When I replaced my alternator a few days ago, I noticed allot of red dust under the AC compressor shield and on the compressor itself.

Is this a sign of a bad bearing?

Red dust probably came from the failing alternator.

The red dust is the same red dust that you see around your brakes and such. It is the result of the proper function of the clutch and the wear of the friction materials in the compressor clutch. Don't worry about it. Eventually the clutch will fail with the loss of enough friction material. But you aren't seeing anything unusual or worrisome.

Red dust probably came from the failing alternator.

 

It wasnt on the alternator or its shield, just the compressor sheild.

But you aren't seeing anything unusual or worrisome.

 

Thanks

Lotsa red dust under mine on my '03, and even a good bit on my wife's '05 forester with about 45Kmiles.

 

 

Dave

maybe the ac clutch?

maybe the ac clutch?

 

Yes, I believe that's exactly what I said.

it could be rusty, hence bad bearings still being used produces red dust (rust).

Cheers

AP