Chinese motor scooters are relatively inexpensive yet incorporate surprisingly sophisticated technology. For example, they have complete electric starting, charging, directional and lighting electronics that rival small cars. They also have front and rear caliper disc brakes with ventilated disc rotors and ball-bearing-enhanced lead screw actuators that multiply hand-braking force many times to assure quick, safe stops. Replacing the front brake pads on a Chinese scooter is a straightforward project.
Put the scooter up on a cycle hoist, or lift the front of the scooter onto a small bench or stand. The front wheel should be free to spin.
Use a metric Allen wrench to remove the two socket head machine bolts holding the disc caliper assembly on the scooter. The assembly should include the wear compensator bracket. You should not need to disconnect the front brake actuator cable from the caliper assembly.
Use a metric Allen wrench to remove the two socket-head machine bolts holding the rear caliper casting to the main caliper body. Hold the assembly together and drop out the screws, pads and old separator spring. This spring looks like a small hairpin. It holds the pads apart when not braking so the disc can spin freely. Replace it too, because brake heat gradually diminishes its spring rate.
Take the caliper actuator assembly apart over a pan lined with foil. There will be a lead screw with a follower that has small depressions to hold three small steel balls. There will also be a one-piece disc with a post that sits inside the caliper. Clean all parts with penetrating oil, and wipe them completely clean and dry with a clean shop towel. Keep these small parts inside the pan while cleaning, as you can easily lose them.
Rotate the front wheel while taking the glaze off both sides of the brake disc with the emery cloth. Inspect the disc for warping or bending; it should spin straight and true.
Clean your hands and reassemble the caliper the way it came apart. Put a coating of the anti-seize lube on the bearing balls and inside their retention cavities.
Push the posted disc against the balls, and mount one of the brake pads. Position the other brake pad into the back caliper piece, and position the ends of the small spring into the notches in each pad.
Bolt the rear caliper piece back onto the front assembly and tighten.
Mount the front caliper assembly back on the front fork. Make sure the brake disc slides easily between the two brake pads. Spin the wheel, and squeeze the front brake handle on the handlebars. The wheel should stop immediately and smoothly.
Take a ride and test the front brake. It will take a few days of use to complete the wear-in process. The brake may need a slight adjustment, which you can do by shortening the cable end at the actuator.
Take the opportunity to thoroughly clean the inner caliper parts. Adjust the disc depth screw so the brake doesn't drag while driving,
Put a drop of locking compound on the bolts so they will not vibrate back out and cause brake failure.