There are many moving parts may produce noise

There are many moving parts may produce noise , and some may not rotate the rotation member and the contact member occurs . If the confirmation is four  tapered roller bearing  noise , may be damaged and need replacing.  2. Because the former leads to the failure of both sides working conditions are similar , so even just a bad one , it is recommended to replace in pairs . 3. Relatively sensitive to imports, in any case need to adopt the right approach and the right tools. In storage and during installation , the bearing parts can not be damaged. Require greater pressure pushed , so they need special tools. Be sure to refer to the manual . 4. Installation should be clean and tidy environment, will shorten bearings for printing machine  the tiny particles into the four -row cylindrical roller bearing life. Maintaining a clean environment when replacement is important. Allowed to tap with a hammer , be careful not to fall to the ground ( or similar misconduct ) . Before installation of the shaft and housing should also check condition , even a slight wear will lead to poor fit , thereby causing damage.  Metallurgical quality imported bearing materials was the main factor in the impact of early bearing failure .