Last Friday the alternator in my 83 GSL decided to seize on me. I was kind of fucked distance wise so I just cut the belt and drove it home with all the electrical accessories off.

Now I bought a reman alternator with a lifetime warranty. That went in no problem. But how the hell do you get the belt on? It's behind the two others, I assume the A/C compressor is used as the tensioner for the first one, but what about the second one?

 

I assume by the 2nd one your talking about the air pump belt. In which case the air pump adjusts to provide tension for the belt.

 

you must remove the smog pump and a/c belts. its kinda tricky but the alternator belt can be wiggled over the fan so its not necessary to remove it.

 

I managed to get it through the fan...then I went to loosen the aiir pump. And the bottom bolt snapped right off.

This is on a virtually rust-free 83 with 55k miles.

God ******* dammit....

 

its okay, dont get mad. its an older car so ***** gonna break like that. the tensioner bracket for the smog pump is easy to remove. i think its just one bolt on the front cover just above the omp. take the braket off and drill the rest of the bolt out of it. after its out re-thread the hole and its as good as new. may take 30-45 mins.

alternative: remove the air pump and all emissions if smog tests are not required where you live.
theres a really great write up for removing teh emissions that you can find in the faq's

 

or see if there is any of the bolt sticking out of the other side of the bracket and remove it with pliers or channel locks.

 

I had to replace my belt not to long ago. I found it helped me alot if you removed the fan and radiator shroud.

Then loosen the bolts at the base of both the airpump and the A/C compressor, don't have to take them out. These are the ones the accessories pivots on. Then loosen the bolts that slide along the bracket, the adjustable ones. Rotate the accessories inwards this allows the belts to go off and on easier. Repeat this for the alternator if you have it mounted solidly already. Take all the belts in front of it off. And then have fun wiggling the belts back and onto their respective groves, this was the biggest pain. Then have a friend hold the accessories tight, away from the engine while you retighten all of the bolts so you have nice tight belts.

Good luck, here are some photos of when I had to do mine.
With all of the belts off and the accessories rotated inwards.

What happened to the old belt? It shredded itself, from age.

New belt.

All the new belts back on and ready to go.

 

Now what I'm wondering is - how do I get the A/C unit to move? The screws on top look like they're for adjusting but the bastard doesn't move an inch when I tighten or loosen them.

Your A/C setup looks way different than mine. I wish mine had a simple slide bracket like that

 

Loosen the bottom bolts/nuts on the AC comp.

 

I'm using this phot because you can see the bolts easier.