Time for an inspection at a tire and alignment shop. In particular it sounds like you could be describing lower control arm bushings. The rubber part can make a creaking noise when it slides slowly on a metal part and has weight on it, but they're often quiet when they slide quickly as in over bigger bumps at higher speeds. Often you just can't hear them at higher speeds.
Inner anti-sway bar bushings can squeak too but they will have less tendency to do that when driving straight ahead. There is only tension on them when the steering system is turned to one side. Lower ball joints can make noise when they're worn. It is indeed possible for front brake rotors to cause a crunching noise but that almost always happens right after a low-cost brake job or one that is done by an inexperienced mechanic who hasn't learned the many tricks used to prevent those noises. A warped rotor can cause a brake caliper to slide back and forth on its mount. That's why those mounts are designed that way, but if the special grease wears off or wasn't applied during a brake job, you might hear the rubber inserts sliding over the mounting bolts. That will make more noise during braking when there's more force on those bolts, but if the rotors are warped bad enough to cause that kind of noise, you would notice a shimmy in the steering wheel or feel a pulsation in the brake pedal.
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Wednesday, January 11th, 2012 AT 4:27 AM