If the cylinder head gasket fails, which is not all that uncommon in Japanese engines; it can then pull coolant into the cylinders and blow it out the exhaust, or pump it into the engine oil. This will cause the coolant level to drop, with no apparent external cause. A head gasket can also become blown if the engine is allowed to heat up into or beyond the red zone on the temperature gauge. Other things that can cause overheating are the electric radiator fan not working; a defective coolant thermostat, or the use of pure antifreeze without mixing it with distilled water. Worn brakes have nothing to do with engine overheating.
Many cooling systems will gradually lose small amounts of coolant over time. If the level is not refilled; in BOTH the radiator and the reservoir, then the engine can overheat. When an engine is losing coolant; it is not safe to just check the level in the reservoir, you must also remove the radiator cap and be sure it is filled all the way to the top. Otherwise, there will not be any siphon action between the radiator and the reservoir. This can cause the radiator level to drop; while the reservoir remains full. And that will make the engine overheat.
When you refill a radiator that has been very low; there may be trapped air pockets left in the system. This air will work its way out during the next day or two; and that can leave the coolant level low again. So you need to frequently check the level, until it either stabilizes, or it becomes apparent that it will not stop going down. If it keeps going down, you need to have the cooling system tested by a professional.
I hope this helps!!!