The most probable cause of handbrake malfunction is corrosion. Brake fluid is hygroscopic which means that it absorbs water. Most brake parts are submerged in this brake fluid. You may find, over time, that the water content in the brake fluid is sufficient enough for rust to take place. With rust now in place, finer parts such as screw threads start to deteriorate. The brake pad will wear away and move further away from the brake disk. This will result in more movement being required from the handbrake lever to take up the slack. If such a situation exists, tightening the brake cable will only serve to lower the brake lever and ‘not’ move the brake pad closer to the brake disk or take up any slack between the piston and the brake pad. Sometimes the best way around handbrake malfunction is to purchase and install a completely new set of brake calipers.
Before working on the handbrake itself, you will first need to ensure that the brake shoes are fully positioned in the brake drum. This can be achieved quite simply by first turning on the engine, pressing the brake pedal a few times and then turning the engine off. You can then jack the rear of your car up until the rear tires are off the ground. Ensure that the vehicle is supported on jack stands and the front tires are secured as you don’t want a situation where the car rolls forward while you’re working. Pull the handbrake lever up until you hear approximately three clicks. If you have a pedal type handbrake, press it down until you hear the three clicks.
Step 1: There is usually a console trim that covers the parking brake lever. Refer to your car’s specific owner manual for instructions on how to remove this covering. You will then notice a locking pin in place that will need to be removed.
Step 2: You should be able to locate one or more adjusting nuts or a turnbuckle at the base of the hand lever. You will need to tighten these adjusting nuts using a ratchet and deep socket in order to get rid of any excess slack in the brake cable.
Step 3: Next you will have to check for a slight drag of the brake shoes against the brake drum. This can be achieved by manually rotating both rear tires with your hands. If no drag is evident, you will have to tighten the adjusting nut until a slight drag can be felt. Be cautious not to over tighten as you wouldn’t want a situation where the cable snaps as a result of over tension.
Step 4: Once you’re confident of the "slight drag" you were hoping to achieve, you may then fit a new adjuster locking pin and reinstall the console trim over the handbrake lever.
Check: Apply the parking brakes and release the parking brake lever. As a check before lowering your vehicle, notice how far down the parking brake lever travels before the parking brake is effectively engaged. If you are not satisfied, you may have to re-adjust the parking brake (refer to step 3 above). You can then lower your vehicle. Finally, test your handbrake level on a hill. Ideally, your parking brake lever should not have to be pulled up too high to effectively hold your vehicle in place.
References: www.bmwe36blog.com, www.206info.co.uk,