Take a very thin piece of wire, like a straightened paper clip, and run it between the spring and edge of the plastic. There is a small space there. If you push on the spring you'll see where I'm talking. I have the X pedals and have gotten small stones and mud in that space. The dirt keeps the spring mechanism from working properly. It's not a big deal to take the cleats off and clean them. If you do be careful not to tighten the screws too tight as you won't be able to clip in.