Die Bremse hat einen neuen Bremsbelag.

Bremse is a feminine noun in German, so its basic dictionary form is die Bremse.

In this sentence, die Bremse is the subject, so it is in the nominative case:

• die Bremse = the brake

A learner might also wonder whether die could be plural. It can, but not here, because the verb is hat, which is singular. If it were plural, you would expect haben:

• Die Bremsen haben ... = The brakes have ...

Hat is the 3rd person singular present form of haben (to have).

The subject is die Bremse, which is singular, so the verb must also be singular:

• ich habe
• du hast
• er / sie / es hat
• wir haben
• ihr habt
• sie / Sie haben

So:

• Die Bremse hat ... = The brake has ...

Because Bremsbelag is the direct object of the sentence, and direct objects normally take the accusative case in German.

The noun Bremsbelag is masculine:

• der Bremsbelag = nominative
• einen Bremsbelag = accusative

So the article changes:

• ein → einen

And the adjective also changes:

• neu → neuen

That gives:

• einen neuen Bremsbelag

Compare:

• Ein neuer Bremsbelag ist teuer.
  Here it is the subject, so it is nominative.
• Die Bremse hat einen neuen Bremsbelag.
  Here it is the object, so it is accusative.

The adjective ending depends on:

1. the gender of the noun,
2. the case,
3. and what kind of article comes before it.

Here:

• Bremsbelag is masculine
• it is accusative
• it follows the indefinite article einen

After einen in masculine accusative, the adjective takes -en:

• einen neuen Bremsbelag

This is a very common pattern:

• einen guten Film
• einen alten Motor
• einen kleinen Fehler

Bremsbelag is a compound noun, which is very common in German.

It is made from:

• Brems- = brake / braking
• Belag = lining, coating, covering

So Bremsbelag is literally something like brake lining, which in context is usually brake pad.

A very important rule for German compounds:

• the last part determines the gender

Since Belag is masculine (der Belag), the whole compound is masculine:

• der Bremsbelag

Because all nouns are capitalized in German.

So:

• die Bremse
• der Bremsbelag
• das Auto
• ein Problem

This is one of the easiest ways to spot nouns in written German.

By itself, die could be either:

• feminine singular
• or plural

So die Bremse could look ambiguous at first glance. But the verb tells you what it is:

• Die Bremse hat ... → singular
• Die Bremsen haben ... → plural

So in your sentence, it definitely means the brake, not the brakes.

Normally, no. In standard German, a singular countable noun usually needs an article or some other determiner.

So the normal version is:

• Die Bremse hat einen neuen Bremsbelag.

Without the article, it sounds incomplete or nonstandard in most contexts.

German often requires a determiner where English may sometimes omit one more easily.

The sentence uses the normal neutral word order for a main clause:

• Die Bremse = subject
• hat = verb
• einen neuen Bremsbelag = object

So:

• Die Bremse hat einen neuen Bremsbelag.

German main clauses usually put the finite verb in second position. You can move other elements to the front for emphasis, but the verb still stays in second position:

• Einen neuen Bremsbelag hat die Bremse.

That version is grammatically possible, but it is less neutral and gives special emphasis to einen neuen Bremsbelag.

A simple way to identify them is:

• Ask who/what is doing the action?
  → die Bremse
  So that is the subject and therefore nominative.

• Ask what does the brake have?
  → einen neuen Bremsbelag
  So that is the direct object and therefore accusative.

So the structure is:

• Die Bremse = nominative feminine singular
• hat = 3rd person singular of haben
• einen neuen Bremsbelag = accusative masculine singular

The dictionary forms are:

• die Bremse = brake
• haben = to have
• der Bremsbelag = brake pad / brake lining
• neu = new

When you look words up, you usually want the noun with its article, because the article tells you the noun’s gender:

• die Bremse
• der Bremsbelag

That gender information is what lets you build forms like:

• die Bremse
• einen neuen Bremsbelag