If the brake fluid reservoir is overfilled, the excess fluid runs through the overflow instead of over the bodywork, which would cause damage to the paint work.
Sounds like the rubber line on the bottom of reservoir is leaking or tank is cracked CHECK IT OUT.
Steering pump fluid may overflow from the reservoir due to overfilling, which can occur if too much fluid is added during maintenance. Additionally, a malfunctioning pressure relief valve or a blockage in the return line can cause excess pressure, leading to overflow. Air in the system can also create bubbles, resulting in fluid expansion and spillage. Finally, a failing steering pump or a leak in the system may contribute to fluid overflow.
As time passes water in the fluid evaporates and needs more so it Will suck it out of the overflow. It Will also dump it into the overflow if it overheats.
broken radiator
1 simple cause may be a damage radiator cap or simply low fluid.
Low oil causing the coolant to heat up to the point in which it's doing more harm than good so it's pushed into the overflow
NO. It is just an overflow reservoir. I would however fix that crack. There are many products to repair plastic. Plast-Aid is one. You can also find a replacement reservoir at your local salvage yard.
It depends on what you mean by "run out" but there is probably a leak in the tank.
If you put the brake fluid in the overflow reservoir just empty the reservoir and pour in a 50/50 mix of antifreeze and distilled water. If however you put it in the radiator itself, I would recommend you drain the radiator and refill. Brake fluid is corrosive and may damage the water pump seal.
possibly a leak in cooling system
There is no hydraulic fluid in the transmission. However, there is hydraulic fluid in the clutch system. If the clutch fluid reservoir is empty it would cause clutch not to operate.