Why is my poly belt hopping ?

[Danny DeVito]

638 Vito. I've changed the tensioner but the belt is still hopping about. Could it be stretched or some other reason ?

 

[panason1c]

Usually caused by the 'free-wheel' pulley, which is fitted to the alternator, seizing up.........a new pulley costs about £80

 

[Mercedes-2010]

Usually caused by the 'free-wheel' pulley, which is fitted to the alternator, seizing up.........a new pulley costs about £80

As above, but it can be done in situ and needs a special tool, any alternator / starter reconditioner will do it on their forecourt in a few minutes...

 

[stevieraylamb]

Alternator pulley a commom problem on vitos with valeo alternator, theres a german replacement which is a lot better!

 

[Danny DeVito]

I had the alternator bearings and brushes replaced a month ago, it got noisy. He said the pulley seemed ok and not much point in replacing it at 90+€ I guess he was wrong then. I think its a Bosch. Must be that though. All other pulleys seems tight. Is it that the pulley jams a little and goes again ?

 

[stevieraylamb]

If you listen to the left of the merc star at the bottom you can sometimes hear it rattle (with the bonnet down)

 

[Danny DeVito]

I can hear a little squeak like a belt rubbing sideways. So i may remove the new tensioner an try return it to exchange for a pulley then.

 

[stevieraylamb]

Thats sounds about right dan,when you rev the engine sqeauk sould go away.

 

[peapod]

dealer said nothing was wrong with mine when it hopped. I eventually replaced the generator pulley free wheel and it was sorted. I saw a thread which said failure of the freewheel can damage the generator. I think the bounce was worse when cold so yes the freewheel freed up a bit when hot.

 

[carat 3.6]

If the crank pulley has a rubber damper built in, check that too.

 

[Danny DeVito]

I had the gene overhauled because the bearing became noisy. He mentioned the pulley but said it was ok and because of budget he said not really any need to replace it. The noise and hop started the same day. Now i wonder if the pulley was seizing a bit and the yanking caused the bearings to go. Now i wasted my money on the tensioner which is still in the car and have to wait a while to get a pulley. Any chance of getting oil into it ? (not hoping for much there) No crank damper either. The gene is quite tricky to get out too. I had to drop the engine a fair bit and undo the drive shaft to get it out.

 

[panason1c]

Any chance of getting oil into it ? (not hoping for much there) No crank damper either. The gene is quite tricky to get out too. I had to drop the engine a fair bit and undo the drive shaft to get it out.

The one-way 'sprag' clutch, which is built into the pulley, is a sealed unit and not servicable in any way.

I replaced my pulley with the alternator in situ (ml 270cdi), there may be enough room for you to do the same?

 

[jay1983]

The one-way 'sprag' clutch, which is built into the pulley, is a sealed unit and not servicable in any way.

I replaced my pulley with the alternator in situ (ml 270cdi), there may be enough room for you to do the same?

I have been lookin on ECP for the pulley which sits at the top left of the engine (not the tensioner).
Does any1 no where I can get this from and for how much?