الكاوتش والفرامل كويسين.

Because Egyptian Arabic usually drops the verb to be in the present tense.

So:

الكاوتش والفرامل كويسين
literally looks like
the tires and the brakes good

but it naturally means:

The tires and the brakes are good.

This is very normal in Arabic. In past or future, a verb can appear, but in the present tense it is usually omitted.

Because both nouns are definite: the tires and the brakes.

In Arabic, when you join two definite nouns with و (and), each one normally keeps its own الـ:

• الكاوتش = the tires
• الفرامل = the brakes

So Arabic says:

الكاوتش والفرامل

not a structure like the tires and brakes with the article only once.

In Egyptian Arabic, كاوتش is a very common everyday word for tires/tyres.

It is often used collectively, so الكاوتش can mean the tires as a set, not just one tire.

If a speaker wants to be more specific about one tire, they may say something like فردة كاوتش.

So even though the form may look singular to an English learner, in context it often refers to the tires generally.

In everyday Egyptian, الفرامل is the normal word for the brakes or the braking system.

It is typically used this way as a set, just like English often says the brakes. So in this sentence, you should understand it as plural in meaning.

A learner does not need to force a neat one-word singular here. In normal speech, الفرامل is the standard car-related word people use.

Because الكاوتش والفرامل works as one combined subject: the tires and the brakes.

Arabic does not need to repeat the adjective after each noun if the same description applies to both. So:

الكاوتش والفرامل كويسين
= The tires and the brakes are good.

One predicate at the end can describe the whole joined subject.

كويس means good / okay / in good condition.

كويسين is the plural form used here. Since the sentence is talking about two things together—the tires and the brakes—a plural predicate is natural.

This is especially normal in Egyptian Arabic. If you are coming from formal Standard Arabic rules, some agreement patterns may look different, but كويسين here is very natural Egyptian speech.

Also:

• كويس = singular masculine
• كويسة = singular feminine
• كويسين = plural/default form
• كويسات is mainly for feminine human plural, so it would not fit here

Because كويسين here is a predicate, not an adjective directly attached to a noun.

Compare:

• الفرامل كويسة = The brakes are good
• الفرامل الكويسة = the good brakes

In the sentence you gave, كويسين means are good, so it does not take الـ.

If you added الـ, it would sound more like the good ones, not a normal present-tense statement.

A rough pronunciation is:

el-kawetch wel-farāmel kwayyisīn

A few helpful notes:

• الـ is usually pronounced el- or il- in Egyptian
• و (and) is usually pronounced we in speech, so والفرامل sounds like wel-farāmel
• كويسين is roughly kway-yi-SEEN

You do not need to pronounce it in a very formal Standard Arabic way; this sentence is clearly Egyptian colloquial.

Here it means something like:

• good
• okay
• in good condition
• working fine

With car parts, the meaning is practical, not moral and not really about beauty. So the sentence is saying that the tires and brakes are in good shape / functioning well.