The air crew were detailed to carr out a regular cargo msn on route Bunia to goma in C-130B ac ser no 0962.During the takeoff roll,after 60 knots, capt shifted his hand to flt con leaving the nose wh steering as the normal procedure. but at about 80 knots the ac suddenly swung to the left,the capt immediate decided to abort the msn and ac control by applying differential braking with the help of the co-pltand nose wh steering input. Finaly we suspected that nose steering control valve malfunction during ac speed 80 knots. What might be the reason can anyone inform. Thanks in advance.