RE: Cracking, Crunching Servo???
It's always a good idea to replace steering servos upfront or soon after you buy your kit. You should look into getting metal gear servos for your steering since they tend to take a lot of punishment. You can spend $15 or $50 on servos and even more if you want. I buy cheap metal gear servos off ebay for around $15 and they hold up well.
I have taken apart a stock plastic gear servo apart before and spun the broke gear around so it wouldn't grind or crunch. Just a quick fix while waiting on parts. If you do this just be careful to replace the gears like they were or your servo wont work at all.