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Brake rotors may be replaced for a variety of reasons. One is that replacement is a must if the original rotors are worn out. 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 (or they cannot be resurfaced without exceeding the limit), the rotors must be replaced.
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.
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. Warped is actually a misnomer, because the rotors are not distorted but are worn unevenly. When there is more than a couple thousandths variation in rotor thickness, it pushes the pads in and out when the brakes are applied. The force is transmitted back through the caliper pistons, brake lines and master cylinder all the way to the brake pedal, creating a vibration or pulsation that can be felt by the driver. The greater the variation in rotor thickness, the stronger the vibration or pulsation. It’s a really annoying condition, though not necessarily an unsafe one. It may be mistaken by the vehicle owner for a problem with their antilock brake system, which also can produce pedal pulsation or vibrations when the ABS system kicks into play.
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. High spots on the rotor will often be discolored with a dark bluish tint. Resurfacing the rotor can restore flat parallel surfaces, but often the hard spots that are caused by overheating or uneven wear extend into the metal surface. Over time, this will cause uneven wear again and the pedal pulsation or vibration to return. Replacing the rotors with new ones eliminates any such worries.
Rotors also must be replaced if they are cracked, damaged or severely corroded. The danger is rotor failure due to the cracks or severe corrosion. Some minor heat cracking on the surface may be acceptable, but heavy or deep cracking is not.
Another reason to replace rotors is to upgrade braking performance and/or the appearance of the vehicle. 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. Holes and slots or wavy grooves in the rotor face also create turbulence, which improves airflow and cooling.
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. Composite rotors also are more costly to replace, so one-piece aftermarket cast rotors are a replacement option. However, if replacing composite rotors with one-piece castings, both rotors (right and left) should be replaced at the same time to maintain even braking and alignment side-to-side. On some vehicles, replacing a composite rotor with a thicker cast rotor also may alter wheel geometry slightly, creating increased toe-out and tire wear when turning.
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It used to be common for mechanics to rebuild certain components in the shop, including brake calipers, wheel cylinders, starters and alternators. There used to be a time when economically it made sense. The small components needed for a rebuild were inexpensive, and it ultimately didn’t take too long. Plus, all you could get was the rebuild parts, or go with new.
But the repair industry shifted away from rebuilding. Now, professional technicians rarely toy with the idea. But what about brake calipers? Does it make sense to rebuild them instead of replacing? Most of the parts are readily available. If the professionals don’t do it, why not? And, can it save money for a DIYer?
The knee-jerk answer for many is no. The main reason is time versus cost. Let’s face it: Remanufactured calipers are very reasonable in price. Companies that do this benefit from volume. Every part of the process from cleaning to inspection, machining and reassembly happens in volume, so they’re able to keep the costs low, yet produce a quality product. It’s difficult to justify the amount of time it would take, especially when you consider the cost of your labor.
Is it difficult to do? Not by any means. A brake caliper is possibly one of the easiest things to rebuild – even rear calipers with built-in parking brake mechanisms. It’s the same basic process (just a few more parts), so you just need to pay closer attention to how they come apart.
But, there are a few questions to ask. Do you have the means to clean and refinish it? Do you have the tooling to properly hone the piston bore? And then you need the seal kit and possibly a new piston. To match what you get with most reman calipers, add new slide pins, boots, pad shims, a new bleeder valve and new brake-hose sealing washers into the mix.
When you consider the time and effort involved, suddenly it starts to sound a little better to go with a reman or new, and the best part is, new calipers aren’t much more expensive than reman.
With all that said, why would someone rebuild a caliper? Rebuilding can be fun and it’s a rewarding feeling. Even though it’s not cost-effective from a professional standpoint, for a DIYer it can save a lot of money. If it’s a project car and time is not of the essence, saving money is usually the name of the game.
Remanufactured calipers are always refinished, but maybe there’s a specific color you want the calipers to be. High-heat caliper paint is readily available in many colors, and if you’re going to paint them, the proper time to do it is when they’re disassembled.
In some cases, on older cars, reman or new calipers may not be available. There aren’t any cores to rebuild, and it’s cost-prohibitive to produce new ones, so you may have no choice on some restorations. There also are cases where a specific type of caliper – whether it be the design or specific casting marks – may affect the originality of a car, and this also is an important part of the restoration.
There are plenty of reasons to rebuild a caliper, and there’s certainly nothing wrong with doing it. But, it’s safe to say that most are going to go with reman or new options unless the circumstance calls for using the original.
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The replacement of link hidden, please login to viewis an important part of car maintenance, as the condition of the brake pads directly affects braking performance and safety during travel. When it is necessary to replace worn brake pads, it is generally recommended to replace the brake pads on both the front and rear wheels together.
Actually, in most cases, it is not necessary to replace the brake pads on both the front and rear wheels together. The wear and link hidden, please login to view of the front and rear brake pads are usually different. Under normal circumstances, the front brake pads experience greater braking force, resulting in higher wear and shorter lifespan. They typically need to be replaced around 30,000 to 50,000 kilometers. On the other hand, the rear brake pads endure relatively less braking force, meaning they last longer. Generally, they need to be replaced around 60,000 to 100,000 kilometers. When replacing brake pads, it is important to replace them together so that the braking force on both sides is balanced.
If both the link hidden, please login to view and link hidden, please login to viewhave a certain degree of wear, it is also possible to replace all four of them together.
When should brake pads be replaced, and how can you perform a self-check on them? Here are the methods:
Check the thickness: A new brake pad typically has a thickness of around 1.5 cm. As they wear over time, the thickness of the brake pad gradually decreases. Professionals recommend that when visually observing that the brake pad thickness is only about 1/3 (approximately 0.5 cm) of its original thickness, it is advisable to increase the frequency of self-checks and be prepared for replacement. Each brake pad has a raised indicator on both sides, with a thickness of around 2-3 mm. This indicator represents the minimum thickness for brake disc replacement. If the brake pad thickness is level with this indicator, it must be replaced.
It is indeed important to consider individual driving habits and environmental factors when determining the replacement interval for brake pads. While a general guideline is around 60,000 kilometers, it is advisable to have them inspected by a professional technician during regular vehicle maintenance when visually observing that the brake pads are thinning. This is because visual inspection can sometimes lead to errors, and a thorough examination by a qualified mechanic is more accurate and precise.
Listen for noises: If you hear a "squealing" sound when lightly applying the brakes, it could be an indication of the initial interaction between the brake pads and the brake rotor upon installation. In such cases, it is recommended to replace the brake pads immediately because they have already reached the limit where the indicator on both sides of the brake pad is directly rubbing against the brake rotor. When encountering this situation, it is important to inspect the brake rotor while replacing the brake pads. The occurrence of this sound often suggests that the brake rotor has been damaged. Even after replacing the brake pads, the noise may persist. In severe cases, it may be necessary to replace the brake rotor. Additionally, the quality of the brake pads can also contribute to the occurrence of such noises.
Therefore, once unusual noises occur during braking, if it is not caused by the brake pads, it is possible that excessive wear of the brake pads has led to direct contact between the brake pad indicator and the brake rotor, resulting in damage to the brake rotor. The cost of replacing a brake rotor is higher than that of brake pads. Therefore, it is advisable for vehicle owners to develop a habit of regularly observing and promptly replacing brake pads when necessary. This will help prevent potential damage to the brake rotors and ensure optimal braking performance.
If you feel a lack of braking power when applying the brakes, it is possible that the brake pads have significantly lost their friction. In such cases, it is crucial to replace the brake pads to avoid potential serious braking accidents.
Therefore, it is important to develop a good habit of self-checking. Additionally, decreased braking performance can lead to increased consumption of brake fluid. Therefore, when replacing brake pads, it is necessary to check the condition of the brake fluid as well. and you should change good quality link hidden, please login to viewor link hidden, please login to view.
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If new brake pads make noise at low speeds, it's often because the old brake pads have worn the brake discs. The complete solution is to polish the disc, but if that's not possible, a temporary solution is to polish the brake pads. If there's a sudden noise after driving for a period of time, the foreign objects causing the noise should be removed. If there's a rattling sound regardless of whether you step on the brake, the brake accessories should be properly installed.