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Hi All,

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:



TOOLS:
- 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.

PARTS ($50):
- 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)

TIPS:
- 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.
 

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Registered SLK32 AMG 2002
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Hi, replying to an old thread but it seems the most relevant place to ask.

The supercharger on my 2002 SLK32 AMG which has done 124,000 km is a bit noisy.

This was confirmed by the Mercedes dealer who quoted $4593 (!) AUD to replace the entire supercharger assembly.

Based on this post and the video above, I bought the NSK bearing that goes inside the pulley and had a mechanic install this, hoping this would improve the noise.

It doesn't seem to have made a big difference and the mechanic thinks that the pulley itself is a bit worn and needs replacing.

Problem: The pulley does not seem to be available as a part on its own from MB?

There only seems to be part number 112-090-00-80-80 which is the entire supercharger incl. pulley as one item.

There are smaller pulleys available on eBay which are supposed to increase performance, e.g. listings like this one which are 65mm instead of the standard 73.6mm AMG pulley: MERCEDES AMG C32 SLK32 Chrysler Crossfire SRT6 SRT-6 smaller supercharger pulley | eBay

However I'd really prefer to stick with the stock size, the fuel economy is bad enough as it is and I really don't need the car to go any faster.

Any pointers?

Is it at all possible to get a new standard size pulley from Mercedes as an individual part or does anyone produce standard size replacement pulleys?
 

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Administrator 2009 SLK 55 AMG/Founding Member 2006
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Hi, replying to an old thread but it seems the most relevant place to ask.

The supercharger on my 2002 SLK32 AMG which has done 124,000 km is a bit noisy.

This was confirmed by the Mercedes dealer who quoted $4593 (!) AUD to replace the entire supercharger assembly.

Based on this post and the video above, I bought the NSK bearing that goes inside the pulley and had a mechanic install this, hoping this would improve the noise.

It doesn't seem to have made a big difference and the mechanic thinks that the pulley itself is a bit worn and needs replacing.

Problem: The pulley does not seem to be available as a part on its own from MB?

There only seems to be part number 112-090-00-80-80 which is the entire supercharger incl. pulley as one item.

There are smaller pulleys available on eBay which are supposed to increase performance, e.g. listings like this one which are 65mm instead of the standard 73.6mm AMG pulley: MERCEDES AMG C32 SLK32 Chrysler Crossfire SRT6 SRT-6 smaller supercharger pulley | eBay

However I'd really prefer to stick with the stock size, the fuel economy is bad enough as it is and I really don't need the car to go any faster.

Any pointers?

Is it at all possible to get a new standard size pulley from Mercedes as an individual part or does anyone produce standard size replacement pulleys?
Always better to start a new thread for more views
Let me know if you want me to move it to its own new thread
 

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Registered 2002 SLK32 AMG
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I concur with the above... don't be afraid of having to go with a smaller pulley. The supercharger is a part-time system, and with all V6s (not just MB) being fuel inefficient to begin with, your mileage really won't change. In fact, if you decide to go a small step further with a proper tune, you'll actually gain a bit of MPG under normal driving conditions... after that, the performance pulley being cheaper to boot is just icing on the cake!
 

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Registered SLK32 AMG 2002
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Thanks for the replies. Does this 65 mm pulley from Poland seem like a reasonable choice?

MERCEDES AMG C32 SLK32 Chrysler Crossfire SRT6 SRT-6 smaller supercharger pulley | eBay

I recall reading a horror story where a 3rd party pulley came apart and damaged the engine, so I'm a bit wary.

Also, someone else I spoke to online thinks the noise could be caused by rear bearings inside the supercharger, which can be bought cheaply:

https://www.ebay.com.au/itm/Mercedes-C32-Slk32-Crossfire-SRT-6-supercharger-rear-bearings-A1120900080/142676377447

Thoughts on this? My mechanic is fairly sure the main pulley being worn is the cause of the noise.
 

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Registered 2002 SLK32 AMG
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233 Posts
I've heard good things about the Polish pulleys from others, and the important part is that it's made of steel.

The failures that were going around for awhile was when companies (such as Eurocharged) switched from offering oversized crankshaft pulleys to undersized S/C pulleys. The old style S/C pulleys were being made from aluminum to save on rotational mass, however they weren't strong enough to withstand the belt tension coupled with the shock of the pulley clutch when it was activated, so this led to them cracking and failing spectacularly.

As mentioned above, the rear supercharger bearings can be replaced as your choice, or if the pulley still fails to fix the problem. However, I am of the mindset that every 32 on the road should have a pulley upgrade anyhow, so if it does turn out to be bearing noise it won't be a total loss :grin:
 

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Registered SLK32 AMG 2002
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36 Posts
Thanks for the replies.

I found out that the original spec pulley is in fact available separately from Mercedes as part A1120900044 but Mercedes-Benz in Melbourne, Australia quoted 3700 AUD (!) for the pulley only.

It's listed as "Supercharger Flange Repair Kit" elsewhere and available cheaper overseas but still very expensive.

I think I will go for the Polish 65mm pulley option and maybe have the rear bearings + supercharger oil replaced as well, depending on how much my indy mechanic will charge for the labour.
 

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Registered SLK32 AMG 2002
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36 Posts
Is a tune essential if I change from the stock to a smaller 65mm pulley? Or should mappings adjust automatically?

As I mentioned, I'm not really looking for higher performance, the smaller pulley is just the only reasonable priced option for getting a new pulley that will run quietly.

I'd rather want good fuel economy rather than highest performance, the car is fast enough as it is.
 

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Registered SLK32 AMG 2002
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Any thoughts on what is causing the quite noticeable noise from my SLK32 AMG v6 supercharger or engine while idling?

At least some of the noise seems to be coming from the pulley at the front:


N.B. the bearing inside the supercharger pulley has already been replaced with a new NSK one but this did not improve the noise situation.

The mechanic thinks the pulley itself is worn and needs to be replaced, hence I have ordered a 65mm pulley from DTK (+ECU tuning kit) which will hopefully improve the noise and also give a performance boost as a bonus.

I have also ordered new rear bearings and supercharger oil from www.benzperformanceparts.com.au which the mechanic will install at the same time.

Do you guys think replacing these parts should fix the noise or could it be something else entirely (or as well)?
 

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Administrator 2009 SLK 55 AMG/Founding Member 2006
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96,648 Posts
Serpentine belt, if old, cracked or missing a piece will throw off the sc activity
check idler pulley?

That is all! :D
 
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