I have an SDS bit that will not release from my Hilti...any idea how to get it out?

By disassemble the chuck parts to get the ball out and all blocking parts , when the drive guiding the bilt lock is worn it will be happens again in a short time or you have used a wrong chisel ? the where safety glasses after the dissassembling and place the chisel with tool complete on it in a big bench vice and make the dissassembled bitholder hot carefully with a burner and beat the machine from the chisel only if all blocking parts are disassembled or totally removed replace the
chuck parts but also the entire shaft guide if it is simply worn out by wrong chisel not.