Krups 968 Espresso Machine

AKA “fix my leaky Krups espresso machine”

Hey folks,

So, in my eternal quest to make all of the appliances of the world last forever, I picked up an old espresso machine at one of my favorite local stores, Urban Ore. Urban Ore is like a giant thrift store full of tools and house parts and general craziness. It feels completely dangerous, and only vaguely organized. It should have a sign at the door that says “No Shirt, No Shoes, You’re Stupid.” I’m pretty sure running through this place buck naked would net you a nasty case of tetanus and absolutely no attention whatsoever from the patrons or the employees. Prices are completely all over the place- They seemingly roll a couple 9-sided dice or maybe use a Magic 8-Ball to price things. I’ve seen two of the exact same item, sitting right next to eachother, with one priced $3 and the other priced $75. I bought an antique door for my house there once. Another time, I got a DVD player and a, um, “vintage” (beat to hell) toolbox to toss in the back of my van.

The place is a trip. If you find yourself anywhere near Berkeley, I highly recommend checking it out.

Anyway, so I got this old Krups “Type 968” espresso machine for $5.
Krups 968 Espresso Machine

I already knew it was going to have problems when I bought it, because, well, Urban Ore, but also because it had this note taped to the top by the previous owner:
Silly note about broken machine

Judging by the amount of coffee ground crud jammed in all the machine’s crevices, I’d say the author of this note is not quite connected with reality. It most definitely has been used, more than once.

So, I filled it up with water, turned it on and let it heat up. The orange light came on and then went off, which meant it was ready to go. I put some espresso grounds in the portafilter and hooked it on, then flipped the lever to the little “cup” position.

The pump clicked and buzzed and then water started pouring out all around the filter base. It took about two seconds of running to overflow onto the counter and the floor. I got exactly 0% espresso.

So I turned it off, popped off the portafilter, and took a look underneath.

There are four security Torx screws holding the assembly together. I removed those, and then carefully removed the large O-ring with a seal pick. It was in really rough condition. I took it out in the sunlight so I could show it to you. It wasn’t quite split in two, but it was close.

So, a way-too-long search on the internet revealed that the part number is MS-0047037, it’s no longer available from the manufacturer and is also not available from aftermarket appliance parts suppliers. This is surprising to me, since it’s just an O-ring. I measured up the O-ring groove on the machine, and it has an inside diameter of about 54mm. The O-ring itself has a cross-section diameter of a little more than 5mm- maybe 5.2 to 5.4. I’m not exactly sure because I broke my calipers last week (doing something stupid) and haven’t bought a new set yet.

So, I checked out the local hardware and auto parts stores. I found one that “works”, but it’s kind of a stretch. It’s working, and if this was all I could find, I would live with it. I really can’t complain- it was only $1.35 at Bill’s Ace Hardware in Martinez:

With this installed, the machine successfully makes espresso, but you have to tighten up the portafilter way past the “lock” mark. Even then, it doesn’t give you a very cozy feeling that it’s locked into place. The O-ring is either very slightly too small a profile diameter, or it’s a little too soft, or both. I suspect I’d have to replace this again in six months if I decided to use it this way. Once it compresses just a little bit, it’s not going to keep sealing.

…time passes…

Success has been achieved!

I found the correct one at McMaster-Carr. The size is .21″ dia by 2.1″ I.D. by 2.52″ O.D., A.K.A. 3/16 inch width, dash number 330. That works out to 5.33 mm by 53.3mm by 64mm, which matches my measurements way more accurately, and it’s “FDA Approved” food grade. It’s also made of silicone rubber, so it’ll probably never have to be replaced again. The downsides are that it cost a lot more, I had to buy a 5-pack of them, and I had to wait for it to arrive instead of buying it right here in town. It was $16 after shipping and tax and whatnot. That’s a lot for an O-ring, but not a lot to have a working caffeine generator.

I wanted to add one more thing here- it looks like there’s a groove in the mating surface for a second O-ring. Part #MS-0048266 in this diagram:

I think that’s for the single-shot portafilter or for the hot water adapter or something. It’s for something I don’t have and wouldn’t use, so I’m not replacing it. I just wanted to point it out so you know that’s not the one I’m talking about here.

Thanks for reading. I hope this helps someone else fix their caffeine fix, too!