When selecting auto parts, you should pay attention to the following points:

1. Check whether the surface of auto parts is rusted

Qualified auto parts surface. It has both precision and bright finish. The more important auto parts. The higher the accuracy. The more strict the packaging is. Pay attention to inspection when purchasing. If rust spots are found on parts. Mildew spots or cracked rubber parts. Lose elasticity. Or there are obvious turning tool lines on the journal surface. It should be replaced.

2. See if the geometric dimension is deformed

Some auto parts are made because of. Transportation. Improper storage. Easy to deform. When checking. The shaft parts can be rolled along the glass plate for one circle. Check whether there is light leakage at the joint between the part and the glass plate to judge whether it is bent. When purchasing the clutch driven plate steel plate or friction plate. The steel sheet can be. Hold the friction plate in front of your eyes and observe whether it is warped. When purchasing oil seal. The end face of oil seal with framework shall be round. It can fit with flat glass without deflection and skeleton, and the outer edge of oil seal shall be correct. Deform it with your hand. It shall be able to return to the original state after releasing. When purchasing various gaskets. Attention should also be paid to checking the geometry and shape.

3. Check whether the protective surface is intact

Most auto parts are coated with protective coating at the factory. Such as piston pin. The bearing bush is protected with paraffin wax and the piston ring. The surface of cylinder liner shall be coated with antirust oil and wrapped with wrapping paper, and the valve. The piston is soaked in antirust oil and sealed with plastic bag. If the sealing sleeve is found damaged during purchase. The wrapping paper is missing. If the rust preventive oil or paraffin is lost, it shall be returned and replaced.

4. Check whether the assembly mark is clear

The assembly relationship of auto parts meets the technical requirements. Assembly marks are engraved on the surface of some parts (such as timing gear). If there is no mark or the mark is fuzzy, it cannot be recognized. It will bring great difficulties to assembly. Even wrong.

5. Check whether the joint is flat

Auto parts are moving. During storage. Due to vibration. Bump. Burrs often occur at the joint. Indentation. Broken or cracked. Affect the use of parts. Pay attention to inspection when purchasing.

6. Check whether the bonding parts are loose

A fitting composed of two or more parts. Parts are pressed together. Glued or welded. No looseness is allowed between them. For example, the oil pump plunger and the adjusting arm are assembled by press fitting, and the clutch driven shaft and the steel plate are riveted. The friction plate and steel plate are riveted or glued, the paper filter element framework and filter paper are glued, and the wire ends of electrical equipment are welded. If looseness is found during purchase. It should be replaced.

7. Check the mating surface for wear

If there are wear marks on the mating surface of auto parts. Or painted parts, old paint is found after removing the surface paint. Most of them are disguised as waste parts. At this time, you can ask for return and replacement.

8. Check whether the rotating parts are flexible

When purchasing rotating parts assembly such as oil pump. Rotate the pump shaft by hand. It should be flexible without jamming. When purchasing rolling bearings. Support the bearing inner ring with one hand. Turn the outer ring with the other hand. The outer ring shall be able to rotate freely. Then gradually stop. If the rotating parts do not rotate properly. Indicates internal corrosion or deformation. Don't buy.

9. Check the assembly components for missing parts

Normal assembly parts are intact. In order to assemble and operate smoothly. If individual small parts on some assembly parts are omitted. The assembly components will not work or even be scrapped.

10. See if the surface hardness meets the standard

The surface hardness of all mating parts has specified requirements. After confirming the purchase and negotiating with the merchant. The stubble of hacksaw blade can be used for trial cutting. There is no scratch when sliding. It indicates that the hardness is high, the hardness with slight marks after scratching is high, and there are obvious marks after scratching.

11. See if the logo is

The outer packaging quality of auto parts is good. The words on the packing box are clear. Overprint is bright in color. packing box. On the bag. The product name shall be marked. Specification and model. quantity Registered trademark. Factory name, address and telephone number, etc. Some manufacturers also make their own marks on auto parts. Some important components such as generator. Distributor. Fuel injection pump, etc. It is also equipped with operating instructions. Certificate and inspector seal. To guide users to use and maintain correctly. Carefully recognize when purchasing. In case you buy fake and shoddy products.