Taboo in construction machinery maintenance—piston open flame heating

When measuring the cylinder clearance, it is not possible to measure in the direction of the piston skirt perpendicular to the piston pin hole, but in other directions.

Since the piston and piston pin have an interference fit, when installing the piston pin, the piston should be heated and expanded first. At this time, some maintenance personnel will place the piston on an open flame to heat it directly. This approach is very wrong, because the thickness of each part of the piston is uneven, and the degree of thermal expansion and contraction will be different. Heating with an open flame will cause the piston to be heated unevenly and easily cause deformation; there will also be carbon ash attached to the surface of the piston, which will reduce the strength of the piston. service life.

If the piston cools naturally after reaching a certain temperature, its metallographic structure will be damaged and its wear resistance will be greatly reduced, and its service life will also be significantly shortened. When installing the piston pin, the piston can be evenly heated in hot oil to expand slowly. Do not use an open flame for direct heating.

There are many taboos in construction machinery maintenance. This is the third article in this series. We will continue to update it. If you are interested in it, you can pay attention to us. In addition, if you need to buy used excavators, used loaders, used graders and other used machinery or related accessories, you can contact us at any time.