Hit up youtube/google.

I have waterproofed crawler escs before, but this is different. Heat will buildup unlike the crawlers.

For the receiver: Have leads sticking out of the receiver to have a servo/esc lead plug into. Epoxy the whole thing; cover every seam, hole, led light, everything. I have submerged my cars using this method.

For a *crawler* esc: This will gurantee overheating in the MT4 esc. Epoxy the whole thing just like with the receiver. (I can't help much with this. Hit up youtube/google or the electronics subforum here).

Servo: Doesn't need as long as you are not submerging the whole thing. Maybe epoxy the seams on the side and put marine grease on the gears.