Aux belt jumping

[RichValver]

Basically my aux belt has jumped a grove on the crank pulley. Moved over one to the cambelt side. Any idea what would likely cause this. Has happened twice now (on diff aux belts) but same tensioner

Any ideas welcome

?

 

[JamesBryan]

Twice and it hasn't taken the cambelt out!

You lucky, lucky b*****d.

 

[RichValver]

It's only moved one groove on the pulley ?

 

[JamesBryan]

Dodgey tensioner?

 

[Brigsy]

Replace the tensioner and belt before it ends up in tears. Also check the crank pulley and any other pulleys that run on that belt are not failing.

 

[RichValver]

It will be replaced. I'm just wondering what the likely caused would be for it jumping towards the engine.

 

[RichValver]

No idea if this has been causing my issue but seems likely it was something to do with the tensioner. No idea what its been rubbing on as I cant see anything in the way. 20k/3 year old tensioner. But has had a couple of replaced belts as have had to replace Pas pump and a/c pump in the past

 

[RichValver]

Also, does anyone know how tight the bolt should be in this pic(between spring/bracket)? Should I tighten it up or leave relatively loose as it comes?

 

[RichValver]

Turns out the cause of my belt jumping is the gap between the pulley mounting and the pump itself. I purchased a recon pump from ACS off eBay but the shaft has been pressed further in than the original so is roughly 1 rib closer to the engine hence causing my belt to jump. With checking if you have purchased a recon pump.

It's only a couple of mm which is why I hadn't noticed. Above is the original gap