Snapped belt...

[PaulHere]

Oh no, it has happened again. My '83 2.0 has snapped another fan belt... I am crestfallen.

I last documented my fanbelt woes in my April 2016 Porsche Post 924 section I wrote: "the 924 has rubber bushes on the alternator, and secondly there are two sizes of fan belt listed for our cars – the sizes being 10 x 888mm and 10 x 900mm, why this should be so is unclear, maybe it is to compensate for extra electrical equipment on some cars"

But there must be something more, there MUST be more stress being put on the belt than normal. At the time I was only a couple of miles from home and had the rear demister on, but no headlights and there was no squealing or other warnings from the belt (10 x 888mm). I need my car to be more reliable. Any ideas people?

 

[vitesse]

Paul,
Fan belts can go at any time although you do normally get some warning & a visual check should show possible break up of a belt in use.
As to extra loads,the only loads are the alternator & water pump so if either is tight,then extra load is put on the drive belt,unless the belt itself has been overtightened,There should be freeplay on the slack side of the belt drive of approx 10-12 mm when depressing the belt towards the engine with a finger.
With belt off,as now just check that both these items rotate freely.Really. this is a fit & forget drivebelt,once correctly tensioned.

 

[scm924s]

888mm is the recommended size for the n/a without a/c, with is 900. Breakages generally occur if the pulleys are misaligned because of failed mounting bushes or a replacement alternator which has a pulley not in line with the others, it could also be a seized alternator or water pump.

 

[PaulHere]

Thanks, I was a bit upset with the turn of events, I wanted to drive!
But now I feel a little better, thanks to some common sense here and from a friend on the phone.

So now I'm going to get a new belt, bushes and sundry bits and pieces to refresh that area, will get the alternator checked out too to see if it's behaving itself.

Will keep you posted.

 

[vincematthews]

Also check the tensioning pulley which should rotate smoothly - it's cheap to replace if you're not sure, e.g., £20 for belt & pulley.
It's worth running your finger (carefully) over are the various pulley surfaces that the belt runs on to make sure there are no nicks or corrosion that might damage the belt. Make sure the tinware doesn't touch the belt and there are no oil leaks on to it.
Use a straight edge to check pulleys are in line with each other.

 

[geoff Ives]

About 15 years ago Mavis had a spate of belt breakages on her 924 2litre. When the first one went she called the RAC and they replaced it. A few weeks later it happened again and then again and after a major shouting match with the RAC it transpired that they had fitted to wrong belt first time and repeated the fault on the subsequent call outs.

I am now a member of the AA.

 

[PaulHere]

[style="background-color: #ffffff;"]Thanks Geoff, good to read you are still motoring.[/style]
[style="background-color: #ffffff;"]I'm going to get the belt and bushes and the alternator checked out - I don't want it to affect me again for a long time.[/style]