I ended up with a free Starbuck's Barista espresso machine with a broken pump. It still made noise, but no water pumped. I quickly discovered that a replacement pump can cost as much as $100 online. I figured that I was mechanically inclined and I couldn't break a broken pump any worse than it already was. I've since seen that others have ended up with non-working pumps too. I suspect that a good cleaning will get many pumps working again.
Here's a picture of the business section of the machine after you remove the sheet metal cover. Remove the screws I've got arrows pointing to and the entire lower plastic parts will slide out so you can get to the screws to remove the pump.
I found it was easier to undo the high pressure fitting at the boiler. It did not want to come apart at the pump. I needed to remove one of the electrical connectors connected to one of the witches to get to the fitting easier.
In the picture below, I've removed the pump rubber mounting brackets and fittings along with the electrical connections The red wire goes in the middle connector.
OK, now the pump is out. The main pump mechanism is held into the pump body with two screws. The top fittings will unscrew. Now, it's time to get serious about the teardown.
Here's the totally disassembled pump. There's not that many parts, and they are all pretty sturdy. The main white nylon/plastic section will rotate and come apart. The parts all come apart easily. They can be cleaned with a mixture of distilled vinegar with a little water if necessary. The most likely area to have problems is in the brass section that is exploded in the inset, or in the two pieces marked with number #1. These two pieces should come out pretty easily after the hose is disconnected. When you go to insert the pieces back in, put
the two pieces together like #4 in the inset. This will make sure everything seats properly. In my case the problem area was the brass fixture that I've blown apart in the inset. Click on the picture to see a large version.
The rubber gasket, nylon ball and spring labeled at #2 above all came apart easily. The problem was parts #3 and #4. I couldn't figure out how to get them out. Part #3 can be unscrewed from the brass section. I used a pair of tweezers. A very small pair of needle nose pliers could also work. It can be unscrewed. If the spring doesn't pull out easily, don't pull too hard. You can take a paper clip and push it through the brass fixture to break loose the rubber piece and spring from the brass fixture. That was the problem with my pump. Somehow the rubber piece got stuck. Take all the pieces and soak them in the vinegar and water mixture. Make sure the the rubber and spring are put back together as shown in the inset before reassembling everything. Part #3 does not have to be screwed back in. It can be pushed back in place without screwing it in. It's a one way connector. It has to be unscrewed to take it out, but it can be pushed n.
At this point it's just a matter of trying out the pump. In the picture below I'm showing a setup I'd never recommend. I've connected up the power, put the intake for the pump into a Tupperware container and set the output of the pump into a cup. I'm careful to hold the plastic pieces of the pump with gloves while I test the pump. After I tested it, the pump was pumping lot's of water into the cup. Yea.
At this point, it was just a matter of putting everything back together, trying it out and pumping most of the water reservoir through the portafilter to clean out the vinegar. At this point, I put the sheet metal back on and started the process of becoming a reasonable coffee geek.
If you have questions or issues with this, contact me at "rod (at) myschiffman.org".