bbirdwell

EDIT: replaced original file with modified file using the Dayco 89130 plastic pulley.

Part number 113-20204-19. Supercharger Drive Belt Idler Pulley. Replacement cost from MB is in the area of $540. I just rebuilt mine for $27.


I pulled the belts off my car, spun the pulleys, and found three with dry bearings; serpentine pulley on the double supercharger drive belt idler pulley, serpentine idler pulley, and the serpentine tensioner pulley. I decided to replace them all but the cost of the above pulley was outrageous. I spent a few days researching and here is my solution.


See attached document for the part numbers and DIY info.

Hope this helps others.


Mod, if it is worth a sticky somewhere, I'd be glad to accept it!



Cross-posted at the other forum.

Hotsauce55

Thumbs up! Who doesn't want to save some cash?

WANTED!!

I'm not running the stock pulley anymore, but very, very nice!!!!!!!

Panduh

wow perfect timing!I needed to do this before the other pulleys show up

Hotsauce55

How did you know? Is it obvious when you pull them off?

bbirdwell

Just remove the belts and spin each pulley. A good pulley is totally silent. A bad pulley sounds like an old roller skate wheel and you can even feel the vibration. Once you hear the dry bearing sound you'll never mistake it for anything else. Silence = good. Noise = bad.


I could have just replaced the bad pulleys but I figured with 90K miles I'd just do them all at one time and be done with it until I put 180K miles on the car....

rockthemullet

If you use Dayco 89130, you don't need to sand it down

Aside from that good work documenting it for everyone, OP

bbirdwell

Just looked it up and it is exactly as you say. If only I'd scanned a little bit further in the catalog....

rockthemullet

No worries, your method works just as well. I'm just glad there are other guys out there thinking outside of the box

Hotsauce55

I was just on rockauto looking for the Dayco 89130 & they reference an outside diam. of 90mm but Dayco website says 89mm. Rockauto wrong or does anyone know if there has been a real change to the pulley size?

bbirdwell

Don't fixate on the 1mm. Depends on if the caliper was on the outside rim, the inside ridges, or if the caliper was held at an angle.


The two pulleys are separate so even if one has a difference in circumference, they do not interfere with each other. You're looking at a difference of 3.1mm in circumference (~1/8") between the two listed numbers.

Hotsauce55

Thanks, just needed some clarity. I suspect the rockauto listing is wrong anyway.

pumpedTSI

Just replaced mine.....its at the back of the motor under the throttle body Y joint.....you will need a long 1/4" drive to remove and replace. Simple job really but removing and replacing the bolt without dropping it is the hardest part.....a magnetic socket helps.....cheap insurance.

Crissus

I'd edit out that PDF and add that Info and re-attach a updated PDF here.
Great Job!

sexyxe

Potentially advice on CPS? Close but not quite the pulley replacement advice this thread is giving.

pumpedTSI

Youre right.....it IS from my CPS change.....not sure how it ended up in this thread.....my apologies for any confusion...

tw2

So 2 years on, just wondering how the bearing has been going in the plastic DAYCO pulley? I saw one amazon review complaining about the bearing. Would it be worth pressing out and throwing away the bearing it comes with and putting in the NSK 6203 ZZC3 straight away?

hayseed

iTrader: (2)

has anyone found a steel replacement other than UPD ? my UPD bearing is wearing out

bbirdwell

I replace all pulleys and tensioners every 60,000 miles (~ 97,000 km) and did so on my last major maintenance. The Dayco was still good after the 60k miles and 40 months of use (but I replaced it anyway).

bbirdwell

I thought the UPD uses the 6203 ZZC3?

tw2

Thanks for that. I will get an oem accessory belt tensioner and the small idler pulley as they are both reasonably cheap. I am still deciding between rebuilding the idlers vs the UPD 3 pulley set. The SC idle pulley has bearing noise, I need to check it properly for rust I think before considering it for rebuilding.

On a side note, the supercharger tensioner is very expensive, my bearing is fine, tension seems ok just the pulley itself is rusting out.

hayseed

iTrader: (2)

it does but for some reason it did not last ,, making noise after 4k miles

bbirdwell

Without pulling one apart, it could be a 6203-2RS was used in lieu of the 6203-ZZC3. The first is rated at 12,000 rpm and has rubber seals while the second is rated for 17,000 rpm, has metal shields, and has greater clearances to allow for thermal expansion. The first 2RS I installed threw out much of it's grease within a couple of weeks of installation; I went back to a ZZC3-rated bearing within a few weeks. No issues with the ZZC3 when I verified it after 5000 miles of use. FWIW.

For grins and giggles I ran the numbers:
Stock pulley diameter equal to 152.4mm.
Circumference is equal to 2 pi * radius equal to 6.28*76.2 = 478.5mm.
Supercharger pulley diameter 90mm.
6.28*45 = 282.6mm
478.5/282.6 = 1.69
6000 rpm redline pulley turning at 10,159 rpm. Lower speed bearing should work fine; I just practice overkill

Jake528

Jake528