What Causes Grooves In Brake Rotors?
Are grooves in brake rotors OK?
However, a groove to make you grieve – and a clue to your rotors being on the way out – is the presence of scoring or grooves on the rotor's surface. Such marks are the product of time and usage and, while degrading in this way is perfectly normal, it's also a signal your rotors are due for replacement.
Should my rotors be smooth?
Over time, your rotors will also wear down and you may find the pads have created a slight groove in the rotor. This is very harmful to the rotor and this must be avoided. A healthy brake rotor will be a smooth and uninterrupted surface, free of dust, grooves and grit.
Can I drive with grooved rotors?
Groove marks on the brake discs may affect its ability to slow down the vehicle. Bad rotors may also cause the vehicle to vibrate, which may create the scary sensation that the car is not going to stop altogether. The inability of the brakes to stop the car can be extremely dangerous, especially during high speeds.
Scoring usually occurs when the frictional material on the brake pads has been worn down severely. Once this “padding” is gone, the underlying metal scrapes against the rotor during deceleration. Over time this can lead to deep grooves on the rotor surface.
Deep grooves in rotor
Brake pads that are severely worn down often leave deep, circular grooves in the rotor. If such grooves are visible, brake pads and hardware must be replaced, and rotor service or replacement will also be needed.
If your brake rotors have sufficient metal remaining with no hard spots, cracks, severe grooving or rusting, then the rotors could be resurfaced. Some have the opinion that unless the brake rotors have surface issues needing to be fixed, the rotors should not be resurfaced every time the pads are replaced.
Unlike other vehicle problems, warped rotors will only cause your vehicle to shake when you are braking. If you are experiencing shaking during acceleration, you likely have a different vehicle issue, such as an alignment or balancing concern (more on these below).
If there is enough thickness left in your rotors when you go to have your brake pads replaced, some shops will offer to resurface your rotors on a machine (called a lathe) to bring them down to a smooth surface for the new brake pads to wear against.
Resurfacing Your Rotors
Sometimes your rotors may need to be resurfaced because they have worn unevenly, warped from heat, or become damaged by worn brake pads or pitted from corrosion or rust. Resurfacing rotors removes some of their metal, until the surface is smooth and even again.
Brake rotors should last a minimum of 50,000 miles (80,467 km). The average life expectancy for a quality set of rotors is 30,000 to 70,000 miles (48,280 – 112,654 km). Brake pads have a similar long life-span, but it's not typical to see more than 70,000 out of a pair of Rotors and Pads.
Ideally, you should have your brake pads replaced between every 10,000 and 20,000 miles, and your rotors replaced between 50,000 and 70,000 miles.
It's usually a good choice to have your rotors replaced with your brake pads, since worn rotors don't work very well, even with new pads. You can expect to pay between $30 and $75 per rotor and between $150 and $200 for the labor for each axle, for a total of between $250 and $500 per axle.
If your brakes emit a sharp grinding sound while braking, it's likely that the brake disc and the caliper are rubbing together. The sound is usually heard when you stop your car, but you may also feel the brake pedal rumble as you step on it.
Glazing is where the brakes have been heated to the point that the material within the brake pad hardens and smooths to the point that it mirrors and can no longer create effective friction against the rotor.
Warping actually just refers to an uneven surface, mainly caused by heat. The brake rotors can be warped in the following ways: The brake rotors can become glazed with material from the brake pads. This happens when the brake pads get very hot which causes the pad material to rub off onto the brake rotors.
Over time, brake pads accumulate oil, dirt, or other materials. When this happens, the substances can cause vibrations, particularly when you press the brake pads. Also, over time the rotors get thinner, making them susceptible to damage. During braking, excessive heat is generated and can cause the rotors to warp.
If this is caught early on, you can possibly remedy it by bedding in your brakes with a more abrasive pad, or resurfacing your rotors. If the heat spots are extensive, you will need to replace your rotors.
Brake Pad Engineering
Braking generates heat, which can vaporize water or materials in the brake pad. Grooves allow these vapors to escape. Braking also generates vibrations, some of which occur in our hearing range.
Your rotors can be turned (rotated), machines and still be within factory guidelines, but this usually leaves them thin whereby leaving them to warp or vibrate. The cost for turning a rotor runs anywhere from $15 to $25 per rotor.
Death wobble is used to describe a series of sudden, often violent front suspension vibrations exhibited by solid front axle suspensions, and more infrequently, independent front suspensions.
The most common cause of vehicle wobbles in this speed range is a bent wheel or mildly out of round tire. Transmission and drive line issues can also show up in this range, but tires are the first thing to check. Unlike the low speed wobble, this is usually not a safety issue.
Sometimes brake rotors can be the cause of shaking. If your steering wheel shakes while you are braking then the problem could be caused by “out of round” brake rotors. This vibration can also be felt through your brake pedal.
Anything below 10.5 millimeters and you will want to buy a new one instead. In most cases, you can get away with resurfacing your brake rotor twice before it will become too thin and require a replacement the next time it performs poorly.
Those severely damaged rotors usually need to be replaced, not resurfaced. Some vehicle manufacturers even require that you replace your rotors rather than resurface them. Otherwise, most industry experts suggest that you should replace them every 30-70K miles.
How Much Does It Cost To Turn Rotors At AutoZone? AutoZone can charge up to $25 per rotor for this service but often suggest a total replacement citing cost-effectiveness.
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If new brake pads are put onto a vehicle with damaged rotors, the pad won't properly contact the rotor surface, reducing the vehicle's stopping ability. Deep grooves that have developed in a worn rotor will act as a hole-puncher or shredder and damage the pad material as it is pressed against the rotor.