Check your Top Pulley & Alternator

[StuF]

Hi fellas,

Following our trip I have been planning on doing some rectification work on the bus, started up fine today and reversed out of garage.
Once I was in the sunlight I noticed the fan belt was loose and upon further inspection and removing the top pulley and belt I found the rear of the pulley has been cutting into the alternator.

This friction has caused a number of the shims to shatter causing the belt to go slack and the woodruff key to get mullered nearly failing. Has made a right mess of the cutout on the alternator shaft.

My question is - whats the order of fitting the parts?

Should there be some sort of spacer before the rear of the top pulley is fitted against the alternator as it is physically cutting a groove into it.

At the moment I have

Alternator - Rear of Top Pulley & Woodruff key - Shims to tension belt - Belt -Front of Top Pulley - left over shims - Top Pulley Cap - Top Pulley Bolt

I have had nothing but issues with the top pulley since owning the bus and would like a definitive answer please.

Here are some pics to illustrate the problem I have

Pic of the alternator when the top pulley exploded on the way to BusFest - take note of the woodruff key cutout and the lack of scoring on the face of the alternator



Pic of the same alternator today after removing pulley - key cutout is mullered and the scoring on the face is much worse







Pic illustrates the rear of the top pulley where it was making contact - normally I like shiny bits!



Shattered shims



Woodruff key all twisted and bent





Any ideas?

 

[StuF]

Anyone? Are you all at EBI or Glasto?? :?

 

[StuF]

Anyone know what the arrowed part is????

Might be a spacer I am missing?

 

[vwvanman0]

There looks to be a spacer like the one arrowed on your alternator already,it looks like the pulley nearest the alternator is only held away from the alternator by the shims and when its tight the shims are bending/destroying themselves which leaves the pulley free to cut into the alternator,

Don't think you should have shims between the alternator and the rear pulley,they should be between the pulleys to adjust the belt tension and the spares go on last under the washer and nut.If you need shims between the alternator and the rear pulley you may have the wrong pulley? With no shims on does the pulley clear the alternator? if it does'nt,i think its the wrong pulley.

You can get the alternator welded up,just undo the screws and take the damaged bit off,(did this when my rear pulley broke and gouged mine worse than yours) also if you remove this you will see if the collar on the alternator is a spacer.

 

[StuF]

Cheers for the response mate - how can it be the incorrect pulley? There only seems to be one type available.
The pulley clearly needs a couple of mm spacing out to stop it fouling the alternator. Fitted on its own it does touch - as per the cuts in the surface of the alternator.

Hmmm might have to try one of the expensive billet pulleys - just praying the woodruff key still holds tight considering the state of the alternator spindle.

 

[mattd1984]

Hi Mate

I have been having the same problems. I was at spa last year when it destroyed the crap repro top pulley. This year it did the same to another repro pulley. Keeps shredding the shims then working loose.

It would appear from mine that where the woodruff key has worn away part of its seating on the alternator shaft this will now just keep happening. It is meant to be a nice tight fit.

I am going to be replacing my Alternator in the next few weeks before a holiday to France.

We got back from EBI yesterday fine with it but starting to see shards of metal again where the back of the pulley is rubbing again. Was fine for probably 200 miles.

 

[Trikky2]

The pulley must be held tight by the nut pushing it onto its stop point on the shaft. If its even slightly loose then it will move, wear, start hitting the alternator as it wears, and destroy the woodruff key.

Woodruff keys are are an aid in extremis, they are not relied on to transmit forces or they will fail as they wear away due to movement/friction.

If you have a new alternator/dynamo and a new pulley and the pulley fouls then the manufacture is not as per original. Under such circumstances, to get out of trouble, one would have to use a good quality rings spacer similar to the one shown in the photos above with perhaps the addition of some locking compound to make sure it cannot move.

The pulley should be clear of the body of the alternator or dynamo, correctly lined up vertically with the bottom pulley and, above all, - tight. No movement is acceptable.

 

[StuF]

Cheers for the info fellas,

Have had an appraisal of the alternator and it looks like I will be installing a replacement as the damage is too much to be repaired economically.
Brilliant considering its only 12 months old. Unseen heat damage is a concern too - dont want an electrical fire!

Check out this article - it would appear our pattern parts are not all the same.

http://www.vw-resource.com/alternator_pulley.html" onclick="window.open(this.href);return false;

Might be worth checking your own pulleys/alternators just incase - there was no visible damage until I stripped it down.

 

[jonboylaw]

I had one collapse on me and nearly took the alternator with it.



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[Nugsy]

I fitted mine about 200 miles ago. Repro pulley as mine fell to bits, also bought a nice chrome Empi nut. Checked it tonight and the nut was loose meaning the pulley is loose to. a lot of black dust on the top pulley which I think may be the belt starting to wear :shock:

 

[Resto-raider]

I had the same issues. I tighten the nut to hard and it drove the pulley to farbaking making it touch the alternator. Looks as if the woodruff key is a bit too small for the repro pulley.
What I did is put a shim between the alternator and the pulley and I drove it like that 2200 miles to Spain and back without any further problems.

 

[BARKING MARK]

I replaced the original set up with a serpentine belt system from scat which included a new powdercoated pully. If you fit one of these make sure you sand off the powdercoat at the points of contact, if you don't the powdercoat eventually comes off of its own accord and then the pulley comes loose, apart from that a good fix.

 

[jonboylaw]

I replaced the original set up with a serpentine belt system from scat which included a new powdercoated pully. If you fit one of these make sure you sand off the powdercoat at the points of contact, if you don't the powdercoat eventually comes off of its own accord and then the pulley comes loose, apart from that a good fix.

I swapped to a BMD system, but used the nut and bolt pack from MST as it gives a better seating.
No problems so far.


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