I am working on my brothers 2003 wr450 getting it ready for the riding season. I was bleeding the brakes and a big air pocket came out of the line, after that the fluid stopped moving. piston in the caliper wont move and the fluid wont pump through the master cylinder. I emptied out everything, the line, the cylinder and the caliper of fluid. I tried to refil but the fluid doesnt move. Do I have to rebuild the master cylinder, or am I missing something? Thanks for all of the help