I've just been investigating why the handbrake on my partner's car has suddenly gone slack. This is a common problem so this time I posted a video on YouTube to show how to diagnose it.
Slack handbrake on Hyundai i30 - YouTubeWhen I took the disc off the car, the lever wasn't sticking, but I found that the circlip that retains the pivot pin had popped off and the pin was halfway to falling out completely. I had a new lever so didn't attempt to refurbish the old one. Over 10 years and 219,000 miles, the slot in the pin that the circlip snaps into had almost disappeared. As mentioned in the video, if the handbrake becomes slack, find out what it is asap.