Mazzer Super Jolly bearing or motor issue?

by **RLeS** on Sun Dec 19, 2010 10:53 am

Hello guys,

Glad to be posting on the HB-boards for the first time - I do love this website! Too bad the reason is not as lovable..

Please, first watch this video to get an impression of the problem.

Issues

Rotor spins down in under two seconds.
When the motor runs, a loud noise can be heard. The longer the motor runs, the louder the noise. I have to switch off the machine, or else it sounds like it will explode...

Possible causes

Friction between rotor and stator.
Damaged bearings. Could be the reason why the noise and vibrations get worse over time (about 5 seconds).

Additional info

I removed the doser, stripped the paint, and polished the body.
I removed the doser microswitch according to these instructions. Everything worked fine afterwards.
In the video, the burrs have been removed. They are not the cause of the noise!

Before visiting a repair shop, or trying to fix it myself, I'd like to be aware of the possible causes. Any help would be appreciated. Thanks a lot!

Regards,

Raoul

by **JohnB.** on Sun Dec 19, 2010 11:15 am

Sounds like you need to change the bearings as I doubt the grinder would run if the rotor & stator were contacting. Plus for that to happen one of your bearings would have to pretty much fall apart. If you have access to a press changing the bearings isn't a big deal. The bearings are common & cheap. I bought mine at the local Napa.

by **RLeS** on Mon Dec 20, 2010 4:49 am

Thanks for your advice. It must be the bearings indeed. I was just afraid that it could be something worse since the problems started so suddenly...

I read many pages on removing the rotor of a Mazzer, so I know what is needed. Too bad access to a press isn't that straightforward. Professional repair on the other hand would be a bit too expensive.

When I find a solution I will update this thread, hopefully with some pictures.

by **godlyone** on Sun Dec 26, 2010 1:16 am

a sledge hammer does the job just as well as a press - just be sure to hit through a piece of wood or something

by **darilon** on Sun Dec 26, 2010 12:25 pm

I'm sure there are many local machine shops you could pay a small fee to and they would have a press.

by **olive** on Thu Feb 03, 2011 11:43 am

What's the best/easiest way to remove the old bearings (do i need a 3-jaw puller)? will i find two sets - one at the top and bottom of the motor? does anyone have instructions or a guide for doing this?

by **duke-one** on Thu Feb 03, 2011 3:34 pm

Most bearings need to be removed with a puller. It is easy to ruin new bearings by improper installation, a bearing heater or a press is the proper way to install small bearings. Have the machine shop do it, they will last. When you have the armature out rotate the bearings by hand if they are shot you will be able to feel roughness in them. From the sound on your video I'd be you'll be able to feel the lack of smooth rotation by hand. Compare the feel of the new bearings to the old.
KDM

by **randytsuch** on Thu Feb 03, 2011 4:05 pm

At some point, I had a SJ with noisy bearings. I considered changing them, but ended up selling it (with full disclosure) fairly cheap. I never heard back from the buyer, so I don't know if he changed the bearings or not. It seemed to work fine, but was noisy.

I did some research back then, and remember finding posts about someone heating up a SJ in an oven, so the chassis expanded, and then the motor and bearings would pop out fairly easily.

Randy

by **JohnB.** on Thu Feb 03, 2011 4:25 pm

You only need to remove the rotor so there is no need to heat the entire grinder as the stator is not touched. I used a hydraulic press to press the rotor shaft down & out of the upper bearing race. Others have placed a block of wood over the upper end & tapped the rotor shaft out of the upper bearing.

The lower bearing sits in the rotor retaining cover accessible from inside the grinder. If you are lucky the bearing will stay on the lower rotor shaft when you remove the cover as it can be easily removed from the shaft several different ways. I'd suggest heating the center of that cover before removing it to help insure that the bearing does not come off with the cover. If it does stay in the cover there is no room for a blind puller & you may have to drill a couple 1/8" holes through the bearing cup portion of the cover so you can drive out the bearing with a drift.

Once the rotor assy is removed from the grinder you can easily drive out the upper bearing from underneath with a suitable drift.


Contact Us	Legal disclaimer and copyright: This content and all its parts are copyrighted, all rights reserved. Content including all text and images in part or in whole may not be reproduced in any electronic or printed medium without prior permission. Home-Barista, Home-Barista.com and related logos are trademarks of Home-Barista.com, LLC. Other trademarks are the property of their respective owners. By accessing this site, you agree to the terms of service. Overall speed: , current page: s, avg: s, max: s