Crank / Alternator belt pulley...

[JeffTheGeek]

Hi guys.



I've had a catastrophic failure of the alternator belt pulley that is on the end of the crank. Its totally destroyed itself in the centre (fixing) part.

Not too much of an issue for me to replace it (with a newer, differently designed unit), along with a new damper (which is different due to the different updated pulley), but the manual makes reference to marking the old part so that it is refitted in the same position. Obviously I cant do this (as the old part fell off into the undertray, and I'm fitting a new part).

Is the positioning of the pulley critical (I'm guessing that it is), and if so, how do I know which of the eight possible positions does it need to go in?

Has anyone else had this happen? The manual mentions about a spacer that should be fitted (even if one wasnt before) - is this an indication that Audi have had problems with this in the past?

Thanks for any help or advice.

Jeff.

[JeffTheGeek]

sorry,

I should have said this on a 05/06 2.7tdi Quattro S Line Avant

[Peter D]

It is not a position issue but one or direction of rotation, once they have been run in one direction it is unwise to reverse them. Check to see if you have a one way spragg clutch on the alternator pulley and it is functioning.
What exactly do you mean by this"destroyed itself in the centre (fixing) part." ?? Are you suggesting the Centre pulley vibration damper has failed. Please provide and engine code.
Regards Peter

[JeffTheGeek]

Hi,

The manual states:

Removing and installing vibration damper Removing– Remove poly V-belt → Chapter.– Mark position of vibration damper for re-installation.– Remove bolts -1-.– Remove vibration damper.
It is indeed the centre pulley vibration damper that has failed. Bascially there is now one big hole in the middle where there should be 8 small ones. It has either failed, or i suspect that what has actually happened is 2 of the bolts have vibrated themselves out, 3 have been sheered off (and are still in the end of the crank and will need to be drilled out), and 3 where left intact in the end of the crank (and I have simply unscrewed those). I'll upload a picture later when I get home, and post the engine code. The replacement part is 059 105 251 AD, and has required the tensioner / idler to be replaced as well (along with a longer belt, but I would have fitted a new one anyway).

Jeff.

[Peter D]

Yes if removing an existing pulley then you mark it up so when refitting the pulley and the crank have the same positional relationship. A new one is not an issue, however you will need new bolts. 20nm plus 90 degrees. Regards Peter

[JeffTheGeek]

Ah, I see.

New bolts already purchased (along with the shim and everything else!).

Thanks for the help

[Peter D]

Do you have a spragg clutch alternator pulley or not. You appear to have the manual so you can ID the pulley by the method of removal. Regards Peter

[JeffTheGeek]

I have no idea what a spragg clutch pulley is, but I do know that none of the pulleys are siezed in any way and they all turn easily by hand.

The box is an auto tiptronic.

[Peter D]

A spragg clutch is a one way clutch inside the pulley. Check in your manual the end fittings are different. A seized clutch can shread an aux belt at idle. Regards Peter

[JeffTheGeek]

I'll check it out, but I suspect it will ok as I'd imagine the belt would shred way before the main pulley did (the belt was still in one piece when i retrieved it from the undertray).

Jeff.