Ok, so last night my Alternator belt shredded itself and took the air pump belt with it. This is my fault, I never got around to changing the belts when I first got the car(was sitting around for 8 years.) A friend too me home to my 87 S4 and got the Alternator, Air Pump, and Power Steering belts off of it to put on my 91 S5(Vert if that means anything).

Well, Alternator belt went on just fine. The Air Pump was a different story. What was easy on the S4 was not on the S5. It's like the pump is placed differently. Along with the Power Steering Belt. Seemed different. So I put the old Power Steering on. Drove home just fine. My question is, was there a change between these 2 models with belt sizes? Is the Air Pump mounted further away from the pully's? I'm seriously confused because it took all I had to try(<-keyword) to put it on without any success.

And don't worry, I have already bought the correct belts to put on my car, I just needed a way to get home last night. And no I'm not driving it now.

 

I am assuming we are talking about belt widths and not lengths when you say sizes???

width wise, most autoparts stores will reference both 15 and 17 mm fitting our pulleys. So you could have different widths if belts were bought at different times,

Or do you mean lengths?

The air/water pump belt is longer on the S5 models as the pulley is different on the air pump. Also the pulley is different size on the car with engine speed power steering vs vehicle speed power steering but you should be able to adjust the idle pulley down enough to make up for it.

 

Makes sense. Thank you very much for that information.