A tapered pad will show a different thickness at one end of the pad and will cause uneven braking pressure and noise. This is usually caused by a distorted caliper, sticking caliper or excessive caliper clearance. The pads should be replaced and the caliper checked.

A pad that is unevenly worn across the surface is indicated by deep grooves. This will usually cause squeal and brake judder. The disc will also show corresponding grooves across the braking surface. If this problem occurs both the brake disc and pad should be replaced.

A denatured pad will show partially charred friction material evident by the white outer edges. This is caused by prolonged excessive temperatures, due to intensive use, dragging or faulty caliper.
This causes a reduction in the braking efficiency and the material becomes brittle and breaks up. If this occurs the pads must be replaced.

If the surface of the friction material becomes contaminated with oil, grease or brake fluid it can cause a vast reduction in braking performance on one side of the vehicle. This can cause the vehicle to pull to one side when braking. If this problem occurs the pads should be replaced immediately

A damaged pad is usually caused by excessive heat which causes the friction material to become brittle and begin to break up. If this problem occurs it is important to determine the cause of the excessive heat. This is usually a result of improperly balanced braking system, or a faulty caliper.

A glazed pad emits a reflective surface and can cause a reduction in the braking performance. This is usually due to excessive temperatures or excessive harsh braking during the bedding in period. If the performance is impaired then the pads must be replaced.

If one pad is more worn than its corresponding one then this is caused by one side of the caliper sticking. This will cause the brake to pull to one side and will accelerate pad wear to one side of  the set. If this problem occurs it is important to service the caliper and replace the pad set.

If small cracks appear in the brake pad, this is usually caused by incorrect flexing of the pad due to a sticking caliper. The piston bends the backplate causing the friction material to crack. If this occurs it is important to service the caliper and replace the pads.