Receiving Helpdesk

why do rotors need to be cut

by Miss Cara Waelchi II Published 3 years ago Updated 2 years ago

Why do rotors need to be cut? A brake pad not fully inserted into the holder could also get "caught" and cause the low pedal issue. Cutting rotors is required when the surface is not uniform - has grooves from old pads.

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.

Full Answer

Why do I need to replace the rotors on my car?

Also, thin rotors are more likely to crack and break apart, which would cause brake failure. Another condition that usually calls for rotor replacement is when the rotors are “warped” and are causing a vibration or pulsation when the brakes are applied.

Why are brake rotors so thin on some cars?

As a rule, most original equipment rotors used to be designed with enough thickness to go two or more pad replacements. But on some cars today, the rotors are thinner to save weight and cost.

Why is the surface finish on the rotors important?

The surface finish on the rotors also is important because it affects the friction characteristics of the brakes, pad seating, break-in, wear and noise. Most new OEM rotors today have a surface finish between 30 and 60 inches RA (roughness average), with many falling in the 40 to 50 RA range.

How do brake rotors work?

As you now know, the brake rotors turn in conjunction with the car’s wheels as they move. When braking pressure is applied to the brake pedal, the pressure mechanically or electronically forces the brake pads to clamp down onto the brake rotor. This friction then reduces the speed of the vehicle. How Long Do Brake Rotors Last?

Do rotors need to be cut?

Most rotors can only be cut/resurfaced once or twice before becoming too thin to continue using. If you only replace pads, they will wear out faster than if you replaced the rotor as well or had it cut. Turning rotors isn't mandatory unless some pulsation or shaking is apparent and/or significant scoring is apparent.

What happens if you don't cut rotors?

If you don't replace the rotors when needed, you risk brake failure and an accident. The rotor absorbs and dissipates heat when the brakes are applied. The thinner the rotor becomes, the more heat is absorbed. This excess heat warps the rotor.Jul 29, 2021

Is it necessary to cut rotors when changing pads?

Like brake pads, brake rotors wear out over time. ... If they are thinner than the manufacturer's recommended thickness, then you need to replace your brake rotors immediately. Some vehicles always require new pads and rotors because the rotors cannot be resurfaced.Oct 24, 2019

Why do you shave rotors?

Rotors resurfacing won't resolve hard spots that come in the cast rotor, as these usually extend well below the rotor surface. Shaving can help remove these hard spots and allow the rotor to run true, but they will eventually return.Jun 15, 2021

Can you drive with pitted rotors?

What happens when you have pitted brake discs? To begin with, pitted brakes won't affect your vehicle's braking capabilities, but they are an early sign of corrosion that - over time - will lead to your brakes becoming less effective.

Can you replace just rotors?

Whether you're replacing both your brake pads and rotors or just replacing one part, you still have to replace them on both sides of the axle. For example, even if just one rotor is worn out and the other one is in good condition, you still have to replace both rotors.

How do you tell if rotors need replacing?

It could represent four signs that it's time to replace your brake rotors.Vibrating Steering Wheel. If you feel pulsing in the brake pedal and vibration in the steering wheel when you slow down, your rotors could be signaling trouble. ... Intermittent Screeching. ... Blue Coloration. ... Excessive Wear Over Time.Jun 28, 2018

What happens if you put new brake pads on grooved rotors?

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.

What is the average lifetime of brake rotors?

between 30,000–70,000 milesSo how long do brake rotors last? It depends. A variety of factors, like your vehicle size, driving style and brake quality, contribute to the lifetime of your brakes. Typically, brake rotors last between 30,000–70,000 miles.Jun 11, 2019

How often should you replace rotors?

between 50,000 and 70,000 milesBrake Pads: When to Replace Them As a general rule, you should get your brake pads replaced every 10,000 to 20,000 miles to keep wear to a minimum. When it comes to your rotors, you have a bit longer. Your rotors should be replaced between 50,000 and 70,000 miles to keep your brakes in peak health.

How much does machining rotors take off?

Myth 4: Two passes make for a better finish. Cutting a rotor in one pass is essential for productivity. For non-composite rotors, it is possible to take as much as 0.020″ per side while still having an acceptable finish.

Why replace brake rotors?

Worn-out rotors are dangerous for two reasons: Thin rotors cannot absorb and dissipate heat as well as new rotors, which increases the risk of the pads getting too hot and fading with prolonged or heavy braking. Also , thin rotors are more likely to crack and break apart, which would cause brake failure.

Why are rotors dangerous?

Worn-out rotors are dangerous for two reasons: Thin rotors cannot absorb and dissipate heat as well as new rotors, which increases the risk of the pads getting too hot ...

Why is my rotor wearing uneven?

Uneven rotor wear and thickness variations can be caused by severe rotor overheating (a dragging brake pad or stuck caliper), by distortion in the rotor caused by uneven torque or over-tightening the lug nuts , or even metallurgical defects in the rotor casting itself .

What is a slotted brake rotor?

Drilled or slotted rotors do add a performance look to any brake system, and they also can provide improved cooling for the rotors and venting for the pads. The holes and/or slots provide an escape path for hot gases that can form between the pads and rotor when the brakes are working hard.

What is composite rotor?

Some vehicles come factory-equipped with “composite” rotors that have a thin stamped steel center hat section mated with a cast rotor body to save weight. This type of rotor tends to be more sensitive to uneven wear and distortion than one-piece cast rotors.

Where is the minimum thickness of a brake rotor?

Every rotor has a minimum thickness or discard specification cast or stamped somewhere on the center hat section of the rotor. When the brake pads are replaced, the rotors always should be measured with a micrometer to determine their thickness. If the rotors are worn too thin and are at or below the minimum or discard thickness ...

Can thin rotors break apart?

Also, thin rotors are more likely to crack and break apart, which would cause brake failure. Advertisement. By. Larry Carley. on. November 29, 2017. Click Here to Read More. Advertisement. Brake rotors may be replaced for a variety of reasons.

Why are rotors thinner?

But on some cars today, the rotors are thinner to save weight and cost. Consequently, the rotors may be worn down to minimum thickness specifications (which is usually marked on the casting itself) by the time the first set of brake pads need to be replaced — or even sooner in some cases.

What causes a rotor to wear unevenly?

But several things can cause a rotor to wear unevenly, resulting in thickness variations that produce an annoying pedal vibration when the brakes are applied.

How does heat affect rotors?

Heat management is another factor that affects both rotor wear and braking performance. When the brakes are applied, friction generated by the brake pads rubbing against the rotors creates a lot of heat. The heat is absorbed by the disc portion of the rotor, and is dissipated by the cooling fins (slotted vents) between the faces of the disc. Vented rotors are almost always used for the front brakes, while vented or non-vented rotors may be used in the back where braking loads (and heat) are usually less. The number, spacing and shape of the cooling fins also is important because some designs are more efficient than others. Replacing original equipment rotors with ones that do not cool as efficiently because of reduced fin count or fin design may cause the brakes to run hot and increase the risk of brake fade.

How often do rotors wear?

The rotors wear every time the brakes are applied. The rate at which rotors wear depends on a lot of variables: the type of brake pads on the car, the metallurgy (hardness and quality) of the castings, how efficiently the rotors cool themselves, the type of driving the vehicle is subjected to, the braking style of the driver (aggressive or easy) ...

What is semi metal brake?

Semi-metallic brake pads usually contain a very high percentage of chopped steel fiber, so they typically cause more wear on the rotors than most ceramic or nonasbestos organic (NAO) brake pads. On vehicles where rotor wear is a problem, switching to a “softer” friction material (such as ceramic or NAO) may solve the problem — provided there’s ...

Why do brakes soar?

Advertisement. Aggressive driving, pulling a trailer, hauling heavy loads or mountain driving all can cause brake temperatures to soar. Over time, this will increase both pad and rotor wear, requiring the brakes to be serviced sooner than would be necessary with more normal or light use highway driving.

How to prevent rotor hat from running out?

Cleaning the face of the hub and the inside face of the rotor hat section with a drill-powered circular brush can eliminate this cause of runout. Hard spots in a rotor casting also can cause uneven wear. The hard spots resist wear while the surrounding softer areas experience more wear.

How does braking affect rotors?

How you treat your braking system will affect your rotor’s life to great effect. Hard stops, resting your left foot on the brake pedal, extreme stops when the brake rotors are still cold, along with environmental factors such as road salt, can all impact your brake rotor’s health. Just as you take care of the rest of your car, ...

Why are carbon rotors used in supercars?

This was partially due to the allure of having racecar technology, but mostly because increasingly speedy supercars needed the cooling efficiency and long-lasting lifespan of carbon-ceramic rotors.

What happens when braking pressure is applied to the brake pedal?

When braking pressure is applied to the brake pedal, the pressure mechanically or electronically forces the brake pads to clamp down onto the brake rotor. This friction then reduces the speed of the vehicle.

How long do brake rotors last?

Conventional steel brake rotors are designed to last up to 70,000 miles, but depending on how you treat them, they could last for fewer or greater miles. Rotors made of carbon-ceramic are designed to last the entire lifetime of a car, although the driver can impact their long-lasting designs, too. Depositphotos.

What is a brake pad?

A brake pad is a small piece of friction material that slots into a brake caliper and, when braking pressure is applied , clamps down onto the brake rotor.

Do rotors have shelf life?

Rotors, have shelf lives and can become warped in their daily use, so you will need to fix them at some point. To demystify the braking system, untangle replacement costs, and explain how long your brake rotors last, The Drive’s bloody-knuckled editors put together this brief guide. Enjoy. That, that is a brake rotor.

Do you have to replace brake pads every time you replace them?

Your brake pads will fade faster than your brake rotors, so no, you won’t have to replace them every time you replace your pads. When you replace your rotors, however, you should also replace your brake pads. Do a rotor inspection every time you replace your pads or rotate your tires. Q.

What does it mean when you use higher quality brake pads?

When using some higher quality brake pads, they will tell you if you are changing from one pad compound to another (either changing brands or product lines) to use new or re-surfaced rotors. This comes into play most often for brakes being used on sports cars for track events and such. Share. Improve this answer.

How to tell if brakes are warped?

Usually you can feel if they are warped through the brake pedal when stopping -- instead of a smooth stop it will kind of vibrate or pulsate when braking at higher speeds. It's very noticeable. This can be measured with a dial gauge and checked against the repair manual's recommendations for "runout".

What does it mean when the brake pedal pulsates?

The pulsating condition felt through the brake pedal is actually pad material burned onto the rotor in one spot. This occurs after a very heavy braking incident which overheats the rotor then the application of the brakes in one spot on the rotor immediately following the incident.

image
A B C D E F G H I J K L M N O P Q R S T U V W X Y Z 1 2 3 4 5 6 7 8 9