The Land Rover Disc Brake Pads are capable of creating friction against a metal surface without inflicting any damage to either component involved. This is made possible by the composite material of the disc brake pads which is designed to slowly turn to dust when stopping your Land Rover.
There are two disc brake pads on each front wheel assembly on your vehicle. They are pushed against the disc by the hydraulic pressure in the brake disc calipers. The caliper evenly squeezes the pads against the rotors so the friction can be created. As the Land Rover disc brake pads wear from being used, they slowly lose the composite material. As this occurs, the piston in the brake caliper moves out so the pads can remain next to the disc and properly function in their task of created the stopping power the driver of the Land Rover requires.
Because of the loss of material on the disc brake pads, the hydraulic fluid that was in the reservoir in the brake master cylinder is transferred to the caliper. This is why the fluid level in the master cylinder goes down. The larger rear reservoir is the one that supplies the front brake assemblies with hydraulic fluid. This is one of the methods an owner of a Land Rover can use to determine the amount of padding material that is left on their front dice brake pads. When logic suggests that more brake hydraulic fluid should be added to the master cylinder's reservoir, there is very little composite material left on the pads and a brake job should be performed on the vehicle. If this is not done then the solid metal backing plate the pads are mounted too will come in contact with the disc damaging both of them.