Worn Pulley Shaft-squeaking Alterntor Belt.

[mrben]

Hello there. (galaxy tdi 1.9 v-reg) I'm after the name of the shaft that runs behind the alternator (it may be part of the alternator bracket? but i'm not sure, its hard to tell). If you were looking down on it, the shaft has a tension-er on the right hand side (which is on the right hand side of the alternator), and the left hand side has a pulley bolted to the shaft (which is on the left hand side of the alternator-but underneath). This shaft has worn, making the belt squeak all time. My garage has informed me that this was a common problem with these vehicles, would anyone here know if thats the case? (i hope i'v sort of made it clear on what i'm after). Regards-Ben.

[zorgman]

alt pulley tensioner shaft, ive never had one go rather the bolt comes slack at end so put a larger dia washer on and new m6 bolt

[mrben]

hello. yes i was wrong, it was the actuall caseing the shaft was in that was worn!! bugger of a job...

[seatkid]

Usually caused by a seized one way clutch on the alernator pulley. Check the alternator pulley works correctly if you want your tensioner to last more than a few weeks.

[mrben]

Thanks for info. I do have a ongoing aux.belt sqreech when under load which i can't seem to get rid off (new belt and tensioner, and there is knocks from the front suspension area/s??? strange...) so it could be the alternater pulley? how would i test that, it seems to turn fine when the engine is running :unsure:

[seatkid]

Take off the aux belt. Then use a screwdriver or similar and carefuly hold the alternator rotor still. You should be able to spin the pulley in the non-driven direction, whereas it should be locked in the driven direction.

 

Common fault is the one-way pulley seizes (locks in both directions), this in turns transmits repetitive shocks to the belt, tensioner (which jumps about like crazy) and other auxillaries. Consequences are noisy belt and failed tensioners.

[mrben]

Many thanks seat kid, i'l try that and let you know

[mrben]

i havn't checked yet, but just an observation...wouldn't the battery light come on if it was seized, as the alternator wouldn't be spinning, thus not giving out any charge?...

Thanks.

[SilverBeast]

Hi mrben,

 

The alternator has a clutch on it so that the pulley can only drive the alternator in one drection. If the pulley tries to drive the alternator in the "wrong" direction the pulley will spin but not turn the alternator. If the clutch fails, then the pulley will drive the alternator in both directions which is a bad thing. The PD TDI diesel engines don't rotate at a constant speed (at least at low speeds) so alternator would be constantly trying to speed up and slow down which varies the tension in the drive belt and cause noise, tensioner jumping an wear as seatkid describes.

 

The alternator will still be charging (which is why the alternator light won't stay on as this only indicates when it isn.t charging) .

 

Hope this makes sense. I have gleaned this information from reading this and other sites over the last year or two. I would suggest that you continue reading all the new technical threads as they are posted, if you have the time, and you will soon see repeat "common" problems and solutions. I haven't experienced this myself (yet! - I just know this is tempting fate) but hopefully will recognise it if it does occur.

 

By doing this I have been able to diagnose and fix wipers, run-on pump brushes and leaking rear wash hose quickly and without having to resort to an (expensive) garage repair.

 

Good luck

[mrben]

hello, yes thanks, makes sense. hopefully check it tommorrow, thanks

[Sher]

Seatkid was spot on.

 

Seems this alternator clutch seizing is across the VAG group range. When I went to a Spanish mechanic in a small Spanish village/town at 102,000 miles with my 1.9TDi 115bhp Ghia he diagnosed the problem at once and showed me the special tool required to change this one way clutch.

Total cost €100 and the "Alternator Workshop" message never came on again, even after 30,000 miles.

 

Cheaper than a new alternator.

[mrben]

Hello beast. Took belt off, and no pulley doesn't spin easy in other direction (actually not at all), but my galaxy is the earlier model, not the pd engine (99 v reg td), so friend at garage said pulley might not be clutch type pulley? Whatdya think? (i have picture of alterntor i can send if you like) Ta

[seatkid]

AFAIK 110bhp AFN engine has a one way alternator clutch, but the 90bhp AHU does not. Take the part no. of the alternator (printed on the plastic end housing) and a bit of googling will establish what is what. Edited August 15, 2012 by seatkid

[mrben]

ok thanks seat.

[alan_131]

Just a thought but I've seen replacement alternators advertised without the clutched pulley - with a note from the supplier that this has been deleted as it only needs a plain (non-clutched) pulley as this does not affect the alternator. (Which, of course, it doesn't - just trashes other stuff). So, just because you have an alternator at the moment which does not have a clutch, doesn't mean you shouldn't have one...

[mrben]

Hello chaps. Done the pulley, and that sorted it, excellent, well chuffed, thanks very much for your advice. Tensioner doesn't jump at all now, and no squeaks!