Malaki ang pagkasira ng preno at gulong.

Filipino very often puts the predicate first. In this sentence, Malaki is the predicate, and ang pagkasira ng preno at gulong is the topic.

So the structure is basically:

• Malaki = is big / is extensive
• ang pagkasira ng preno at gulong = the damage to the brakes and tires

A more English-like order is also possible:

• Ang pagkasira ng preno at gulong ay malaki.

That version is more explicitly topic-first and can sound a bit more formal or emphatic.

Pagkasira is a noun meaning damage, breakage, or the state/result of being damaged.

It comes from the root sira, which can mean broken, damaged, or to break/damage depending on context.

Very roughly:

• sira = broken / damaged
• pagkasira = damage / deterioration / breaking

So pagkasira ng preno at gulong means damage to the brakes and tires.

Ang marks the topic of the sentence.

Here, the topic is:

• ang pagkasira ng preno at gulong

So the sentence is built like:

• Malaki = what is being said about the topic
• ang pagkasira ng preno at gulong = the topic being talked about

A helpful way to think of it is:

• As for the damage to the brakes and tires, it is extensive.

That is not a literal translation, but it shows the function of ang pretty well.

Here, ng links pagkasira to what is damaged.

So:

• pagkasira = damage
• ng preno at gulong = of the brakes and tires / to the brakes and tires

This ng often marks relationships that English expresses with of, to, or sometimes possession.

So:

• pagkasira ng preno = damage to the brakes
• pagkasira ng gulong = damage to the tires

In Filipino, malaki literally means big, but it is also commonly used to mean great, serious, or extensive in amount or degree.

So with something like damage, malaki means:

• large
• serious
• extensive

You would not normally use marami here, because marami is for things that are numerous or many in quantity, not for the severity or extent of damage.

So:

• Malaki ang pagkasira = The damage is extensive / serious
• Marami ang pagkasira would sound unnatural

Filipino nouns usually do not change form for singular vs. plural the way English nouns do.

So:

• preno can mean brake or brakes
• gulong can mean wheel, wheels, tire, or tires, depending on context

In real usage, context tells you whether singular or plural is intended. If the meaning shown to the learner is brakes and tires, that is perfectly normal.

If a speaker wants to make plurality clearer, they can add mga:

• mga preno at gulong = brakes and tires / the brakes and tires

But mga is not always necessary.

Gulong can refer to wheel and also often to tire, depending on context.

In vehicle-related everyday speech, people may use gulong in a broad practical way, and the intended meaning is usually clear from the situation.

So in a sentence about vehicle damage, gulong may be understood as:

• wheel
• tire
• sometimes the wheel/tire assembly in a loose everyday sense

Because malaki and ang pagkasira... are not forming a single adjective+noun phrase here. They are in a predicate-topic structure.

This sentence is:

• Malaki | ang pagkasira ng preno at gulong

But if you wanted to make big damage into one noun phrase, then you would use the linker:

• malaking pagkasira = big/extensive damage

Compare:

• Malaki ang pagkasira ng preno at gulong.
  = The damage to the brakes and tires is extensive.

• May malaking pagkasira sa preno at gulong.
  = There is extensive damage to the brakes and tires.

So the linker appears when the adjective directly modifies the noun inside one phrase.

Yes. That is grammatical and means essentially the same thing.

Compare the two:

• Malaki ang pagkasira ng preno at gulong.
• Ang pagkasira ng preno at gulong ay malaki.

The first is the very common predicate-first pattern in Filipino.
The second is also correct and may sound a bit more formal, explanatory, or emphatic depending on context.

Pagkasira is correct and natural, especially when talking about damage as a condition or extent.

But in everyday speech, speakers may also use simpler forms depending on the situation, such as:

• Malaki ang sira ng preno at gulong.

That can sound a bit more conversational.
Very roughly:

• sira = damage / defect / broken condition
• pagkasira = damage / the damaging or damaged state, often a bit more abstract or formal

So pagkasira is perfectly fine, but sira is also very common in casual speech.