What generally fails on the airpump that produces an awful bearing grinding noise?

Any MB quality rebuilt units available?

tks-fad

The bearings on the pulley shaft themselves...

...in some cases they will seize up causing the pulley to lock up and shred the serpentine belt.

Rebuilt pumps are available from various sources as the bearings themselves are not readily available. This may be more of a deterrent for a DIY'er wanting to rebuild the pump since it is a smog-related component.

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2009 ML350 (106K) - Family vehicle
2001 CLK430 Cabriolet (80K) - Wife's car
2005 BMW 645CI (138K) - My daily driver
2016 Mustang (32K) - Daughter's car

thanks G-Benz for the info!
-fad

I don't know if it applies in the MB case, but the typical cause of air pump failure is a bad check valve allowing hot exhaust to backflow into the pump. Replacing those at the same time is good practice.

Steve

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'91 MB 190E 2.3
'08 RAV4 Ltd 3.5
'83 Lazy Daze m'home 5.7