1、 Check whether the trademark is complete. The external packaging of authentic products is of good quality, with clear handwriting and bright overprint color on the packaging box. The packaging box and bag shall be marked with the product name, specification, model, quantity, registered trademark, factory name and address, telephone number, etc. Some manufacturers also make their own marks on the accessories. Some important components, such as generator, distributor, fuel injection pump, etc., are also equipped with operation manual, certificate of conformity and inspector's seal to guide users to use and maintain correctly. You should be careful when choosing to avoid buying fake and shoddy products.
2、 Check the geometric dimensions for deformation. Some parts are easily deformed due to improper manufacturing, transportation and storage. During the inspection, the shaft parts can be rolled along the glass plate for a circle to see if there is light leakage at the joint between the parts and the glass plate to judge whether they are bent; When purchasing the steel plate or friction plate of the clutch driven plate, hold the steel plate and friction plate in front of your eyes to see if they are warped; When purchasing oil seal, the end face of oil seal with framework shall be round and can fit with flat glass without deflection; The outer edge of the frameless oil seal shall be straight, and it shall be deformed by holding it, and it shall be able to return to its original state after releasing it. When purchasing various gaskets, the geometric dimensions and shapes should also be checked.
3、 Check whether the joint is flat. During the handling and storage of spare parts, due to vibration and collision, burrs, indentation, damage or cracks often occur at the joint, affecting the use of parts. Pay attention to inspection when purchasing.
4、 Check whether the surface of parts is rusted. The surface of qualified spare parts has both a certain precision and a shiny finish. The more important the spare parts are, the higher the precision is, and the more strict the anti rust and anti-corrosion packaging is. When purchasing, pay attention to inspection. If parts are found to have rust spots, mildew spots or rubber parts are cracked or lose elasticity, or the journal surface has obvious turning tool lines, they should be replaced.
5、 Check whether the protective surface is intact. Most parts are coated with protective coating when leaving the factory. For example, the piston pin and bearing bush shall be protected with paraffin; The surface of piston ring and cylinder liner shall be coated with antirust oil and wrapped with wrapping paper; Valves, pistons, etc. shall be sealed with plastic bags after being immersed in antirust oil. If the seal sleeve is damaged, the packaging paper is lost, and the rust preventative oil or paraffin is lost during purchase, it should be returned and replaced.
6、 Check whether the bonding parts are loose. For the accessories composed of two or more parts, the parts are pressed, glued or welded, and no looseness is allowed between them. For example, the oil pump plunger and the adjusting arm are assembled by pressing; The clutch driven wheel is riveted to the steel plate, and the friction plate is riveted or glued to the steel plate; The paper filter element skeleton is glued to the filter paper; The wire ends of electrical equipment are welded. If any looseness is found during purchase, it shall be replaced.
7、 Check whether the rotating parts are flexible. When purchasing the rotating parts assembly such as oil pump, rotate the pump shaft by hand, and it should be flexible without clamping; When purchasing rolling bearings, support the inner ring of the bearing with one hand and rotate the outer ring with the other. The outer ring should be able to rotate quickly and freely, and then stop rotating gradually. If the rotating parts do not rotate properly, it indicates that the internal parts are rusted or deformed. Do not buy them.
8、 Look for missing parts in the assembly. Normal assembly components must be complete and intact to ensure smooth assembly and normal operation. If individual small parts on some assembly components are not installed, the assembly components will not work or even be scrapped.
