Breaking a bolt is very easy to do, they're only 4 mm. Trying to remove the broken bolt with a #1 extractor bought at Lowe's first requires drilling the bolt w/ a 5/64" drill bit for a pilot hole. Well the drill bit broke, cut my finger and I'm gonna buy a replacement. The grinder was bought on fleabay and was never cared for, completely caked with stale grounds every place. I did bring it to a shop to get the lower burr screws removed it was so bad. Lesson: don't buy on fleabay w/o actually seeing what you're getting.

Marvin

First, just wanted to say thanks for this thread. I'm rebuilding a Super Jolly, including the internals, and have the housing out for powder coating right now.

I just purchased the two replacement bearings, model 6202. When I was removing the bearings I noticed quite a bit of grease. Was wondering why they were greased? I was told since these are sealed bearings, they should never need to be greased on the outside. Was this grease there to prevent rubbing between the shaft and the bottom base?

Just trying to figure out if it's necessary to re-grease the new bearings before installing.

Thanks!

It isn't necessary to regrease the new bearings but if they have removable plastic/rubber shields I always do. Typically I find very little grease inside & what is there isn't very good. I clean them out & repack with a high quality high temp bearing grease.

There is no need to apply grease to the external surfaces.

JohnB, thanks for the reply. I'm a little confused here... The bearings I purchased are fully shielded, enclosed. I actually wasn't able to get the OEM ones (SFK I believe they were) but ended up getting Nachi, which I understand are very good quality. I don't plan to open them up, if that's what you're saying.

I'm asking specifically about the grease that was found on the bottom base plate, in the bearing notch. See picture here for a visual of what I'm talking about:



I am guessing that the original grease was applied to prevent rubbing between the inner ring of the bearing and the base plate during operation, but that's just my guess. (This is the first time I've played with an electric motor.)

Is it necessary to re-grease the baseplate notch? If so, what is a good hi-temp, hi-quality bearing grease? Would something like this work: http://www.directindustry.com/prod/skf- ... 27714.html

It looks like the original grease is thick, reddish in color. Does the SFK stuff linked above have the same color/consistency?

Thanks!

As I said before there is no need to apply grease to the outside of the bearing. It isn't going to move inside the bearing cup/bottom cover. The grease you found could have come out of the bearing itself if it was over packed or got hot??

I've refurbed 9 of these old Mazzers so far & haven't found grease in that location on the ones I tore down that far.

As far as the shields go if they are metal you can't remove them but if they are plastic they can be popped off & snapped back on. I'd be more concerned with the grease that's inside the new bearing (how much?/how good?) then what you found on the outside of the old one.

+1 to what John said about grease.

The grease you found in the seating area of the end bearing is probably from the bearing either getting hot or from a failed grease seal (which could also have been from heat). Otherwise, it was from a previous owner who heard a noise and just squirted some grease n there thinking it might do some good.

Great, I will clean out the bearing cup before seating the new bearings in there. Upon taking apart one of the old bearings, it has the same type of grease (color, consistency) as what I found in the cup so I think you're right--must have been from the bearing.

After a herculean effort involving a bench vice, a large crowbar, and a hammer, I was able to pull the second (bottom) bearing off the motor shaft. I essentially had to destroy the bearing in the process, ripping the outside of it off and exposing the bearings and grease. No worries, I planned to toss the old ones anyway, but this concerns me... How the hell am I going to get the new bearings on there without damaging them in the same way?

I'm not so concerned about the bottom bearing, since it's relatively easy to just hammer into the cup and then hammer the motor into that, but I'm not sure how I'm going to get the top bearing to slide down the shaft and into the top cup once the motor has been put into the housing... Without totally manhandling it and either damaging the bearing or the shaft.

Any advice? I'm not quite to this step yet but I anticipate it will be troublesome. Can I heat the bearing, or are there any other tricks that will make sliding it on easier? Or should I get a machine shop to press it on?

Or am I doing about the re-assembly process in the wrong order?

Thanks!