שני הבלמים תקינים.

Because שני is the form used before a noun: שני הבלמים = the two brakes / both brakes.

שניים is usually used when two stands on its own, without a noun right after it.

• שני הבלמים = the two brakes
• שניים תקינים = two are working / two are fine

So in this sentence, שני is the correct form.

It can literally mean the two brakes, and in natural English that often becomes both brakes.

Because the noun is definite here (הבלמים = the brakes), the whole phrase is definite:

• שני בלמים = two brakes
• שני הבלמים = the two brakes / both brakes

So in this sentence, both brakes is a very natural translation.

In Hebrew, when you say the two..., the definiteness is usually marked on the noun, not on the number.

So:

• שני הבלמים = the two brakes
• not השני בלמים

This is normal Hebrew structure with numbers.

The singular is בלם = brake.

The plural is בלמים = brakes.

So:

• בלם = one brake
• בלמים = brakes
• הבלמים = the brakes

The ending -ים is the regular masculine plural ending.

You can tell from the plural ending -ים, which is the usual masculine plural ending, and also from the agreement in the sentence:

• שני is the masculine form for two
• תקינים is masculine plural

So all the parts match a masculine plural noun.

If the noun were feminine, you would expect forms like שתי and תקינות instead.

תקינים agrees with בלמים in gender and number.

Since בלמים is masculine plural, the adjective also has to be masculine plural:

• masculine singular: תקין
• feminine singular: תקינה
• masculine plural: תקינים
• feminine plural: תקינות

So שני הבלמים תקינים is grammatically matched all the way through.

Here תקינים means something like:

• in proper working order
• functioning properly
• not faulty
• serviceable

With something mechanical like brakes, תקינים is better understood as working properly rather than just correct.

So the sentence means that the brakes are not broken and are operating as they should.

There is no separate word for are in the present tense here. Hebrew often leaves out the present-tense verb to be.

So:

• שני הבלמים תקינים literally looks like
• the two brakes functioning-properly

But in natural English, you translate it as:

• Both brakes are working properly
• The two brakes are in good condition

This is a very common Hebrew pattern.

Yes. שני הבלמים תקינים is a normal and natural word order.

The structure is:

• שני הבלמים = the subject
• תקינים = the description/predicate

So it is basically:

• Both brakes
  • are functioning properly

Hebrew often uses this kind of straightforward subject + adjective structure in the present tense.

A simple pronunciation guide is:

shney ha-blamim t'kinim

More carefully:

• שני = shney
• הבלמים = ha-blamim
• תקינים = t'kinim

The stress is usually heard roughly like this:

• shNEI
• ha-blaMIM
• tkiNIM

Yes. הבלמים תקינים means the brakes are functioning properly.

Adding שני makes it more specific:

• הבלמים תקינים = the brakes are fine
• שני הבלמים תקינים = both brakes are fine / the two brakes are fine

So שני adds the idea of two or both.