Alt belt failures

My daughters 2002 m13 engine has thrown its second alternator belt in 6 months or so. I inspected the lower pulley and alternator for faults after the first time and non are apparent. I had to go and rescue her from Derby as her brake down provider(AA) did not consider her urgent and they would only tow her to the nearest garage as they would not attempt to fix that roadside! That garage closed at 6 so the time they would have got it there would have been too late. What do they do at the roadside know then one must wonder!
I also did a "search" using "pulley failure" and "Alt belt failure" but got no hits so that section of the forum is not much use which is why I have started this thread.
Do both the single cam and dual cam engines use the same belts at the front i.e. Alternator and steering pump?

I can't say why it's throwing belts without having a look but are you sure they've not been over tightened?

Do the pullies run staight and true?

Kirkynut

M13a and g13b use different length belts.

It could be a bad bearing only showing when it warms up? Any signs of rubber deposits on anything?

When you check online and fill in the details of the car they knock out the same belt for the 2001 with the dual cam and 2002 soft top with the single cam. I got the last ones from General Traffic and it also came up with the same belt, make of Gates and the number was 4PK850. It went on well enough and the adjustment seems correct being in the middle of the range. There was quite a bit of rubber deposited on all three of the pulleys which I cleaned off before putting the new belt on. As I say I fitted it about 6months or so ago and there has been no squealing or screeching and I checked the tension about three weeks ago and it seemed OK. What make of belt do you recommend as being considered the best?
When you say bad bearing which one would that be? The pulley is rigid apart from the flex bit which looks sound, the water pump has no movement or leaks and the alternator did not show any wear either!

If I remember correctly, Gates belts are quite highly regarded

I wouldn't hesitate to fit a gates on the Jim. Had a Gates on my last car and that was a Porker.

That's what I thought but these Chinese are so "clever" they can copy owt! Anyway the car is up and running with a new Gates belt so time will tell!