mazdatweaker_2
+1y
The spring is supposed to be secured at both ends as a tensioner to the wheel that moves. It sets up the correct tension prior to the bolt being tightened down to secure the wheel. Otherwise, like in your case, it's impossible to tell how much preload is on the belt.
There are two places that the spring attaches to. Maybe dirt covered one of them in your case. But I'd recommend you go back and do this proceedure correctly, so you know it's done correctly.