MAINTENANCE
BRAKES
The five most important characteristics that are considered when selecting a brake pad material are as follows:
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The material's ability to resist brake fade
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The effects of water on brake fade (all brakes are designed to withstand at least temporary exposure to water)
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The ability to recover quickly from either increased temperature or moisture
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Service life as traded off with wear to the rotor
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The ability of the material to provide smooth and even contact with the rotor or drum (instead of a material that breaks off in chunks or causes pits or dents).[2]
For many years straightforward asbestos was viewed as having an optimal performance in all five categories. However, as the serious health-related hazards of asbestos became apparent, other materials had to be found. Today, brake pad materials are classified into one of four principal categories, as follows:
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Non-metallic materials - these are made from a combination of various synthetic substances bonded into a composite, principally in the form of cellulose, aramid, PAN, and sintered glass. They are gentle on rotors, but produce a fair amount of dust, thus having a short service life.
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Semi-metallic materials - synthetics mixed with varying proportions of flaked metals. These are harder than non-metallic pads, more fade-resistant and longer lasting, but at the cost of increased wear to the rotor/drum which then must be replaced sooner. They also require more actuating force than non-metallic pads in order to generate braking torque.
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Fully metallic materials - these pads are used only in racing vehicles, and are composed of sintered steel without any synthetic additives. They are very long-lasting, but require more force to slow a vehicle while wearing off the rotors faster. They also tend to be very loud.
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Ceramic materials - Composed of clay and porcelain bonded to copper flakes and filaments, these are a good compromise between the durability of the metal pads, grip and fade resistance of the synthetic variety. Their principal drawback, however, is that unlike the previous three types, despite the presence of the copper (which has a high thermal conductivity), ceramic pads generally do not dissipate heat well, which can eventually cause the pads or other components of the braking system to warp.[2] However, because the ceramic materials causes the braking sound to be elevated beyond that of human hearing, they are exceptionally quiet.
CAR SERVICE
A motor vehicle service or tune-up is a series of maintenance procedures carried out at a set time interval or after the vehicle has travelled a certain distance. The service intervals are specified by the vehicle manufacturer in a service schedule and some modern cars display the due date for the next service electronically on the instrument panel. A tune-up should not be confused with engine tuning, which is the modifying of an engine to perform better than the original specification, rather than using maintenance to keep the engine running as it should.
The completed services are usually recorded in a service book which is rubber-stamped by the service centre upon completion of each service. A complete service history usually adds to the resale value of a vehicle.
WHEELS & SUSPENSION
Suspension is the system of tires, tire air, springs, shock absorbers and linkages that connects a vehicle to its wheels and allows relative motion between the two.[1] Suspension systems must support both roadholding/handling and ride quality,[2] which are at odds with each other. The tuning of suspensions involves finding the right compromise. It is important for the suspension to keep the road wheel in contact with the road surface as much as possible, because all the road or ground forces acting on the vehicle do so through the contact patches of the tires. The suspension also protects the vehicle itself and any cargo or luggage from damage and wear. The design of front and rear suspension of a car may be different.