How to Adjust Self-Adjusting Brakes?
2 Answers
On the inner side of the caliper brake pump, you can see a bleeder screw with a cap. Rotate it counterclockwise, and oil will start to leak out. After letting the oil drain for a few seconds, tighten the screw again. Then, repeatedly press the brake pedal in the cabin several times and hold it down. At this point, loosen the bleeder screw again, let the oil drain for a few more seconds, and then tighten it. Repeat this process several times to achieve the desired brake adjustment effect.
Having driven trucks for so many years, I find self-adjusting brakes quite convenient, though sometimes manual adjustment is necessary. Park the truck on level ground, engage the parking brake, and use a wrench to turn the hex nut inside the wheel. Tighten it clockwise until the wheel can't rotate at all, then loosen it counterclockwise by about half to one full turn—the wheel should spin freely but with slight resistance. Make sure all four wheels are adjusted to the same tightness, or the brakes may pull to one side. After adjustment, test the brakes by pressing them several times to allow the automatic mechanism to re-engage. If the brakes loosen again within a few days, it's likely the adjustment spring is worn and needs replacement. This job is best done with two people: one adjusts underneath while the other presses the brakes inside the cab to check the effect.