The maintenance of a car chassis is often regarded as dispensable, far less important than the engine and body. In fact, whether the car chassis is properly maintained directly affects various key performances such as safety, handling, comfort, and economy. Therefore, it should not be taken lightly at all. The maintenance of a car chassis has many similarities with engine maintenance. It requires timely inspections in the following areas:
1. Timely check of the oil condition of important assemblies: This includes the transmission, braking system, power steering system, etc. On one hand, it is necessary to strictly follow the time regulations in the manual and go to authorized service stations for replenishment or replacement on a regular basis. On the other hand, you should also conduct self-checks and observations. Generally, you can check while refueling the car, ensuring that the oil level in each reservoir is between the upper and lower scale lines. If it falls below the lower scale line, it should be replenished promptly. If the oil level drops quickly, it indicates a system leak, which needs immediate inspection and repair. One crucial point to note is that the added oil must be of the same specification and grade as the original to avoid chemical reactions from mixing different oils, which could lead to oil deterioration.
2. Pay attention to the wear of brake pads and clutch plates and replace them in time. Both types of friction pads are consumables and will wear out after a period of use, losing their original function. Failing to replace them in time can easily cause accidents. Generally, cars have corresponding warning indicator lights that will issue warning signals in a timely manner, reminding users to replace them. In large buses, sometimes friction pads are riveted to steel backs with rivets. We may hear a sharp, piercing sound when the driver brakes, which is a warning that the friction pad has worn down to the rivet and must be replaced immediately. However, most modern cars now use adhesive methods to connect friction pads to steel backs. Only when the friction pads are worn down to the end and metal-to-metal contact occurs will a sound be produced. By this time, replacing the friction pads is already too late. Therefore, electronic signal sensors are installed, lighting up the brake warning light on the dashboard approximately when the friction pad is left with 1.5 millimeters, reminding the driver to replace the friction pads. As a side note, during rainy or humid weather, friction pads absorb moisture, significantly reducing friction. At this time, when starting the car, gently press the brakes and clutch a few times to evaporate the moisture on the friction pads using heat generated by friction before driving.
3. Four-wheel alignment is very important. At first glance, the four wheels of a car seem to stand upright on the ground. However, if measured with an instrument, it will be found that they deviate by an angle in the X, Y, and Z planes, though the values are small, generally only 0.5 to 2 degrees, indiscernible to the naked eye. Don't underestimate these three small deviation angles; they determine the car's steering performance. If a collision occurs or prolonged use causes changes due to wear, the handling ability will decrease significantly. Therefore, if you feel something unusual when operating the steering wheel, you should go to a formal auto repair shop or professional four-wheel alignment inspection station for inspection and make corresponding adjustments. The cost is not high but ensures safe driving. Cars often encounter rain and snow weather, and the chassis coming into contact with water can easily rust. If saltwater spraying is used to defrost snow, saltwater will accelerate corrosion of steel; driving on rough roads, the spinning wheels can also throw up stones that strike the chassis. Therefore, some manufacturers recommend spraying a protective film on the chassis to improve rust prevention capabilities, reduce impact damage, and extend the life of the chassis. However, this should be analyzed specifically. Nowadays, many medium and high-end sedans already use double-sided galvanized steel plates, and gaps where water might accumulate are treated with wax injection technology, generally lasting 10 to 15 years without issues. Some cars have rust-proof steel plates covering the bottom, preventing water ingress and reducing aerodynamic resistance. For such cars, additional measures are unnecessary.
4. Tire maintenance is key. A tire blowout at high speed can cause major accidents, ranging from tipping over and loss of control to complete rollovers. Even if no accident occurs, stopping by the roadside to change a tire is absolutely not a pleasant experience. Therefore, checking the condition of the tires before each trip is essential. First, check the tire pressure. Over-inflated tires are prone to blowouts, especially in summer, while under-inflated tires increase vehicle resistance and fuel consumption accordingly. Therefore, the specified pressures for front and rear tires differ, clearly marked in the car manual. For convenience, the information is also clearly labeled on the plaque next to the driver's seat door pillar. Of course, adjustments should also be made according to conditions. For example, on wet roads or hot weather, the pressure should be slightly lower.
Frequent checks on the tread surface of the tires are necessary. When driving on poor road conditions, regularly inspect the tread patterns for any sharp nails, stones, or broken glass that may puncture the tires. When the tread wears down to a certain extent, it is time to replace the tires. Typically, when the tread is worn down to only 1.5 to 2 millimeters, a specific mark will appear on the tire. Different brands of tires have different markers, but the details are provided in the manual. At this point, the tires need to be replaced.
According to the manufacturer's regulations, after driving a certain distance, the front and rear tires should be swapped. Because the load-bearing weights of the front and rear tires differ, so does the wear, swapping them can maximize utility and extend the lifespan of the tires. However, note that radial tires and bias-ply tires have different replacement methods. The former swaps straight front-to-back, while the latter uses a cross-eight swap method. Modern sedans mostly use tubeless tires, even if pierced by a nail, it is not a big problem as they have self-sealing functions. Tires with inner tubes, however, would immediately lose air. When using tubeless tires, the requirements for rims are higher. Steel rims produced by rolling do not meet the precision requirements, so aluminum alloy rims produced by machining are needed. However, aluminum alloy rims have low hardness and can be damaged during tire replacement if improper tools are used. It is best to choose a store with a dedicated tire removal and installation machine for tire replacement, and perform dynamic balancing on a dedicated tire balancer. Otherwise, vibrations will occur during driving. It must be noted that all four tires on the car should be of the same specifications, and ideally, the same brand. The sides of the tires are weak points and prone to abrasion. Therefore, when driving, be careful not to let the tires rub against curbs or other hard objects. Always carry a spare tire that is fully inflated. It is best to also carry a can of tire sealant in case of leaks for temporary fixes to get the car to a repair point. It is best to learn how to change tires yourself. In the trunk of the car, the manufacturer has already prepared a spare tire and the necessary tools for replacement, such as a jack and wrench. For men, changing a tire should not be a difficult task.