Checking out. Good luck.
The bearing can be supported by two sealed cartridge units (6000-2RS) or two "cup and cone" (C&C) bearings. Sealed cartridge angular contact bearings are not normally specified..
The cup is a hardened steel race pressed into the housing, the cone is also steel on the axle and is tightened to the appropriate clearance and secured with a locknut. In the C&C bearing the cups face outward on each side. This arrangement is normally protected by one or more seals, unless it is solely for indoor use in which case it may be entirely open or metal shielded.
The sealed bearings are a a pressed interference fit in the housing and the axle also presses into them. Normally a pair of nuts on the axle are locked to prevent excessive preload.
C5 is greater than normal clearance. I think C1&2 are tighter, whereas C3-5 are looser. "Normal" bearing clearance is therefore a bit tighter than c3 I suppose.
I have previously experienced failures in both sealed and C&C bearings which I attribute to corrosion from water ingress.
My unqualified guess. Open the bearings up and they're rusty.
I'm using both types of bearing in my 'fleet' on different vehicles. My preference is for the tapered C&C arrangement because it uses a slightly larger ball than the 6000 (1/4" vs 3/16).
They never stopped turning but efficiency is very important in this application, power input can be less than 100w.
So, what grease would you use?
Let me make it really simple. Which calcium sulfonate greases have the most corrosion inhibitors, some solid lubricants.
Let me make it really simple. Which calcium sulfonate greases have the most corrosion inhibitors, some solid lubricants.