Final answer:
Possible causes of a grinding noise when applying brakes include a) loose lining, b) glazed lining/drums, c) foreign material, and d) poor lining-to-drum contact.
Step-by-step explanation:
A cause of a grinding noise when the brakes are applied would include loose lining, brake block, or shoes; glazed lining and/or drums; foreign material embedded in friction material; and poor lining-to-drum contact.
Loose lining, brake block, or shoes can cause the noise due to their movement when the brakes are engaged. If the lining and/or drums become glazed, it can create a harsh grinding sound. Foreign material, such as debris or rust, embedded in the friction material can also contribute to the noise. Lastly, poor lining-to-drum contact can result in grinding sounds.