Aux belt keeps coming loose

[Graham81]

Hi there, my aux belt keeps coming loose every 100 or so miles. It was a new belt as the one that was on the van originally was doing the same.
Ive done all the bolts up as tight as i dare and yet it will still come loose after a short period of time.
The alternator is still tight as hell and none of the bolts are loose yet the belt is slack as,
Is there a pre tensioner available or a way of locking the alternator in position?
Cheers
1.9dg

[pauly8888]

Do you think this problem will be solved if the belt was smaller? Would you be able to adjust the fitting if the belt wasn't so big?The original belt may have not been the correct one. Take the belt to the Motor Parts shop and ask for one a centimetre or so shorter.

[Graham81]

cheers for the reply, the belt should have been the right one I got it from unipart. It tightens up fine its just a mystery to me that it comes loose so frequently, its probably knackered now as i had it smoking yesterday!
I was just wondering if mine had a part missing or if there was a locking assembly available.
I will have to tighten it again, just dont want to break any bolts by over tightening them.

[hulky]

cheers for the reply, the belt should have been the right one I got it from unipart. It tightens up fine its just a mystery to me that it comes loose so frequently, its probably knackered now as i had it smoking yesterday!
I was just wondering if mine had a part missing or if there was a locking assembly available.
I will have to tighten it again, just dont want to break any bolts by over tightening them.

As Pauly has said check the belt is the right size

[NicBeeee]

HI

How much give was in the belt after you had tightened the adjustment bolts. If it was too tight then the belt may have heated up by slipping on the pulleys and in turn stretching itself

[pauly8888]

The belt on my van was the opposite. It was too tight and the alternator adjustment was on its lowest setting. I took it to the shop and just got a bigger one.

[California Dreamin]

Is this a case of the pulley halves coming apart? usually held together with 3 X 8mm bolts.....

Martin

[Graham81]

Thanks for the replys
I normally fit it so that i can turn it half way round or 15mm down on a push, I suppose it could be stretching will have a look at it tommorrow.
I hope its not the pulley, is that the crank one? Is that in two peices?
It must have been a problem for the previous owner as there is a couple of belts under the bed, one is a blue plasic band that looks like some kind of emergency setup and a belt that is too short!
There is loads of adjustment on the alternator so its not too short.
Cheers chaps.

[Hacksawbob]

Long shot.... Check that the you have the correct Alternator pulley so that it lines up with the crank pulley if. Also there is a bracket that holds the Alt. One side of this can be snapped but hard to see without taking it off. It may look fine until its under load then it twists and its goodnight Vienna.

[Aidan]

two different sizes used depending on alternator, 1050 and 1100, a stretched 1100 will be loose on a 45 amp alternator very quickly