Your truck's parking brake, also called an emergency brake, is more than a convenience when parking on an incline; it can be a lifesaver should your hydraulic brake system fail during driving. A loose parking brake should be adjusted as soon as possible if it fails to engage properly. Fortunately, making this adjustment is a fairly simple repair for most car owners who know how to use basic hand tools. Below is a list of what you will need as well as information on how to perform a parking brake adjustment:

Tools and materials needed

  • Floor jack
  • Jack stands
  • Flat blade screwdriver
  • Electric lantern
  • Shop towel
  • Wheel chocks

Step-by-step procedure

1. Work with your personal safety as a priority - Performing a parking brake adjustment isn't difficult work, but it can dangerous if you fail to take the proper safety precautions. Never get underneath a jacked truck without it being supported by sturdy jack stands rated for the weight of your vehicle; a floor jack alone could fail, and you may be crushed as a result. In addition, don't substitute jack stands with cinder blocks or other similar materials that could suddenly disintegrate under a load.

2. Jack the vehicle's rear end - Place your truck on a hard, level surface where you can safely access the wheels, and insert wheel chocks in front of the front wheels; this will prevent the truck from rolling forward as you jack the rear end. In addition, be sure to place the transmission into its park setting if it is an automatic transmission, or shift a manual transmission into first gear to further immobilize the truck.

After the chocks are in place and the transmission is "locked," position a floor jack beneath the rear differential and elevate the truck until the rear wheels are approximately an inch or two above the ground. Next, insert jack stands beneath the wheel axle tube on each side of the differential to stabilize and hold the vehicle.

3. Locate and remove the rubber access caps - Once your truck is safely jacked and secured, carefully maneuver yourself beneath the rear end and locate the rear wheel brake assembly on each wheel. You will need to position a lantern or other light to illuminate the brake assemblies. Next, look toward the bottom of the brake housing of each wheel, and you will see a small rubber cap that protects the internal components from water and debris intrusion. Slip the tip of a flat blade screwdriver beneath the lips of the rubber caps and gently pry upward to loosen them. Be sure not to lose the caps if they suddenly "pop" out of their mounts.

4. Rotate the star wheel adjusters - The tension of the parking brake is maintained by devices that push the brake shoes apart or pull them closer together, depending upon the desired settings. These devices, known as star wheel adjusters, will tighten your parking brake tension when rotated with the tip of a flat-blade screwdriver. For the star wheel adjuster on the driver's side rear wheel, turn it upward to increase tension, and turn the passenger side star wheel downward for the same effect.

When first adjusting the star wheel adjusters, turn them no more than one or two turns, then pause to test the wheel tension. To test the tension, set the parking brake on your truck, then attempt to turn the rear wheels by hand. If they cannot be turned at all, then you may have made the tension too tight; However, if you can turn the wheels without much effort, they are still too loose and you will need to continue to adjust the star wheels in slight increments until the balance between looseness and tightness is ideal.

5. Replace the caps - Once you have adjusted the star wheel adjusters and are satisfied with the degree of tension in your rear wheels when the parking brake is activated, you can replace the rubber caps to continue protecting the star wheel adjusters and other components.

6. Test your parking brakes - After making the adjustments and getting the truck off the jack, be sure to take the truck for a test drive and use the parking brake on an incline to ensure it will hold.

If you feel you cannot do this on your own, contact a truck service shop, such as Godfrey Brake Service & Supply.