How do you change an alternator belt on 1994 Mazda 626?

Answer 1

You'll need an 18mm open-end wrench with either a long handle or a pipe to fit over the wrench end (for leverage). From the top looking down, you're going to get the wrench end on the bolt in the center of the idler pulley (located just behind the alternator and riding on top of the alternator belt.) It is a tight fit getting the tool between the radiator hose and the pulleys, but it is doable without removing any of the hoses.

Once you get the wrench on the bolt good, put the pipe over the wrench handle and turn/loosen the bolt by moving the wrench handle toward the back of the car (counter-clockwise). Just a few more partial turns and it should be loose.

Notice the long threaded rod sticking up behind the idler pulley bracket. Loosen that rod using a metric socket (don't recall the size). 4 or 5 complete turns should be enough. The idler pulley should now be loose enough to move up and down on its track, allowing you to remove the old belt, or put the new one on.

You should be able to put the new one on from underneath the car in front of the right front wheel. It should go around the alternator, then down to the air conditioner compressor then over the harmonic balancer, back up to the alternator. The idler pulley should sit on top of the belt from above.

Once you've gotten the new belt on, tighten the threaded rod. This rod merely holds the back of the idler pulley bolt in place so you can tighten the bolt from the front of the pulley. The rod just needs to be tight enough (firm) to hold the nut/bracket in place.

Have a friend push down on the idler pulley to tension the belt to the desired level while you tighten the 18mm bolt on the front. Once that is tightened, check that the threaded rod is still firm against the little bracket at the bottom the rod. This helps keep the idler in place and tension on the belt.

That should do it!