My car is leaking water and constantly cutting off when Im on the brake what can I do to fix it.

Your question: "I have a 1990 Toyota 4runner &, I just recently had a tuneup but last night it start smoking and cut off but it was more like steam,this morning I put water in the car & left it running bout 45 mins and now it cuts off when I hit the brake at anytime & leaking water