1. New products are not selected
When replacing the cylinder liner and piston of a small steel wheel roller, the size grouping code of the standard cylinder liner and piston must be checked. The size grouping code of the cylinder liner and piston must be the same to ensure the standard fit clearance.
2. Inaccurate measurement of cylinder clearance
When measuring, it is stipulated that the gap in the direction of the long axis of the ellipse shall prevail, that is, the measuring piston skirt shall be measured perpendicular to the piston pin hole.
3. Open flame heating piston
The open flame directly heats the piston, the thickness of each part of the piston is uneven, and the degree of thermal expansion and cold contraction is different, which is easy to cause deformation. If it reaches a certain high temperature, the metal structure will be damaged after natural cooling, which will reduce the wear resistance and greatly shorten the service life.
4. Grinding the bearing bush with emery cloth
In order to increase the contact surface between the bearing and the shaft, many maintenance workers use emery cloth to polish the bearing. Because the sand is hard and the alloy is soft, the sand is easily embedded in the alloy during grinding, which will accelerate the wear of the bearing and shorten the service life of the crankshaft. .
5. Oil is only added but not changed
There are a lot of mechanical impurities in the used oil. Even if it is drained, there are still impurities in the oil pan and oil circuit.
6. Indiscriminate use of grease
When some road roller repairmen install the cylinder head gasket, they like to apply a layer of grease on the cylinder head gasket. The cylinder head gasket not only requires strict sealing of the high temperature and high pressure gas generated in the cylinder, but also seals the cylinder head and the cooling water with a certain pressure and flow rate in the cylinder body. When the cylinder head bolts are tightened, a part of the grease will be squeezed into the water channel and oil channel of the cylinder, and the lubricating grease left between the cylinder gaskets will easily flow from the high temperature and high pressure gas when the cylinder is working. Impact at the place, damage the cylinder head gasket, and cause air leakage. In addition, if the lubricating grease is in a high temperature state for a long time, it will produce carbon deposits, resulting in premature aging and deterioration of the cylinder pad.
7. The bolts are too tight
Excessive pre-tightening force will cause screws and bolts to break or thread slippage.
8. Tire pressure is too high
Too high or too low tire pressure will affect its service life, and it is also not conducive to safe driving.
9. The water tank "boils" and suddenly adds cold water
Sudden addition of cold water will cause the cylinder head and cylinder block to "burst" due to excessive temperature difference. Therefore, once the water tank is found to be "boiling" during use, emergency measures should be taken to ensure that the engine cooling water cools down by itself.
