Rancilio Rocky Grinder - Separating Chamber from Rotor Shaft

Equipment doesn't work? Troubleshooting? If you're handy, members can help.

#1: Post by DnstrDan » Oct 12, 2019, 7:51 pm

Yesterday, my Rancilio Rocky made a pronounced oscillatory sound that it had never done before. Today, it failed. The motor still labors when I pulse it on, but barely turns. (This failure was likely induced by me when I applied a small amount of Cafiza cleaning solution to the grinding chamber to clean it out. Won't do that again.)

So I took it apart as far as I could go. I lifted the rotor from the motor stator assembly, then from the grinding chamber I removed the circlip and three washers underneath. I can twist by hand the chamber against the rotor but there is considerable stiffness and binding.

What is the proper way to separate the grinding chamber from the rotor shaft? I'm tempted to use either a hammer and drift pin on the center shaft, or a bearing pusher/puller that I'd rent from a local auto supply shop.

And should I scribe the alignment between the two parts for dynamic balancing upon reassembly?

Supporter ♡

#2: Post by ira » Oct 12, 2019, 8:44 pm

I never took mine apart, But this person did and maybe there are hints in this thread:

How I aligned my Rancilio Rocky.



#3: Post by DnstrDan » Oct 13, 2019, 1:47 am

Ira - thanks for the lead to the post by coffinnate, but he didn't explain how he removed the grinding chamber from the rotor shaft.

I think this post provides more tips: Mazzer Super Jolly bearing removal tricks: My grinder rebuild

I'm honestly surprised that no one has posted on this topic before. Not many folks apparently tear their Rocky completely apart.


#4: Post by DnstrDan » Nov 03, 2019, 4:00 pm

I decided to look for an electric motor repair shop close to where I work. Motor and grinding chamber in hand, I stopped at ABCO Electric Motors in Los Angeles. I unexpectedly discovered that Intelligentsia's L.A. Roastery shares a common wall with their shop! I took that as a good omen for the visit. Image
They quickly disassembled and replaced both top and bottom bearings with stock on-hand Koyo 6201RD sealed bearings. (The OEM bearings were 6201-RS (sealed, top), and 6201-Z (shielded, bottom). Image
For those who are interested, here's an excerpt from Koyo's standard bearing catalog with the pertinent technical details.
This shop is old-school and mostly services large industrial electric motors. It was fun to watch the craftsmen at work while I waited; it took all of 20 minutes and a flat $30 cash for parts and labor. It would have cost me three times as much to DIY after tooling up, so I was really pleased. One piece of advice I got was to run a bead of Krazy Glue along the outside circumference of the top outer bearing race before sliding the grinder chamber back into place, with the admonition that I need to be quick about it.

Back at home on the weekend, I reassembled my Rocky and went through quite a bit of beans dialing it in. The repair was successful, but needless to say I disturbed the factory alignment. On my next holiday break I'm going to apply a stepperless adjustment mod, and re-align and shim it as needed.

All in all, very pleased with the low-cost bearing replacements, particularly after a well-known L.A. espresso machine repair shop essentially told me that my Rocky wasn't worth fixing.