Lift up the leather cover over the e-brake handle (it's held down by velcro) and you should see two sets of two nuts, one on each side of the handle. These are attached to one end of cables, one going to each rear wheel. With the emergency brake off, loosen the top nut on each side. It's there to lock the other nut in place. Next, tighten each of the lower nuts a couple of turns. Pull up on the emergency brake and see if it feels better. Be careful not to tighten the lower nut so much that the brake is engaged all of the time. Once you have it where it feels right, tighten the upper nuts while holding the lower ones in place. This will prevent them loosening by themselves.
It's normal for the emergency brake to loosen over time as the rear brakes wear and the cables stretch a little. Hope this helps.
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