I'm starting to research what is involved with this repair. The car has a scary sounding rattle at cold start up but noise abates while driving.

From what I gather a partial rebuild of the pulley end of SC could solve the immediate problem but there are many parts that will eventually need attention. Full rebuild would involve the rear needle bearings (doesn't sound easy), front bearings and clutch. With all this, it sounds like any partial rebuild is short sighted and you might as well put in a factory rebuilt and be done with it.

Prices seem all over the lot. A local rebuilder has them at $1400, $2250 for a brand new OEM. My regular parts guy claims he has OEM from Mercedes for $1500. Front end rebuild kits on ebay with coupler and bearings are about $60.


Has anyone successfully done a partial/full rebuild of what I believe is a Eaton M62 supercharger?

Are you sure the noise is from the supercharger?

Have you checked the oil level in the supercharger?

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I just went through with these issues on my C230 last December. The rear needle bearings are actually very easy to replace, just press-in the new bearings and re-grease and your good to go.

In my blower I could detect no play in the front bearings but the rear needle bearings were shot, its pretty easy to tell because there should be virtually zero free-play in the rotor lobes, certainly none that you could detect without a dial indicator.

I was planning on replacing the rear needle bearings but I ran into problems sourcing the correct bearing. Apparently there are a couple of different ID/OD dimensions on different version of the M62 blower. I did manage to get what I think is the correct set on the 3rd try but when I re-assembled the rotor lobes I found that I had contact between the lobes at certain points. After some further reading I found out that sometimes machining of the lobes is required after bearing replacement.... at this point I decided I was over-my-head and decided to box the whole thing up and have it rebuilt by a professional. I used Embree speciality machine in Missouri - they did a great job and as I recall it was around $600?

Another issue is the electro-magnetic clutch. The bearings are available but the flex-plate on the front of the clutch wears out at the point where the rivets attach the friction surface to the spring-steel external face. On my clutch this was the only problem but I was unable to find a source for the flex-plate, I ended up replacing the entire clutch assembly because I wanted it 'right'. MB seems to be the only source for the clutch and it was around $450 if I recall. So in short I ended up paying around $1,000 for a virtually new blower/clutch assembly.

I saved $500 over the cheapest remanned unit I could find but the car was out of service for the better part of two weeks while I coordinated all the activities associated with a re-build. I could see someone paying an extra $500 to avoid all the hassles of what I went through and have the car back in service in one day.

My car had 170K on the original blower and it was making quite a racket, after the rebuild its 99% quieter.

Another route to go is to try to find a used lower-mileage unit, two weeks after I completed this whole process I actually had a used M62 from a SLK show up in a car transaction. It's supposed to be from a 40K mile car that had supercharger issues and was replaced by a local MB dealer under warrantee when the clutch went bad. I have no way to verify that story but the bearings do appear to be in good shape. I can't guarantee it but I'd sell it to you for $150 if you wanted to take a chance on it, PM me if interested.

Good luck, its not that hard a process but it does take some time.

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My son is bringing the car home next week. I have not checked the oil level. I do need to confirm that it is the SC that is making the noise but from what I remember there is a rattle at startup that goes away at speed.