E-brake keeps loosening up
 

I like to have my e-brake so that as soon as it engages it’s pretty tight. However when I adjust it with the adjuster screw, it’ll tighten up and then a week later it’s back to its default position. And by that I mean you have to have the fucker 90 degrees before it keeps the car from moving. I don’t know why it keeps loosening up but maybe the cable is stretching. I don’t feel like I’m doing anything wrong. Just use a 10mm to adjust the screw right?