It is the part of the cylinder that is connected to the barrel section in the hydraulic cylinder and acts as a bed and contains sealing materials. The cap, also called the front cover, has assumed the throat function in the cylinder.
Since it will be in connection with the rod when connecting to the cylinder sleeve, improper production and connection will adversely affect the entire hydraulic system, especially the hydraulic cylinder. Again, if there is a mismatch in the throat with respect to the shaft axis, the piston may slip due to the pressure and deformation may occur in the rod, sealing and other parts of the bearing. The materials to be used for the bearing section of the cylinder should not come into contact with the cap (front cover).