03YZ450F I'm assuming it's probably the master cylinder. Just want to try and make sure before I buy a rebuild kit. It worked fine last time I used it. I tried to close the caliper after replacing the wheel and nothing. Fluid lvl is good, I tried bleeding it and it just oozes out. The piston barely moves when I pump the brake lever sometimes even moving back in. When it finally closes up on the rotor there is no presure. When I open the bleed valve on the caliper and push the piston back fluid squirts out like it should. Not sure how to test which one is bad but a master cylinder kit is far cheaper then a caliper. Sound like the master cylinder is just worn out?