What material are the rear brake discs of a car made of
The common materials for the rear brake discs of cars include the following types:
Gray cast iron (HT250
Gray cast iron is currently the mainstream material for brake discs. It has a carbon content of 3.1%-3.4%, a silicon content of 1.9%-2.3%, and a manganese content of 0.6%-0.9%. It features high hardness (187-241 HBS) and tensile strength (above 206 MPa), and is cost-effective and wear-resistant.
Alloy material
It is made of metals such as copper, zinc and aluminum, featuring light weight, high hardness, wear resistance and good heat resistance, but it is relatively expensive.
Ceramic material
Made of carbon fiber or graphite composite materials, it is lightweight, wear-resistant and has excellent heat resistance, but it is extremely expensive and is mostly used in high-performance sports cars.
Carbon fiber ceramic material
Made of carbon fiber composite materials, it is lighter in weight and has excellent heat dissipation performance, but it is expensive and is commonly found in high-end vehicle models.
Ordinary vehicles generally use gray cast iron brake discs, while high-performance or high-end models may choose alloy, ceramic or carbon fiber ceramic materials.
The main function of the rear brake disc in a car is to assist the front brake disc. Through friction, it helps the vehicle maintain stability and balance during braking and prevents the rear from swaying.
Specific functions
Youdaoplaceholder0 auxiliary braking force distribution
When a vehicle brakes, the front brake disc bears more than 70% of the braking force, while the rear brake disc mainly handles the remaining part, achieving deceleration or stopping through friction.
Youdaoplaceholder0 maintain vehicle balance
The rear brake disc can effectively suppress the rear swing of the vehicle and enhance driving stability under conditions such as emergency braking or slippery roads.
Youdaoplaceholder0 heat dissipation and wear resistance
The rear brake disc has relatively lower requirements for heat dissipation and wear resistance, but it needs to ensure basic friction performance to cooperate with the front disc to complete the braking task.
The damage to the rear brake disc of a car needs to be handled according to the specific situation:
Replace the brake disc
If the brake disc shows cracks, abnormal wear or insufficient thickness (below the manufacturer's standard), it needs to be replaced as a whole. The replacement steps include:
Lift the vehicle and remove the tires
Remove the brake calipers and take off the old brake discs
Reset the calipers after installing the new brake discs
Adjust the brake pedal to eliminate clearance
Repair the brake disc
Minor damages (such as scratches or local wear) can be ground smooth by a brake disc repair machine, but the following conditions must be met:
The damage did not exceed 50% of the board surface
No conical or grooved wear occurred
Emergency response measures
If the brakes fail:
Turn on the hazard warning lights and try to shift gears to slow down (gradually downshift for manual transmission and switch to a lower gear for automatic transmission)
For models without ABS, ABS braking can be simulated (deep press - release the pedal) to prevent lockup
Friction guardrail deceleration (only used when there are no other vehicles)
It is recommended to contact professional maintenance first to avoid potential safety hazards caused by self-disassembly and assembly.
The causes and solutions for fine marks on brake discs:
Only the front or only the rear brake discs have grooves. This situation is usually caused by driving habits and the frequent uneven distribution of braking force between the front and rear. Some people like to slam on the brakes when they step on them, which is a bit violent driving.
Solution: Correct driving habits and pay attention to the braking force. At the beginning, you should slowly and steadily press down the brake, maintain the force, and then adjust the force of applying the brake according to the actual changes.
What foreign object got stuck between the brake disc and the brake pad? At this time, it happened to be caused by braking hard.
Solution: Remove foreign objects.
It is caused by the unbalanced force of the brake caliper.
Solution: Inspect and repair.
Defects in the manufacturing process of brake pads result in uneven mixing of materials, causing the brake pads to be too hard or containing large metal particles inside.
Solution: Clean the metal particles.
It is caused by the long-term wear of brake discs and brake pads.
Solution: Replace the brake discs and brake pads when necessary.
If the fine marks on the brake disc are irregular, it might be caused by the vehicle's braking deviation.
Solution: Inspect the vehicle and carry out repairs.
If the brake discs of a vehicle show such phenomena, it is a normal occurrence and car owners need not worry too much. If the brake disc is not marked with fine lines but with grooves, it is an abnormal phenomenon. The brake disc needs to be replaced in time to ensure that the vehicle's braking function can be used normally. When using a vehicle, car owners should pay attention to the maintenance of brake discs. When the vehicle has traveled 60,000 to 80,000 kilometers, replace the brake discs on the front side of the vehicle. When the vehicle has traveled about 100,000 kilometers, replace the brake discs on the rear side.
The main body of brake pads is generally divided into two parts: the friction layer and the steel back (or backplate). What we see from the outside of the tire is the steel back. The steel back does not play a role in friction. Its main function is to facilitate installation in the brake caliper and enhance the strength of the brake pads. There is not much difference among different manufacturers of steel backs, and the technical content is not high. The main difference in the quality of brake pads lies in the friction layer. The friction layer is made of composite materials, which are uniformly mixed with organic fibers, inorganic fibers, mineral fillers, phenolic resin, etc., and formed by hot pressing in a high-temperature and high-pressure environment inside a press. Nowadays, many brake pads divide the friction layer into two layers of material: the base layer and the surface layer. The base layer is located between the steel back and the surface layer. During the use of brake pads, the surface layer material will wear out first, then the base layer material, and then the steel back. Generally, brake pads should be replaced before the surface layer material wears out completely.
If you want to know more, keep reading the other articles on this site!
Please call us if you need such products.
Zhuo Meng Shanghai Auto Co., Ltd. is committed to selling MG&MAXUS auto parts welcome to buy.
