Questions & Answers about Der Bremsbelag ist nicht neu.
Because Bremsbelag is a masculine noun in German, so its nominative singular article is der.
A useful rule with German compound nouns is that the last part decides the gender. Here the last part is Belag, and Belag is masculine, so the whole compound is masculine too:
- der Belag
- der Bremsbelag
So in this sentence, der is the correct article.
It is in the nominative case because it is the subject of the sentence.
You can identify the subject by asking: What is not new?
Answer: Der Bremsbelag.
So the structure is:
- Der Bremsbelag = subject, nominative
- ist = verb
- nicht neu = predicate description