How to Adjust Brakes on a Car

You can only adjust drum brakes on a car. Disc brakes have no adjustment. With that in mind, rear drum brakes only take on 20 percent of the braking responsibility of vehicles and if they become unadjusted (through normal wear and tear and neglect), the front disc brakes will need to over-compensate and cause premature wear and other problems for the front brakes. Since there are so many types of vehicles, there are also different ways to adjust the rear brakes on a car.

Instructions

How to Adjust Brakes on a Car

1

Determine the amount of drag on the rear wheels caused by the adjustment of the rear brakes. This would be determined with the vehicle elevated and by spinning the rear tire. If more than a turn or two occurs before the wheel stops on its own, the rear brakes are out of adjustment.

2

Determine what type of rear brake adjustment is available for the vehicle. While many domestic vehicles offer small portholes on the back side of the backing plate to adjust rear brakes, many import vehicles have self-adjusting rear braking systems that can be adjusted when pumping on the foot pedal and/or tightening of the parking brake mechanism.

3

Adjust the rear brakes of a domestic vehicle by removing the rubber plug from the backing plate porthole. In some cases, prior to brake shoe replacement for the vehicle, the porthole may appear as a stamped part of the backing plate that needs to be punched out with a hammer and chisel and then a rubber plug should be added to prevent moisture and dirt getting into the rear braking system. Some of the backing plates may offer two different options of the punch-out plugs (due to the fact they're manufactured for each side of the vehicle) so choose the plug that would align to the star wheel of the adjusting lever. (This would require removing the drum to determine.) Once the plug is accessible, depress the star adjuster retainer pin with a screwdriver and adjust the star wheel to extend the shoes outward to contact the drum. Turn the star wheel a couple of times using the brake adjusting spoon and turn the wheel until you notice drag on the tire that does not allow the tire to make more than one revolution before stopping.

4

Adjust the parking brake mechanism of a foreign car to adjust the rear drum brakes on that. You may have to determine whether there's a lever in the drum braking system that needs to be repositioned or if you can adjust the rear brakes by applying and releasing the parking brake mechanism repeatedly. This might also require tightening the parking brake handle inside the car. You could locate the nut down inside the parking brake mechanism and tighten it with a ratchet, socket and an extension. You may not get the drag out of the rear drum brakes on an import vehicle that you can manipulate on a domestic vehicle due to the fact that many are self-adjusting, so there's only so much you can do.

5

Check the brake adjustment of the vehicle regularly after you've discovered how to and try to get into the habit of using your parking brake each time you park. The parking brake mechanism in many rear braking systems is integrated with a self-adjuster lever or cable (even on some domestic cars) and you can get more longevity out of the adjustment of rear brakes.