So when I'm braking on the highway or from high speeds, my steering wheel shakes like crazy. I'm not really a car-savvy person so I don't really know what could be the problem. I've been doing research and seems like its the rotors. How can I know for sure and how much do you think it'll cost me?


08 Mazda3

 

Rotors are a good bet, however, the price for the repair can vary fairly significantly; best if you shop around a bit.

 

If you feel it in the brake pedal then rotors.
Steering wheel shake, it might just be an out of round tire or bent rim. The only solution for this last one is to replace the tire, tires or bad rim.
If it only happens when you are braking hard then another possibility could be a problem in the ABS system.

 

^^ What they said. If it's the rotors then likely one or both are warped. Theoretically this can be fixed by having the rotor faces machined...... i.e. shave down the high spots. That said they can only be machined if there's enough face left on them. If your front pads are to the point where they need to be replaced anyway you might as well do that and replace the rotors at the same time. Parts for the front brakes can run $200-300 for DIY depending on where you find the parts and what you buy. If you have some basic hand tools you can replace the pads yourself without too much fuss.

Like Richard said you could also have a bent rim that's causing the issue. You could rotate the wheels and see if the problem persists, or if moving the wheels makes the shaking change at all. If it does move or stop then the issue is likely with a wheel itself.

 

I brought it into the car dealer I bought it from and they machined the rotors and it fixed the problem They did it for free too

 

Don't be too surprised if the problem returns in the next few thousand miles; your rotors are now thinner after the machining process, and as a result will be rather more suceptible to developing hot/hard spots and/or warping yet again. Next time simply have them replaced.

 

How much does this typically cost? Are there different types of rotors?

 

Figure $50 per wheel for decent quality rotors, and up from there for higher quality units. Unless you're tracking your car you won't need to buy the more expensive rotors.