Timing belt question

I'm doing my timing belt this week and wondering if I need to replace all the rad fluid? Do I drain the whole rad when doing it or just the top hose?

 

i would replace the water pump while i was at it

 

I think you would have to drain it all to drain the water pump.

 

Just let it spill out of the water pump when you replace it. It will drain faster.

 

If the antifreeze is still good just drain it in a clean 5 gallon bucket, and pour it back after you hook the radiator back up.