Auto Repair: Brakes & Rotors

If the rotors are warped causing the steering wheel to shimmy when the brakes are applied, can the rotors be “turned” (i.e., machined down) to fix/minimize this? Or, do the rotors have to be replaced, regardless?

Naturally, this question assumes the rotors have enough life left that they can be “turned” to a reasonable degree. - Jinx

Some rotors are manufactured so thin the manufacturer recomends only one turning before replacement.

In such a case a severely warped rotor should be replaced from the get-go.

The answer is maybe.
some car makers do not recommend the turning of rotors. Others do.
What can happen is the rotor after turning has less mass, and will re warp sooner rather than later.
Also on some designs the hub (which locates the rotor) can get warped due to excessive torque on the lug nuts. No amount of rotor turning is going to correct a warped hub. In fact even a new rotor won’t fix this. Only a new hub will.
Without specific year make and model there doesn’t seem to be much else I can tell you.

In some cases it’s actually cheaper to buy new rotors than have the old ones turned. (IIRC, new rotors for my car were about $10 each.)

You can try the following, sometimes it works:
Get up to about 70mph, hit brakes HARD till you get down to about 15mph (Don’t stop unless you have to)
repeat 2x

What the above assumes is the rotor is not warped but some brake lining has fused onto the rotor causing the shimmy. The above will heat up the rotors enough to redistribute the ‘stuff’.

If 70 MPH is not practical you can substitute a steep hill and lower speeds.

Thanks all for the thoughts! I have this stigma that rotors are so expensive. I’ll look into whether it is cheaper to simply replace, and if replacement IS the only option, regardless!

Great feedback like this is what makes the SD such a great place!

I pop on new rotors every 2 years at $19 each.