Q: how do you know if you need to replace rotors

asked by on

I don"t seem to be having any problems braking. just replacing pads for the first time. my mechanic just said I needed to replace them.

My car has 62000 miles.
My car has an automatic transmission.

When brake pads are replaced, the brake rotors MUST either be re-surfaced on a brake lathe OR the brake rotors must be discarded and new rotors installed. If the old rotors are NOT worn below the legal minimum thickness, and are not otherwise damaged (scored or warped), the least cost option is to re-surface the rotors on a brake lathe. Most aftermarket rotors are junk made in China. If you buy new rotors because the old ones cannot be re-surfaced, I strongly recommend you install ONLY the OEM rotors from the dealer or rotors from a reputable name brand such as AC Delco. The reason that rotors can never be re-used as is, no matter how they appear to the eye and no matter what your present braking experience is, is because a variation in thickness in the rotor that exceeds just .001 inches WILL be felt as pedal pulsation and vibration. In comparison, a human hair is FOUR TIMES that value (a hair is .004 inches thick). In other words, the brake rotor must be perfect and I can guarantee that if the rotor is used, it is far from adequate for re-use (without re-surfacing at minimum) with brand new brake pads. In addition, once the rotor is re-installed on the wheel hub, the total installed rotor run out must NOT exceed .002 inches. Ask your mechanic to use a dial indicator to confirm that and if run out exceeds .002 inches the rotor must be re-indexed, shimmed or replaced (or the cause of the run-out found and repaired). Certified mechanics from YourMechanic install new pads and rotors on a mobile basis thus saving you a lot of money. If you desire that service please request brake service - new pads and rotors and the responding certified mechanic will get this taken care of for you. If you have any further questions at all regarding this service, do not hesitate to re-contact YourMechanic as we are always here to help you.

Was this answer helpful?

Need advice from certified mechanic? Get help now!

Over 1,000 mechanics are ready to answer your question.
The statements expressed above are only for informational purposes and should be independently verified. Please see our terms of service for more details
  1. Home
  2. Questions
  3. how do you know if you need to replace rotors

Get an instant quote for your car

Our certified mechanics come to you ・Backed by 12-month, 12,000-mile guarantee・Fair and transparent pricing

Get a quote

What others are asking

Q: Front rotors are wearing way too fast

Brake performance and wear reduction are two very popular modification questions for most vehicles. There are many options available that can extend the life of the rotors and/or pads. Look for rotors that are drilled and/or slotted. These types of...

Q: Whistling when the car is turned off, throbbing hum at 80+mph

Hello. It sounds like you have a few issues here. The noise that occurs when the vehicle is turned off typically comes from one of the engine's accessories. It can also come from a timing belt issue, such as the...

Q: brake and abs light won't go off after replaceing brake pads and ft. rotors.

Your car is equipped with wheel speed sensors at each of the four wheels which monitor wheel speed while relaying this information constantly to the ABS and traction control system which are controlled by the car's ECU. When the ECU...

Related articles

What Causes Hoses to Leak?
While the largest part of your engine is mechanical, hydraulics plays a significant role. You’ll find fluids at work in a number of different areas. Your car's fluids include: Engine oil Transmission...
P0240 OBD-II Trouble Code: Turbocharger Boost Sensor B Circuit Range/Performance
P0240 code definition Turbocharger Boost Sensor B Circuit Range/Performance What the P0240 code means P0240 is an OBD-II generic code triggered when the Engine Control Module (ECM) detects the intake boost...
How to Avoid Back Pain in a Car
If you have back problems, sitting in a car for an extended period of time can be excruciating. Even without back problems, you could experience discomfort and soreness from...