i have a 96 na supra..since recently when i run the car for prolonged periods for about 3 hours or more the engine tends to over heat. and when you shut it down you can hear the coolent bubbling in the hoses..i have checked the head gasket replaced the thermostat and done a full radiator flush but the problem still persists..does anyone know what i can do to fix the problem???and also the hand break and warning like come on inadvertantly..how can i fix that?? thanks

Check the water pump, the car tends to overheat if you drive at high RPM usually, or when you take turns, the shaft is being bent by the driven pulley belt that put more stress when you drive hard, or even at relatively high RPM. Make sure you replace it with NA water pump and not a TT one.