Disc brakes are fitted at all four wheels and include a brake pad warning system that monitors only one wheel per axle. It is important to check brake pad thickness whenever the wheels are off or brake work is being done. Brake pad wear can be assessed through an opening in the caliper by measuring the distance from the brake pad "ear" to the brake disc and comparing it to the specified minimum thickness of 3.0 mm (0.12 in). For a thorough inspection, unbolt the caliper from the steering arm to evaluate the brake pad thickness, brake disc, condition of the caliper seal, and condition of the caliper slider bolts. Additional techniques for checking brakes and procedures for replacing brake pads, discs, and calipers are also available.