The ebrake cable seldom needs adjustment. Usually the drum brakes are worn and the star adjuster isn't tightening them properly. Technically, there's an access plug on the backing plate for the drums that's supposed to allow you to turn the star adjusters with the wheels still on the car. I've never had any luck with those. I take off the wheel, break the drum loose, and make my adjustment. I consider it a good opportunity to inspect the brakes and repair/replace as necessary. FWIW, I like to put a little anti-seize compound where the drum meets the hub to make it easier to remove next time. -scott