i have monster trucks
 

and other cars....im new at this hobby 4 months....how come they dont come waterproof....even if there is a little water on the floor screws up my lst.....lose breaks.....sometime lose control of radio...it start to drive by itself

It's a device with electronics.. you could put it the receiver inside an airtight container and water will still get in there..

It's something you'll just have to live with.. :)

If you want to operate on or in water, get an r/c boat! :)

Seriously, to help prevent failures (as long as you aren't driving in standing water) on wet pavement or mud, spray down everything with WD-40, make sure your receiver box is sealed (like on a t-maxx, put a bead of automotive silicone sealant around the receiver box and then tighten), and make sure your on/off switch is protected (a good shot of WD-40 in there will help).

Good Luck

when we get mad/mud
 

we usually put our receiver inside a baloon/condom then tied with rubberband.....off mud wrestling with other clods