Review on 🏎️ Optimized Hydraulic Brake Master Cylinder for Go Kart Buggy - 90cc, 110cc, 125cc, 150cc, 200cc, 250cc | Hammerhead Twister, Sunl, BMS, Kandi, Roketa, Taotao, Kazuma, Kinroad by Kenny Donald

There is a raised circular surface around the pistons that protrudes slightly through the master cylinder mounting surface. It's a millimeter or two in diameter, so it needs to be lightly filed to fit through the hole in the mounting surface. The master cylinder has two hydraulic circuits with separate pistons. I advise you not to connect the brake pedal until you have completely bled each circuit individually. If the brake is applied at the brake pedal, bleeding one circuit will harden the pedal and prevent the necessary brake pedal travel to bleed the other circuit. I made that mistake. To successfully bleed, I left the brake pedal released and used a Phillips screwdriver or a socket extension to push on each piston and perform the bleed procedure on each respective wheel bleeder valve. This isolates the pumped circuit and fully utilizes the master cylinder piston until all air is expelled from the circuit. Once all the air was out of each wheel pipe caliper and both pistons were holding strong pressure, I connected the brake pedal. (This is just advice, I learned it the hard way. I do not guarantee my advice will work for you, and I take no responsibility for my advice. This is just an illustration or observation of what has worked for me This in no way guarantees you success and assumes you have previously bled the brakes and know exactly what you are doing when you bleed the brakes.) After the master cylinder mounting surface has been modified slightly, installed, bled completely and the brake pedal has been installed reinstalled, works great. The brakes work great now. The parts price was low. It works fine, but it took some effort to get it working. The part didn't fit at first.