Garage Door Sheaves/Pulleys
When you open your garage door, there are four pulleys that work to help wind and unwind the torsion springs. There are two pulleys in pulley forms near the springs and two pulleys on the horizontal track.
Due to the constant movement of the pulley, they can break easily. If you notice the garage door opening erratically, it opens half way or if you hear a grinding sound, then the pulleys could be the problem.
If you're replacing the torsion springs, then replace the pulleys as well. The pulleys are rated for 10,000 cycles just like the springs. If the springs are worn or broke, then the pulleys are probably near breaking as well.
The bearings within the pulleys tend to get stuck, so it can cause problems with the garage door. In fact, it can lead to additional wear and tear on the springs. Don't wait to replace the pulleys or the garage door springs.