740/940 Tightening Alternator Belt, with pictures

[SkyVolvo]

I had to tighten my alternator belt today, and while I've done much more significant work on my car before, I almost always had some handy guide with pictures. The only info I could find on this simple procedure was text only, so after I figured it out, I thought I'd post it for any beginners who might need it in the future. After finishing this, I noticed that the other accessory belts use the same mechanism, so the process should be about the same.

This is one of the simplest things a person can do, and it only takes a couple tools:

belt tightening 002.JPG (70.05 KiB) Viewed 12634 times

I used a 1/4" ratchet with a 10mm and 13mm sockets. A small extension was handy, and I also used a 12mm box end wrench.

First, loosen the pivot bolt just a few turns - I had to hold onto the nut on the other side with the 12mm wrench while loosening the 13mm bolt:

belt tightening 004.JPG (59.32 KiB) Viewed 12634 times

Then loosen the set screw a few turns with the same 13mm socket:

belt tightening 005.JPG (58.51 KiB) Viewed 12634 times

Then turn the adjusting bolt - clockwise tightens the belt, ccw loosens it. My understanding is that the belt should have about 1/4" to 1/2" give when you apply pressure to the middle of it - adjust until it reaches this point.

belt tightening 006.JPG (46.22 KiB) Viewed 12634 times

Once you've adjusted it properly, tighten the set screw. Then back the adjusting bolt off about a turn, so that the set screw is carrying the weight. Then re-tighten the pivot bolt, again holding onto the nut with the 12mm. Done - no more squealing belt.

[M820ABY]

Wish I'd found this site before I started. I loosened the pivot bolt but not the set screw so the adjusting bolt snapped.   Next time I'll look here before I start work. Does anyone know the thread and length of the adjusting bolt and where I can get a new one...?