Bearing missing its cage?

[indykid]

SWMBO's CR-V started making an odd noise this afternoon. The AC pulley was intermittently rattling and squawking. You could see it wasn't running true, then it'd shudder and have a bit of a gallop before settling down again for ~15 seconds.

I've had it in bits this evening, the bearing felt ok but sounded like crap, but I knocked the pulley off (not trivial in itself) and pulled the inner seal to see if it wanted some grease. It's a special looking double row ball bearing but inside, there were no cages on either side. It looks like it might have been a polymer cage if anything, but there's not enough debris inside to convince me that there ever was a cage.

My question is......is this normal? it's not like any bearing I've ever seen before but I can't find a datasheet to see what it should look like. If the balls aren't evenly spread though, it would explain the movement and vibration in the pulley

I've given it a lick of grease, popped the seal back in and put it back together to see how it went and it seems happier, but I've left the clutch off for the time being so it's just running as an idler. The inner race isn't precessing so I'm not too concerned about it doing any damage to the compressor housing. I'll look to order a replacement pulley/clutch since the clutch has already had the shim stack reduced a couple of times, but I'm now wondering how close it is to grenading and whether I should send the boss to work in it....

 

[Trevorleach]

I would say that is knackered.

 

[Pete.]

You can get full compliment bearing but that one has just lost its cage.

 

[RichardM]

Looks like some of the bearings and the cage are missing, are those the actual bearing or being used to balance it? Any numbers on the bearing?

 

[indykid]

Thanks for all your thoughts. It's given me a lot to ponder.

The bearing number is NSK 35BD4820DUM6 by my reckoning but I only have the number on the seals, not the races. It's 35mm id, 48mm od, 20mm thick so it appears to directly reference its dimensions, I'm just not sure on the prefixes and suffixes.

The NSK catalogue shows their double row bearings with polymer cages so I suppose that's probably what the black band behind the balls is, but this aspect ratio isn't a catalogue size. I hadn't considered a third row of bearings, but I suspect that's possible given the axial space available. I didn't dig too deep while I was in there but I'm keen to cut this one up once the new one arrives!

I still don't think there's enough debris inside the seals for it to have eaten the cage and the continuous band of black behind these balls would stand to reason that it's the rim of a cage which would have to press in from the outside. There's practically no slop it, which I would expect if the balls weren't evenly distributed.

 

[indykid]

I would say that is knackered.

An astute observation. First prize to you.

Just 2 rows of bearings as I expected. The black band behind the loose balls was melted cage that had stuck back together. The races and balls still look good under the microscope but the cages are....disappeared both sides.

Should anyone find this thread in future from the bearing number, the bearing balls are 4mm diameter, fyi.The thermotec KTT040153 clutch kit all fits OK on a sanden trse09 compressor on a 2009 CR-V, but the clutch needs about 3mm of spacer so the nylon ring on the compressor nut doesn't engage, but it's still got about enough threads remaining comparable to a plain full nut so gave it some loctite 243 nut lock, some setting marks visible from the top and I'll keep an eye on it.