I recently replaced the drive belt on my '03 Vibe GT. I was under the car placing the belt and my brother in law was cranking down the tensioner. Like many others the poorly designed tension release nut sheared off. Plan B was a c-clamp method I read about on a GenVibe thread. Neither four or six inch clamps would do the job. An hour later I found the winning solution.
I assume most auto parts shops will rent out a "serpentine belt tensioner kit". I rented one from Autozone for 30 bucks. In this kit you get two thin steel bars that you can change the angle to get the leverage you want. All I needed was the bars as I was able to place one end under the tensioner caliper and pivot on the same bolt that the tensioner itself pivots on. With this set up it was crumb cake to release the tension and replace the belt.
Also, before you remove the old belt, slow down and draw up a quick diagram or take a picture of where the belt runs. It will save you an image search.
I cannot be happier to not have to buy a new tensioner assembly!
