What was found
WHILE HOLDING SHORT OF RWY 06 IN TEB THE ANTI-SKID INOP/LOW BRAKE PRES. CAUTION LIGHT CAME ON, WE ACCOMPLISHED THE QRH CHECKLIST. WE TAXIED BACK TO SIGNATURE SOUTH, DURING THE TAXI LOST ALL MAIN BRAKE CONTROL PRESSURE,I USED THE EMERGENCY BRAKES TO STOP THE AIRCRAFT & HAD SIG-S BRING A TUG TO TAKE US BACK TO THE RAMP SAFELY. THIS IS A REPEAT WRITE UP. CORRECTIVE ACTION: REMOVED AND REPLACED HYDRAULIC PUMP MOTOR IAW MM 32-44-20. REMOVED AND REPLACED HYDRAULIC PUMP LOW PRESSURE SWITCH IAW CE560XL AMM 32-44-20 AND WDM 32-40-01. DURING REPLACEMENT OF SWITCH FOUND EXPOSED WIRE STRANDS, REPAIRED PER SPM 20-30-25. OPERATIONAL CHECK AND TAXI CHECK SATISFACTORY PER AMM 32-44-20, 32-44-00 AND WDM 32-40-01.