What do you mean by running in water? Turning the Fury into a submarine? Splashing through a puddle?
You just got a really beautiful RC; why don't you start by practicing by setting up half empty/full water bottles and make a slalom course, then figure 8's. Then there's the fun of putting electrical tape around the rear wheels and learning to drift. With the tape, you can drift it at lower speeds to get the hang of it.
Just clean up your truck after.
If you think some got into the steering linkage, then it's worthwhile to open and clean it out too.
Suggestion, since you're a noob, like me, take pics with the phone before you dismantle, also consult the instructions before you start. They have some great short-cuts. Or as my Pop would preach, "read the #$%&* instructions first!"
I'm pretty sure your Pop is good at this stuff and a terrific resource, but as a parent can tell you, it's a great feeling to see your kid make good decisions. It makes you want to do more for your kid.
I had the same question for my granite. part of what made me get it was how fun it looked in videos and pictures of the car tearing it up in the mud and puddles. didn't realize how much clean up was in store after...
Ultimate RC discovered in their review of the Fury that despite the labeling, the AS-1 servo is NOT waterproof. I don't know if the ADX-7M servo in your BLX is just labeled waterproof or if it actually is. If you don't know for sure beyond the label that you have a "proper" waterproof servo, then I suggest avoiding puddles all together. Assuming the servo is waterproof, then you need to ensure that the Rx box is sealed correctly. Sometimes in an RTR it's not assembled as carefully as we might ourselves. So I for one would double check that the seal is correctly in place all around the Rx box. Depending on how hard core you're going to get with the water I might even run a very thin bead of silicon along the seal of the Rx box, and where the wires enter/exit it. As far as the motor goes, if it get splashed it's going to just need a wipe down. If it gets submerged, it should be thoroughly cleaned out and the bearings lubed with a light weight oil. I use 3-in-1 myself.