Hi,
my son has polaris scrambler 400 95 model.
I noticed there is exesive play on the front hub,it looks the
bearing is worn out. the 4*4 is working ok.
how difficult is to replace both sides do I need special tools?

 

The only special tool you will need is a torque wrench. You may try to tighten it up before you replace them. 100 inch pounds.
You dont want it too tite or you will create a "drag" in the hub, causing it to lock in at high speed. not pretty.