# Air sound from brake pedal



## LiveTrash (May 24, 2015)

zorro128 said:


> Hi to all. This is my first post here and I hope you can help me.
> 
> I am owner of chevy cruze ls, 1.6, 113hp, 90 000 km.
> 
> ...


You only hear it BEFORE you start the car? That's a normal sound (at least in my experience) when a brake pedal is pressed when the car is not running. I don't think it's air, but rather the hydraulic fluid building up pressure. I've noticed it in every car I've owned.


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## zorro128 (Sep 3, 2016)

Once I start the car I do not hear air in pedal and brakes work fine. I just push brake pedal few times and everything is fine

But, before pads replacement I did not hear air in pedal. Because of that I am worried.

My friend told me that maybe brake pads are no good, meaning not original spare parts. My retailer sent me brake pads for Opel Astra.

I am situated in Europe, by the way.


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## ChevyGuy (Dec 13, 2014)

I can't speak to the European version of the Cruze, but for the US, the brakes are power-assist via a vacuum. So I don't think a soft air noise is unusual. However, if it's become louder, it may indicate that the brake booster has a hole in it and is starting to fail. With the car off, how many times can you press the brake before the pedal gets hard? It should be 2-3 times. If less than that, you probably have a vacuum leak.


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## zorro128 (Sep 3, 2016)

Well, car was imported from Canada. I found out using VIN number.

I press brake pedal at least 3 times and afterwards brake is hard and fine.

Before pad replacement brake pedal was always solid and hard and there was no air leaking from pedal.

During brake pad replacement brake system was not touched but since I heard air coming out my mechanic bleeded fluid from brake system several times. Clutch and brakes use same fluid container.

As I said, prior to brake pad replacement I have change main clutch cylinder and brake pedal worked fine afterwards. 

Is it possible that I need to bleed fluid from this system too (Clutch is working fine)

One notice: I do not know if my mechanic used original spare part. Retailer sent him brake pads for Opel Astra.


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## ChevyGuy (Dec 13, 2014)

zorro128 said:


> I press brake pedal at least 3 times and afterwards brake is hard and fine.
> 
> Before pad replacement brake pedal was always solid and hard and there was no air leaking from pedal.


I'm staring to wonder if you've been driving without power assist and the mechanic noticed it was broken and fixed it without telling you.

How is the stopping power? If it greatly increased, then I think my theory is correct.


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## zorro128 (Sep 3, 2016)

My mechanic did not mentioned this. As far as I know he only replaced pads.

Stopping power is same as before. I had to change pads because I heard a squeak noise in rear brakes. Old pads were not changed since car was bought.

Past few days I read that this issue sometimes is caused because new pads need time to fit rotors.

Also maybe I should drain all fluid from brakes system and fill new one just to be sure there is no air. But I have bleed system several times.

Also people said perhapse new pads are not good quality.


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## zorro128 (Sep 3, 2016)

Today I had to press break pedal several times (more than 5) in order to get it hard.


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