No. 3 hoistman was pulling lead from 3700-45. Brake not releasing all the way when #1 side in the dump - doesn't release till #2 side in dump. Alarm at 1901hrs. Hoistman acknowledged then reset; 1924 hrs. main drum brake pressure fault on computer. Warning was acknowledged - reset, went to fault again. Hoistman called EE, on site at 2000 hours. Pump coupler seal broke.