The method of constructing leaf springs depends on the method of their attachment and construction. Spring bolts must be removed with special pullers, after the springs are completely relieved. Dismantling of the removed springs should be performed with particular care, when the spring leaves preload, working on the stirrups and the connecting bolt (astringent), are sometimes quite significant. For this reason, special grips should be used, ensuring work safety. After dismantling, the spring must be checked, that individual feathers are not excessively worn, or that they do not show surface cracks. Defective feathers are replaced with new ones. The spring is installed after its leaves are lubricated with a mixture of graphite and oil. The connecting bolt is usually replaced with a new one. As a rule, the spring bushings and pins are replaced with new ones, because they are usually excessively worn or show signs of seizure due to careless lubrication.