The ability to transform hydraulic pressure into mechanical movement is the task of the Nissan disc brake caliper. The movement is what forces the pads against the rotors which cause the friction to stop the wheels they are attached to. The life expectancy of the disc brake caliper is many years on a Nissan. The only non-metal component in them is the seal around the piston which contains the hydraulic fluid. When this seal cracks, fluid leaks out and can be noticed on the pavement below the wheel assembly. The driver will also notice the failing of the Nissan disc brake caliper by the change in the way the brake pedal feels. It will have to travel farther than before to obtain the same braking force. It also might appear to be softer. When a disc brake caliper does fails and begins to leak on your Nissan, the owner has a limited allotment of time before brake failure is imamate. As brake fluid leaves this otherwise closed loop system, air will eventual replace it. Air is not a medium that can be used in replacement of hydraulic fluid so the amount of friction the braking system on your Nissan will be able to produce will diminish to the point none will eventually exist. The replacement of the disc brake caliper only requires the removal of the brake hose and two hold down bolts. The most difficult part is the removal of the air that has become trapped in this closed loop hydraulic system once the hose is secured on the new component. With the new disc brake caliper in place on the wheel assembly, pressure has to be applied to the brake system by the depression of the brake pedal. When this is happening, the bleeder screw on the top of the caliper is opened and the air is allowed to escape. Now your Nissan is read for the road.