Any trick to changing all 3 belts?

Thanks

 

Not that I recall. It was a straight forward procedure. I'm down to a double belt setup myself - just the water pump and a relocated alt now.

 

What size is that middle belt that goes to the air pusher?

Had the inner belt break on me yesterday. Got the other two at Advance. but they did not have one to fit the middle belt.

 

According to your profile, you have an '85. It doesn't say which model, so you either have a 12A or a 13B engine. Try this link:
http://www.rockauto.com/catalog/x,ca...,parttype,8900

Adjust the search listing if you need to for a different engine set-up.

I haven't run an air pump for a while, so I can't help you more than that as far as belt size.

I have a modified set-up and my local parts store let me take a few belts to try them out before buying.