Hendrik Koster

I removed the alternator from my S65 and removed the voltage regulator to check it out.
Attached are the pictures showing why it was no longer charging the system. I could fix it, but opted to replace it with a new unit.

I'll add more pictures later describing the alternator's removal process for those.





interested in going along at home.

Best HK

kafklatsch

I recently replaced my regulator after xentry revealed that the alternator was mechanically sound. Based on your pics, you did not have a regulator brush issue, which it what usually goes bad with the regulator. your brushes still had many thousands of miles left. My brushes were sticking out about 2-3mm (<1/8")

In your case, the rotor contacts (shaft contacts) are in really bad shape and requires and alternator replacement ( or major rebuild). Those same rotor contacts in my case looked like new with only the graphite brush grayish substance on them, which I was able to remove with alcohol and a spin. There was zero scoring of the copper contact surface. I am surprised your rotor contacts look that way, but it depends on miles and driving environment it seems.

your decision to replace the alternator was correct.

by the way, i was able to replace the regulator be loosening the belt tensioner, unbolting the alternator, and removing the bottom splash shield. the alternator was free to be rotated and moved just enough to replace the regulator without the longer more tedious alternator removal procedure, which involves fan removal, radiator removal and other work... some of the work space is tight, but I told myself to be patient in the tight space, as I was saving a ton of alternator removal work and time.....w222 S550 in my case... my AMG is low miles and still fine...

good luck..