99 s70 t5 Spongey sound from front brake VIDEO

speedyt5 · Post by **speedyt5** » 03 Jul 2014, 20:56

It rained today, driving home, the left front brake made this noise, very spongey sounding, as I applied it it made the noise and as I took my foot of the brake it made a little bit of the same sound. Here is a video of it. I have never heard brakes make this noise before.

difflock54 · Post by **difflock54** » 04 Jul 2014, 17:56

Any brake fluid loss or visible leaks on the ground.
Check your brake hoses ASAP. Especially the front ones.

speedyt5 · Post by **speedyt5** » 07 Jul 2014, 21:42

thank you, i don't see any fluid loss. it really only did it after it rained and it was just the left front pad. so weird. maybe something got stuck in between pad and rotor? When I put the car in reverse and go slowly I can hear a squeaking every couple seconds which I'm guessing means part of the rotor might be warped.

speedyt5 · Post by **speedyt5** » 17 Jul 2014, 21:45

It rained today and the noise is back!

Post by **abscate** » 18 Jul 2014, 03:08

Disc brakes inherently make more noise than drum brakes in my experience, it just seems that the brake friction surface rides closer to the rotor than drums, so any corrosion, penguin feathers, or Swedish meatballs that get caught are going to scrape around. The advantage is mega better brake efficiency, self adjusting nature, and lack of fading of course

If your rotors aren't waffling and pulsating I doubt they are warped. A new set of pads might fix the noise.

speedyt5 · Post by **speedyt5** » 18 Jul 2014, 19:38

The pads are only a year old. It is just the front left one, and only when it gets wet? Any ideas? It makes the sound when I apply the brakes, but also when I let off of the brake as well.

Jazzop · Post by **Jazzop** » 18 Jul 2014, 20:20

I admit I only looked at this thread because I wondered what a sponge sounded like. What a synæsthetic choice of words! I would describe that sound as "graunchy", but that's just my own idiom and it probably makes no sense to anyone else.

Assuming you didn't boost that sound with software in order to make it more audible in the video, it seems loud enough to merit attention. I have no helpful ideas yet, but I'll ask some questions that should probably be answered for anyone to be able to help you out. Pardon ifsome of these questions seem silly or insulting to your intelligence-- it's nothing more than scientific rigor.

1. Are you sure the sound is coming from the wheel? If so, how many wheels is it coming from? You might need a helper to crouch down and listen to each wheel as you brake. I ask this because there is a definite hint of air passage in the sound, which suggests something is going on in the vacuum brake booster.

2. What is the illuminated warning light I see on your instrument cluster in the video? Is your system throwing a code? Have you seen the ABS or brake warning lamps illuminated recently? If not, have you verified that they work during the startup process when all warning lamps should illuminate briefly?

3. Is there any abnormal feel to the brakes when you depress the pedal? (e.g., lots of pedal travel, pulsation, vibration, grinding, inconsistent/variable firmness) Try a few consecutive hard stops from a decent speed.

4. Is there a difference in pedal travel and/or firmness when you first hit the brakes and then release the pedal and reapply the brakes? This would suggest air in the system or a master cylinder leak.

5. Does the ABS work? In a safe place, try an emergency stop with enough force that the ABS engages.

6. Drive for a few minutes, then turn the engine off. Pump the brake pedal until it is firm. Does it increase in resistance/firmness with each consecutive pump (no dirty jokes, please

)? Once you get the pedal to maximum firmness (after 2-4 pumps), keep your foot on the pedal and crank the engine. Does the pedal give way slightly (<0.5 inch)? Keep your foot on the pedal still. Is there any change in firmness or pedal travel after sitting for 20-40 seconds at idle?

speedyt5 · Post by **speedyt5** » 18 Jul 2014, 20:28

Jazzop wrote:I admit I only looked at this thread because I wondered what a sponge sounded like. What a synæsthetic choice of words! I would describe that sound as "graunchy", but that's just my own idiom and it probably makes no sense to anyone else.

Assuming you didn't boost that sound with software in order to make it more audible in the video, it seems loud enough to merit attention. I have no helpful ideas yet, but I'll ask some questions that should probably be answered for anyone to be able to help you out. Pardon ifsome of these questions seem silly or insulting to your intelligence-- it's nothing more than scientific rigor.

1. Are you sure the sound is coming from the wheel? If so, how many wheels is it coming from? You might need a helper to crouch down and listen to each wheel as you brake. I ask this because there is a definite hint of air passage in the sound, which suggests something is going on in the vacuum brake booster.

2. What is the illuminated warning light I see on your instrument cluster in the video? Is your system throwing a code? Have you seen the ABS or brake warning lamps illuminated recently? If not, have you verified that they work during the startup process when all warning lamps should illuminate briefly?

3. Is there any abnormal feel to the brakes when you depress the pedal? (e.g., lots of pedal travel, pulsation, vibration, grinding, inconsistent/variable firmness) Try a few consecutive hard stops from a decent speed.

4. Is there a difference in pedal travel and/or firmness when you first hit the brakes and then release the pedal and reapply the brakes? This would suggest air in the system or a master cylinder leak.

5. Does the ABS work? In a safe place, try an emergency stop with enough force that the ABS engages.

6. Drive for a few minutes, then turn the engine off. Pump the brake pedal until it is firm. Does it increase in resistance/firmness with each consecutive pump (no dirty jokes, please )? Once you get the pedal to maximum firmness (after 2-4 pumps), keep your foot on the pedal and crank the engine. Does the pedal give way slightly (<0.5 inch)? Keep your foot on the pedal still. Is there any change in firmness or pedal travel after sitting for 20-40 seconds at idle?

I am 95% sure it is coming from the front left wheel. However tomorrow I will have a friend check it out with me. Although it only seems to do it when it rains, so we may have to use the hose tomorrow. I do agree there may be some air passage. Good call on that I will check it out. The illuminated warning light was the srs, happened a while back due to passenger seat being replaced, but actually this week cleared everything and there are 0 warning lights on. There is no abnormal feel to the pedals, pretty much feel the same. I will have to check if there is a difference in pedal travel tomorrow when reapplying the brakes, however i have not noticed anything lately. As far as I know the abs works and I will try that tomorrow. I did pump the brakes tonight with the car on and everything seemed normal, but will try again tomorrow. Thank you for your help. Could water somehow be getting into the lines?

Jazzop · Post by **Jazzop** » 18 Jul 2014, 20:40

speedyt5 wrote:Could water somehow be getting into the lines?

Into the brake lines? You would notice this in a very significant way, very quickly.

I would be focusing on things external to the brake hydraulics, especially if there is no abnormal pedal feel or braking action.

whoa · Post by **whoa** » 18 Jul 2014, 20:58

Google around for "brake pedal creaking noise". Linkage to master cylinder is one culprit.