the situations where I'm leaning more toward "if it ain't broke" approach. I'll consider replacing the teflon gaskets if I ever find the desire to fix up the boilers.

strikeraj wrote:OMG I think I saw this machine on kijiji 2 weeks ago and almost bought it......
I am glad to see it showing up here and definitely going to follow through your rebuild!
I ended up getting an Isomac HX machine to rebuild instead.

Haha! Yes, that's the one. Small world! Good luck with your rebuild too! I'll keep you in mind if I ever need to find parts.

Good to know. As much as I'd like to get everything into a like-new condition, this is one of the situations where I'm leaning more toward "if it ain't broke" approach. I'll consider replacing the teflon gaskets if I ever find the desire to fix up the boilers.

Unfortunately, it looks like it is going to need to be replaced. There's a lot of mineral buildup around the seam between the gasket and the boiler, so it might be leaking at the moment. After descaling, you might reveal the gaps that the scale is currently sealing.