While customizing a Peace 150cc I performed the following disc brake removal and service. Although the pistons were not removed this may prove instructive for cleaning and pad replacement. I had removed the front fender, wheel, and axle so it was a simple task to slide the caliper off of the two guide shafts (yellow dots). These fit into the rubber dust boots (red dots) on the caliper. I used a little grease in these on reassembly but obviously only in small amounts. The boots should be inspected for any dry spots or cracks. The caliper on this type of brake "floats" on the guide shaft which allows it to adapt as the pads wear and compensate for small imperfections on the rotor.
Since I was tearing the scooter down to the frame I removed the handle to the caliper as one unit. This is easily done by removing the pinch bolt on the handlebar.I then drained the brake fluid out by removing the reservoir cap and loosening the bleeder valve.
Then hold the caliper higher than the reservoir and drain into a container.
The next thing I wanted to do was remove the Chinese "ABS" valve. This is nothing more than a pressure relief valve and should not be confused with an actual ABS. I put the valve in a vise and used a socket to remove the banjo fitting. If you're careful you can use the seal washer again after removing the brake line:
Then I carefully secured the caliper in a vise and removed the valve with a crescent wrench:
Next, check the brake pads for thickness. The conventional wisdom is that they should be thicker than a dime.
I removed mine completely which I feel gives you a chance to inspect them in more detail. To remove the pads take the two allen bolts out.
This allows for the pads and tension spring to be removed. The "pucks" are the inside of the brake pistons. I opted to leave the pistons in the caliper since things looked relatively clean and the brakes were working fine. Quite a few people have posted on the forum with problems getting the pistons back together after disassembly.
At this point I sprayed all the parts with brake cleaner and wiped them down. Be careful, this stuff is nasty and you'll get sick from the fumes in no time. I also removed the beeder valve and sprayed the inside of the caliper. I didn't soak things down since I thought it might not be great on the inside of the pistons.
My pads looked good so it was time to reassemble everything. The only tricky part is getting the pads into the tension spring correctly. The spring has two tabs on it that hold one of the pads in place.
to be continued......