Alternator clutched pulley bolt question

timsch

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I finally got my clutched pulley, the Gates 37010P Alternator Pulley Kit

It's called a kit, but all I received was a single piece, which is the pulley shown in the picture of that link.

Is there a special bolt that I need to have to swap my original alternator pulley with this one or do I use the original bolt?

thanks
 

timsch

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thanks for the info. I was puzzled by the threads inside of the pulley. Makes sense now.
 

markd89

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Clarifying questions:

Here is my current alternator pulley - 97 Passat 1Z setup.




I'm going to go with the clutched pulley setup of the Gates 37010.

From reading a bunch of threads, it seems like I need a 10mm triple-square socket to go into the splined area. I'd use this as a counter-hold while I use a regular wrench to remove the nut in the normal counter-clockwise direction.

Is that correct?

Thanks!
Mark
 

timsch

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You won't be able to get a "regular" wrench inside the pulley. I ended up just using a pipe wrench on the pulley once I removed the belt as I loosened the nut with a socket. I didn't put the pipe wrench on the section that the belt rides on in case I needed to reuse it for any reason. I sprayed Liquid Wrench inside the pulley and let it sit for a few minutes before trying to take the nut off. It came off fairly easily with minimal wrench marks on the pulley. I'd do it that way again.
 

TDIJetta99

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I pop it off with the impact gun... no need to even hold it lol... the nut comes right off...

If you don't have air tools, holding the pulley with a pipe wrench works pretty good as well as previously mentioned

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markd89

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Thanks guys, I'm going to visit the "shop" for this one, so will have air tools. To put the new pulley on do I just reverse the process (i.e. use the impact gun)?

That nut is normal not reverse thread, right?

Thanks again!
Mark
 

TDIJetta99

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It's normal thread.. just thread it on by hand, then put the belt on and start the engine. The load from the alternator will tighten the pulley immediately.

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TonyJetta

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For future reference, you will need the metalnerd alternator tool bits to remove the pulley.

Tony
 

markd89

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For future reference, you will need the metalnerd alternator tool bits to remove the pulley.

Tony
I see, said the blind man ;-)

Maybe I was unclear originally but confused again now...

I'm looking to replace the pulley. So I need to remove the nut and pulley and install the new pulley and nut.

It sounds like I can use an impact wrench to remove the nut, but I need the triple-square 10mm to counterhold the shaft while I somehow remove the pulley. I think I'm still missing something?

Mark
 

TonyJetta

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I'm looking to replace the pulley. So I need to remove the nut and pulley and install the new pulley and nut.

It sounds like I can use an impact wrench to remove the nut, but I need the triple-square 10mm to counterhold the shaft while I somehow remove the pulley. I think I'm still missing something?

Mark
Mark,
Sorry for the confusion.

Yes, use an impact to remove the original, fixed, pulley. That's how I removed mine.

In the distant future, you will need the metalnerd alternator bit set to remove the clutched pulley.

Tony
 

markd89

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Mark,
Sorry for the confusion.

Yes, use an impact to remove the original, fixed, pulley. That's how I removed mine.

In the distant future, you will need the metalnerd alternator bit set to remove the clutched pulley.

Tony
Got it. And to further make sure the horse is beaten -- I can install the new clutched pulley without the special tool?
 

TonyJetta

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Got it. And to further make sure the horse is beaten -- I can install the new clutched pulley without the special tool?
The new pulley just threads on to the shaft.. No nut or anything.. Just thread it on and go..
To add a little more beating to the dead horse...and to reword what TDIJetta99 said, the tension of the serpentine belt pulling on the pulley should torque it to the shaft.

Tony
 

uturn

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so what is the function of the clutched alternator pulley? Never seen that before. I know the alternator has a clutch on it, but never seen one on an alternator. Sorry ahead of time for my possibly dumb question
 

G60ING

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I've heard that its to help reduce stress on the crank cog
 

TDIJetta99

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03... Faster than yours =]
Ya it reduces stresses on the belt system.. You can see right away with the diesels if the clutch fails.. The belt tensioner hops all over the place while idling.. Nissan has been using clutched pulleys for a wile now too..
 

TonyJetta

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I've heard that its to help reduce stress on the crank cog
That's the result.

What is happening....
As each cylinder fires, the crankshaft accelerates. As each cylinder compresses air, the crankshaft slows down. This acceleration/deceleration is what causes belt chirping, harmonic balancer wear, and wear on the crankshaft snout. A major contributor was found to be the mass of the alternator stator and it's inherent unwillingness to speed up and slow down (known as moment of inertia).

By installing a clutched pulley, the alternator is allowed to speed past the slowdown event of each cylinder compressing air. The greatly lessens the impact of the alternator on the accessory drive, reducing or eliminating the damage to the crankshaft and the timing pulley.

Myself and others have noticed greatly reduced oscillation of the serpentine belt tensioner arm after installing the clutched pulley.

Tony
 

clyde

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On the Bosch alternators used on Mk3's, is the alternator shaft threaded right- or left-handed?

I'd guess right, because the torque from the belt would tend to tighten instead of loosen the pulley…

Right?
 

TonyJetta

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I'll see if I can find my original pulley nut later this morning.

Tony
 

Biczek

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According to the Gates catalog the 37010P pulley width is 40.5mm and outside diam. 50mm

My original looks like width is about 37mm and outside diam. 55mm.

The Gates 37011P width is 37.5mm and outside diam. 55.5mm

Did You guys check size of the original pulley on your alternator?


Tom
 
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