I recently replaced the supercharger clutch bearing on my SLK32, and I did so with the help of this video.
It's a video on replacing the E55 supercharger clutch bearing, and it worked fabulously for me. Here's a few tips:
- Torx socket to take off the serpentine belt and to take off the idler pulley bracket.
- Thin needle nose pliers to remove the ring clip holding the bearing in.
- Hose clamp to hold the clutch in place while releasing the bolt. The clamp size is 5". I got mine at Lowe's or home depot for about $5 iirc.
- I bought the NSK bearing, which I believe I read somewhere was OEM (Genuine NSK Bearing PART #32BD45DUM). I specifically used this ebay seller. (Mercedes NSK supercharger Pulley Bearing for C32 SLK32 Chrysler SRT6 | eBay
- To access the area more easily, I removed the radiator fan. It's only held in place by two clips and an electrical plug. It lifts out of its rubber seats pretty easily.
- I also took out the grooved idler pulley and the associated bracket. This made it easy to remove the serpentine belt. When reinstalling, make sure the belt is in place before re-bolting the bracket and pulley.
- The hose clamp didn't impact anything on its own, so I stuck a piece of wood between the hose clamp and a metal part of the engine to stop the clutch housing from spinning.
- The thermal fit technique works really well. I'd done this once before a while ago and used the old pulley and a hammer to push in the new pulley. I think that's why it only lasted another 5 years. Hammering shortens the life of the bearings. I left the parts in the oven/freezer for a half hour.
- I tried to torque the bolt on the supercharger clutch to 40ft-lbs, and I sheared the bolt. It's easy to remove because it's hollow, so I used the needle-nose pliers to unscrew it. I got the replacement bolt at Autozone. It's an M8-1.25 pitch and 25mm long bolt. The second time around I just made it tight.
- I also used brake cleaner to clean the parts while they were off the car.
- While you're in there and the serpentine belt is off, you may consider replacing the idler pulleys as well. I replaced the one on my tensioner (same as the other idler pulley), and should have replaced the other two as well.
This reduced a lot of noise, so for $50 and a bit of sweat, I'd say it's totally worth it.