1. Check whether the trademark logo is complete or the original brand trademark.
2. Check if there is any deformation in the geometric dimensions.
3. Check whether the joint is smooth.
4. Check if there is rust on the surface of the part.
5. Check whether the protective surface is intact.
6. Check if the glued parts are loose—fittings composed of two or more parts.
7. Check if the rotating parts are flexible.
8. Check if there are any missing parts in the assembly.
1. Check whether the trademark logo is complete or the original brand trademark. The outer packaging of the authentic product is of good quality, the handwriting on the box is clear, and the overprint colour is bright. Under normal circumstances, the original factory packaging boxes and bags should be marked with the product name, specification model, quantity, and a brand label. Some manufacturers also put their marks on the accessories. Some critical components, such as generators, distributors, fuel injection pumps, etc., are also equipped with instruction manuals, certificates of conformity and inspector stamps to guide users in the correct use and maintenance. When purchasing, you should carefully recognize it to prevent you from buying fake and shoddy products.
2. Check if there is any deformation in the geometric dimensions. Some parts are prone to deformation due to improper manufacturing, transportation, and storage. When inspecting, you can roll the shaft and other parts along the glass plate to see if there is light leakage at the joint of the part and the glass plate to judge whether it is bent. You can use the steel plate when choosing the clutch driven disc steel plate or friction plate. The friction plate is held in front of your eyes to observe whether it is warped; when purchasing an oil seal, the end face of the oil seal with a frame should be in a perfect circle, which can be fitted with the plate glass without bending. The outer edge of the non-frame oil seal should be straight and held. It deforms and should return to its original shape after letting go. When purchasing various gaskets, attention should also be paid to checking the geometric dimensions and shapes.
3. Check whether the joint is smooth. During the transportation and storage of spare parts, due to vibration and bumps, burrs, indentations, breakages or cracks are often generated at the joints, which affects the use of parts. Pay attention to inspection when purchasing.
4. Check if there is rust on the surface of the part. The surface of qualified parts has both a certain precision and a bright finish. The more important parts are, the higher the precision and the stricter the rust and corrosion protection of the packaging. Pay attention to inspection when purchasing. If the parts are found to have rust spots, mildew spots, or rubber parts cracked, lose elasticity, or there are clear-cutting tool lines on the surface of the journal, the ones that cannot be used should be replaced.
5. Check whether the protective surface is intact. Most parts are coated with a protective layer when they leave the factory. For example, the piston pin and bearing bush are protected with paraffin wax. The surface of the piston ring and cylinder liner is coated with anti-rust oil and wrapped with wrapping paper; the valve, piston, etc., are soaked in anti-rust oil and then packaged in a plastic bag. If the sealing sleeve is damaged, the packing paper is lost, the anti-rust oil or paraffin wax is lost during the purchase, and sometimes the parts are stored for a long time and cause rust, etc., they should be returned and replaced.
6. Check if the glued parts are loose—fittings composed of two or more parts. The parts are press-fitted, glued or welded. No looseness is allowed between them. For example, press-fitting the oil pump plunger and the adjusting arm are combined; The clutch is driven wheel, the steel plate is riveted, and the friction plate and the steel plate are riveted or glued. The frame of the paper filter element and the filter paper are glued together; the thread ends of the electrical equipment are welded. If any looseness is found during purchase, it should be replaced.
7. Check if the rotating parts are flexible. When purchasing a rotating part assembly such as an oil pump, turn the pump shaft by hand, and you should feel flexible and free from jamming;
When choosing a rolling bearing, support the inner ring of the bearing with one hand and rotate the outer ring with the other. The outer ring should rotate quickly and freely and then gradually stop. If the rotating parts do not rotate sufficiently, the inside is rusted or deformed, so don’t buy it.
8. Check if there are any missing parts in the assembly. The regular assembly parts must be complete and intact to ensure smooth assembly and regular operation. If the individual small parts on some assembly parts are missing, the assembly parts will not work or even be scrapped. Look at whether the assembly screws have been disassembled, etc. If any, there may be problems with some accessories or non-original parts.
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