When you tighten wheel nuts, you hold the wheel on the axle your tightening the nut on. If the hex on that wheel is stripped, then you have to replace the wheel.
Since it's a savage X and not knowing what servo you have (strength/speed), one of the steering posts has a spring on it. Below that spring is a nut. If you tighten that nut up some, it will stiff up the servo saver and if your servo is strong enough, it should steer better.
This is an older non-X savage, but also has a servo saver you can adjust on the right, near the bottom under the silver spring is a knurled nut that you loosen or tighten to soften up/stiffen steering:
Brakes could be a few things...
servo shaft or horn could be stripped
servo itself is too weak or damaged internally/electronically
the spring loaded servo horn could be faulty
brake disk is worn down too much
screws holding the brake pads in place could have backed out or stripped not allowing force to be applied to the disk
linkage isn't setup right
your radio doesn't have the EPA setup right not allowing the servo to move far enough.
Many replaced the stock servo horn with a solid horn, then used springs/collars on the brake linkage to do the same job, but more effectively and to be more adjustable. I never used the stock servo horn on any savage I owned, I always replaced it with a solid horn and used springs/sliders/collars on the brake wire.