Saturday, November 21, 2020

Off-topic: Fixing a leaking steam wand on a Saeco Aroma

 Yes, this still is a bike blog. But we all know there is some overlap between the bike and the coffee scene. So please allow me to publish a very brief post on fixing my espresso machine. 

I have a Saeco Aroma, bought refurbished in 2013. It's just enough espresso machine for my needs, and it's been working reliably for years. There always had been a little leakage from the steam wand into the drip tray, but only recently the dripping increased to a point where I needed to do something about it.


 

I spent a good amount googling around for a solution. Every espresso maker is a little different, and there are lots of different kinds of leaks and causes for them. Eventually I found a link to what sounded like a solution to my problem. However, the link produced this:

A 404 error :(


 

Internet Web Archive to the rescue!The page was indeed archived. What was missing, though,  were the pictures. Fortunately, espresso makers aren't particularly complex pieces of technology, and so I could figure things out based on the text alone. For the sake of posterity I thought I'd document the process.

  1. Unplug the machine. Make sure the machine had enough time to cool down. 
  2. Remove the water tank and loosen the two Philips head screws that hold the metal cover in place. Don't lose the serrated washers
  3. Remove metal top
  4. You can see how the steam knob has a snap ring and a washer on it. Those two parts prevent the knob from being turned all the way out. 
  5. Remove the snap ring. There's a good chance it'll fall somewhere into the machine, but it's easy to get it back out with a magnetized screwdriver. 
  6. Keep turning the steam knob counter-clockwise until it comes out. Put the large metal washer to the side.

 

The lid is off


Snap ring


 

Snap ring removed; washer and knob still in place

Knob removed. There appears to be some corrosion on the tip

After rubbing off the corrosion, you can see that there are two grooves in the tip of the knob. This is what is causing the leak. 

 

The original instructions said to use use 220 grit sandpaper and steel wool to remove the grooves. This is where things got a little tricky: Without a visual reference, I wasn't sure how much material to remove.So I took it slow, starting out with extra-fine steel wool. The grooves were still visible when I tested thing the first time, and indeed there was still dripping. I removed a little more material, now using sandpaper. Brass is soft, and so it doesn't take long to remove a lot of material -- be careful, and maybe use a finer grit sandpaper. The second time round it seems like I got it right. There are still a couple drops when pulling a shot, but way less than before.

Pretty smooth now!

 

Reassembly is easy, except that I couldn't remember which of the two grooves on the know the snap ring went on.

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