It sounds like you're describing a ratchet mechanism and that spring is supposed to push the teeth of the pawl into the teeth on the plate, and that holds the brake lever engaged. Then you press a button to push the spring-loaded pawl away from the teeth on the "rack" to allow the lever to be lowered.
It also sounds like the spring has its hook broken off the end that went into the hole on the pawl. The wire the spring is made of is usually rather hard and brittle. You might consider stretching out the coiled up part, (if there is one), to make it longer so you can form a new hook on the end. Because that wire is brittle and might snap when you bend it, consider warming it up first with a very small flame on a propane torch. If it turns orange and is about to melt, let it cool first before you put pressure on it to bend the new hook.
The alternative is to find a spring in a salvage yard or make one from something else.
Another possible reason for having a hole in a pawl is to be able to stick a cotter pin in it to prevent it from engaging at all. That is often a part of the cable adjustment procedure.
If it sounds like I'm off base, can you post a photo?
Wednesday, February 22nd, 2012 AT 12:01 AM