The minimum thickness of the pads must be 7 mm, taking into account the carrier plate.
The actual carrier plate - that is, the piece of metal to which the overlay is glued - is about 5 mm thick. Thus, the overlay itself is about 2 mm.
When performing a quick check, it is enough to shine a lamp through the hole in the wheel with the cap removed and assess the thickness of the lining.
Brake fluid reservoir (2) with lid (1) and fill level marks (3).
Measuring the thickness of the brake pads of the front wheels. Minimum thickness of disc brake pads (without carrier plate) should be approximately 2 mm. If the pads are worn out, they must be replaced.
More precise control is carried out with the wheel removed.
Place a ruler on the pad and measure. Don't forget to inspect the friction lining on the inside!