bearing specs for MM16 upper wheel?

[David Zaret]

my MM16 has bad bearings in the upper wheel. it sounds as though i'm trying to cut gravel. does anyone know the specifications of those bearings? thanks.

[Bill Dufour]

I would think are just regular M3 class with rubber seals.
Bill D

[Erik Loza]

David, that info should be stamped on the bearing face. A PN or something. Ought to be visible without pulling anything apart. I would go for SKF or Nachi brands as replacements. You will need a three-jaw puller to remove the upper wheel, by the way.

Erik

[David Zaret]

i was able to get the wheel off, exactly as you suggested. no issues. now, i have two bearings, one on each side, with a spacer in the center. do i have to pull each bearing out each side? or, does the bore go all the way through, and i can bang the whole stack out one way? both snap rings are off.

thanks!

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[Bill Dufour]

I would assume they only come out one way. Look for a snap ring that has to be removed before pulling them out. One may be a bigger then the other.
The id number should be a four digit number. I can not quite read it on the seal face.
If the top bearings are bad I would guess the lowers are close since they have seen equal service life. Not really needed since removing the top bearings does not help for the lower one at all and vice versa.
Bill D
Bill D

[David Zaret]

snap rings on both sides. both are removed. the parts diagram shows that the center bushing is smaller in OD than the bearings. this is why i'm concerned that the cast iron has center ridge....

[Jerry Bruette]

I'd assume the bearings aren't seated against shoulders if there's a center spacer. The spacer would ride against the inner ring of the bearings and should be smaller in diameter than the outer ring of the bearings.

If you have a socket or piece of pipe, etc. that would be slightly smaller than the outer ring give one bearing a tap with a hammer and the opposite bearing should move. If it does drive it out, remove the spacer and drive the remaining bearing out the other side.

[Bill Dufour]

Note that wood or pvc pipe or coupling may be strong enough to shift the bearings.
Bill D

[Brian Holcombe]

My MM20 bearings were in a bore without shoulders. I drove them out in one direction with a block of wood as a drift.

I replaced the original bearings with SKF Explorer.

[David Kumm]

SKF explorer are a good choice. Normal or C2 clearance. Not C3. Dave

[David Zaret]

My MM20 bearings were in a bore without shoulders. I drove them out in one direction with a block of wood as a drift.

I replaced the original bearings with SKF Explorer.

excellent. do you have a preferred bearing source? thanks guys.

[Jerry Bruette]

Any industrial supply store. Motion Industries or Fastenal could supply them.

[Bill Dufour]

VXB in Anaheim is good enough for most bearings. Depending on how hard it is to replace and how long you will keep the tool better quality may be worth it to you. Beware there are many counterfeit named bearings out there.
Bill D

[Brian Holcombe]

David, I use McMaster Carr.

[Bill Dufour]

Ignore my class number recommendation I was confusing class# vs ABEC #. The other posters have it correct. No need for super precision bearings.
Bill D.