alternator clutch pulley

[davew]

my car suddenly started making a good awful rattling noise yesterday and when i got a look at it the aux belt is bouncing about ,i thought it was the belt tensioner that was knackered so i removed the belt and checked all the pulleys and they are all fine.
i believe the car has a clutch on the alternator pulley, i tried stopping the blades of the alternator and tuning the pulley but i can't get it to freewheel in either direction so am i right in thinking it needs replacing ?
if so i've seen various pulleys for sale and looks like you need removal tool as well to get it off ,anyone changed one and is it difficult to swap.

[steve_earwig]

I think cj's been there - oy vey, he just replaced the whole thing viewtopic.php?f=27&t=13143&p=199276&hil ... or#p199122 Looks like Grasmere's your man tho

[markw]

Or, you may have one that doesn't have a clutch!

[mjb]

our old hdi90 didn't cave a clutch on the alternator, pretty sure the v6 didn't either

[davew]

never thought about that how would i tell if it has a clutch ?
i can't think what else it would be, crank pulley is ok as are the other tensioner pulleys.

[GingerMagic]

Does it get quieter if you stick the air con on?

[davew]

no just the same with aircon on or off , if i give it a few revs it smooths out most of the rattling is at tickover.

[mjb]

when it happened to our hdi90, I think it ended up being the alternator just not being smooth enough in its rotation (worn bearings probably)

[Captain Jack]

Yeah I replaced the whole lot... But it was a seized clutch pulley on the alternator that was causing the belt flapple. I just bought a 2nd hand one for 20 quid with a good pulley and that fixed it.

[davew]

yes it's the clutch pulley got the alternator off last night and the pulley is seized solid, i'm going to see if i can change the pulley ,i can get an alternator for about £20 but my car has only done 90k so i'm keen to fix this one as long as it's not to expensive.

[gumby6371]

You could try googling for Ed China's alternator repair, remember watching it a couple of years back and I'm pretty sure it'll be floating around you tube.

[jasper5]

You need a special tool to remove the pulley, it's a large splined socket like the VW spline type.
Without going to my tool box I think it's 17mm...the splined tool has a nut fitting to hold the pulley whilst you undo the splined bolt.Provided you have the splined tool you can hold the pulley in a vice.

[jasper5]

http://www.amazon.co.uk/s/?ie=UTF8&keyw ... 3vgf1pwu_e

[davew]

didn't need the tool in the end as the guy at the motor factors fitted it for free, they had some for £28 but the only one that would fit was a genuine INA part for £46 ,i could have got a used alternator cheaper but as my car has only done 90k i would rather keep it rather than replace it with one than might have been to the moon and back.
just need to get it back on the car and hope it stops the aux belt flapping about.

[davew]

all sorted alternator back on and it's cured no more rattling from the aux belt