How to Adjust Rear Brake Pads

This is what rear drum brake pads look like once the drum has been removed.

Keeping the rear brake pads (or shoes) adjusted is an important measure in ensuring a braking system is in sync. Since the rear brakes only accommodate 25 percent of the braking capacity, if they become unadjusted, the percentage drops and the front brakes take the brunt of the braking load. This causes premature wear and tear on the front brake pads and rotors. Applying the parking brake (whether an automatic or standard transmission) every time the vehicle is parked will assist the longevity of keeping the rear brakes adjusted on most all vehicles.

Things You'll Need

• Wheel block
• Tire iron
• Jack
• Jack stands
• Safety glasses
• Penetrating oil (optional)
• Hammer (optional)
• Ratcheting wrench set
• Pliers
• Screwdriver
• Brake adjusting spoon

Instructions

1. Place wheel blocks in front of both front tires with the vehicle parked on a level ground suitable for lifting.

2. Ensure the parking brake of the vehicle is not engaged and then break the rear lug nuts loose with the tire iron; 1/4 counterclockwise before lifting the rear-end of the vehicle with a jack.

3. Use the jack to lift one rear quarter-panel at a time and then set the vehicle safely and securely down onto the jack stands. Be sure to set them away from the rear backing plates of the vehicle if you're using a rear axle to set onto the jacks (this would be for rear-wheel, four-wheel or all-wheel drive vehicles).

4. Repeat Step 3 for the other side so the rear-end of the vehicle is elevated and then finish removing the lug nuts and wheels.

5. Spin each drum by hand to inspect the adjustment of the rear brakes. Rear brakes that are properly adjusted will have a slight drag on them and the drum should spin no more than a half a turn. Over one full turn indicates the brakes are unadjusted.

6. Put on safety glasses and locate the parking brake along the under-rail of the vehicle. Most run down the left or driver's side, but some imports can run down the center of the undercarriage. Check for looseness or dangling in the cable. If necessary, locate the cable adjustment mechanism and tighten the adjustment nut with a ratcheting wrench while holding the mechanism with a set of pliers. Not all vehicles will have this option. Tighten the adjusting nut until the cable no longer dangles.

7. Check the rear backing plate for small rubber plugs. If present, these plugs prevent elements from entering the rear brakes and are strategically located near the adjusting wheel mechanism for the rear brakes. If there is a porthole but no rubber plug, the odds are good that the adjusting wheel may be rusted or seized or both. If the star wheel is seized or there are no rubber plugs, skip to Step 10.

8. Use a screwdriver to feel around inside the porthole. Locate the wheel adjusted rest and press it slightly away from the star wheel. Insert the brake adjusting spoon while maintaining the rest away from the star wheel. Turn the star wheel up or down with the spoon. Depending on which side of the vehicle you're working on, it may be up or down to expand the shoes outward (this is what the turning of the star wheel does). Try a couple of turns of the wheel and spin the drum again. If it starts to resist, you're going the right way. If it spins more easily, adjust the star wheel in the opposite direction.

9. Tug on the parking brake cable near the side you're working on to re-center the shoes and check the drag on the brakes by spinning the drum.

10. Spray a copious amount of penetrating oil on the center hub hole of each drum. Allow the oil to soak in a few moments and then remove the drum. If the brakes are under-adjusted, the drum should come off freely. If the drum is rusted stuck to the hub, give the drum a sharp smack with the hammer on the front hub face of the drum. Spin the drum 1/4 turn and smack it again if necessary until it breaks free from the hub.

11. Use the spoon and screwdriver as illustrated in Step 8 to turn the star wheel and place the drum back on. Spin the drum to follow your progress. You'll have to keep taking it off and placing it back on to spin in order to adjust them properly.

Tips & Warnings

• Many modern imports use a self-adjusting mechanism that requires no manual adjustments. Simply applying the brake in conjunction with the parking brake automatically adjusts the rear brakes. Tightening the cable on these types of vehicles can usually be done from inside the cab where the handle for the parking brake is located.

References

• AutoMedia: Drum Brakes - Rear Brake Drum Adjustment