Fren kolu sıkılınca fren balatası hareket etti.

Here -ınca makes a time clause. It usually means when, once, or upon doing something.

So sıkılınca means something like:

• when it is squeezed
• once it is squeezed
• upon being squeezed

In this sentence, Fren kolu sıkılınca gives the time or trigger for the main action in fren balatası hareket etti.

Because sıkıl- is the passive form of sıkmak.

• sıkmak = to squeeze, tighten, press
• sıkılmak = to be squeezed, to be pressed

The brake lever is not doing the squeezing; it is receiving the action. So Turkish uses the passive-looking form:

• fren kolu sıkılınca = when the brake lever was squeezed

If you said sıkınca, that would more naturally mean when someone/it squeezed something, not when it was squeezed.

Not exactly. Sıkılınca is a converb (an adverbial verb form), not a full finite verb.

It does not stand alone the way was squeezed does in English. Instead, it connects one action to another:

• Fren kolu sıkılınca = when the brake lever was squeezed
• fren balatası hareket etti = the brake pad moved

So Turkish often uses one non-finite verb form plus one fully conjugated main verb, where English might use two full clauses.

Because these are noun compounds, which are very common in Turkish.

• fren kolu = brake lever
• fren balatası = brake pad

In this pattern, the first noun stays bare, and the second noun takes a possessive-type ending:

• kol → kolu
• balata → balatası

This does not necessarily mean actual possession in the ordinary English sense. It is just the normal way Turkish builds many compound nouns, especially technical ones.

That is because of the buffer consonant -s-.

When the compound ending is added:

• after a consonant, you can attach it directly
  
  • kol → kolu
• after a vowel, Turkish often inserts -s- to make pronunciation easier
  
  • balata → balatası

So:

• fren kolu
• fren balatası

The -s- is not a separate meaning by itself here; it is just a linking sound.

Because fren kolu is a standard compound noun meaning brake lever as a type of object.

Compare:

• fren kolu = brake lever
• frenin kolu = the lever of the brake

The second version sounds more like a specific possessive relationship. In technical vocabulary, Turkish usually prefers the compound form:

• araba kapısı = car door
• su şişesi = water bottle
• fren kolu = brake lever

So fren kolu is the natural form here.

Because hareket etmek is a compound verb:

• hareket = movement
• etmek = to do / to make

Together, hareket etmek means to move.

In the sentence:

• hareket etti = moved

Turkish has many verbs of this type:

• yardım etmek = to help
• fark etmek = to notice
• hareket etmek = to move

So it stays as two words, even when conjugated.

It is the simple past.

• etti = did / made in past form
• so hareket etti = moved

This tells you the main event happened in the past. The earlier part, sıkılınca, sets the condition or timing for that event.

Because -ınca usually marks a triggered event or a point in time: when/once X happens.

• sıkılınca = when it is squeezed / once it is squeezed

By contrast, -ken usually means while or during the time that.

So:

• fren kolu sıkılınca = when the brake lever is squeezed, then something happens
• fren kolu sıkılırken = while the brake lever is being squeezed

In this sentence, the idea is that squeezing the lever causes the pad to move, so -ınca fits better.

Yes. Fren kolu sıkıldığında is also possible and means roughly the same thing: when the brake lever is/was squeezed.

A rough comparison:

• sıkılınca = often a bit more direct, event-triggered, sometimes more conversational
• sıkıldığında = often a bit more neutral, formal, or explicit

Both are correct in many contexts. In short technical or explanatory sentences, sıkılınca sounds very natural.

It has two parts:

1. Fren kolu sıkılınca
   an adverbial time/trigger clause
   = when the brake lever was squeezed

2. fren balatası hareket etti
   the main clause
   = the brake pad moved

So the full structure is:

[When X happened], [Y happened].

This is a very common Turkish pattern:

• subordinate clause first
• main clause second

It can be changed, but the version you have is very natural.

Standard order here is:

• Fren kolu sıkılınca fren balatası hareket etti.

You could also say:

• Fren balatası, fren kolu sıkılınca hareket etti.

That puts more focus on fren balatası. But the original sentence is smoother and more neutral, especially in explanation or description.

The Turkish ı is one of the trickiest sounds for English speakers. It is:

• not ee
• not ih
• not uh
• a back, unrounded vowel

You can think of it as a sound somewhat like the vowel in the second syllable of roses for some speakers, but that is only approximate.

In this sentence:

• sıkılınca
• balatası

both contain ı, and pronouncing it clearly will make your Turkish sound much more natural. It is a separate vowel from i, so:

• i and ı are different sounds
• Turkish speakers hear them as completely different vowels