External inspection of the brake pads can be carried out with the brake drums or discs removed. The wear limit is reached when the brake pad thickness at its narrowest point is 1.5 mm.
When the wear limit is reached, replace the brake pads. Be sure to replace all the pads on the same axle at once.
Clean the brake drum and brake shield with a brake cleaner.
Check for damage and cracking of the anthers of the wheel brake cylinders.