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Discussion Starter #1
Hello, everyone.

A few months ago my B5.5 Passat when braking makes a weird "farting" sound, accompanied by the vibration of brake pedal. If I was describing the issue to the British Queen, perhaps, I'd say that the noise sounds like "U-R-R-P". But upon a thorough discussion with a friend of mine we agreed the "farting" is the closest, though not the most polite way to describe it :)

Initially we thought that the noise is caused by the air in the braking system. Since then the braking system was flushed 4 times. Indeed, there was a lot of air in the system. But the only thing coming out during the last two bleedings was a brake fluid. The order of bleeding/flushing was RR-LR-RF-LF. Nevertheless the sound is still there. :cry:

The sound/noise appears only at the final stage of braking process, i.e. when the car is just about to stop. It never showed up while braking at higher speed and doesn't depend on the speed of the car at which I start braking. Sometimes it shows up when I slightly release the brake pedal, for example to move a car a few feet forward in a traffic jam / on a traffic light.
I couldn't find any correlation with the outdoor temperature or intensity of the brake pedal pumping. It seems to me that the sound is coming from the front, however I wouldn't insist on that.

I clearly remember that the whole thing started right after the front CV shafts/joints were changed. I found a few threads here, stating that bad CV joints or poor contact of ABS sensor can account for this. However, the car doesn't show any ABS system error lights/codes. Old leaking CV joints were noisy during turns, not when stopping. Is there any way to discriminate between the possible causes?

Any thoughts/advice on this issue will be highly appreciated. :bowdown: It's really frustrating when my 21-st century made car sounds like a 19-th century mailcoach, and I seem not to be able to fix this. :banghead:
 

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Discussion Starter #3
Definitely not a click sound. And it's not coming from the area around my feet. Thanks for the advice, anyway.
 

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Does this sound occur during low or high-speed braking? Due to brake bias, I would check the condition of your front calipers and rotors. Are pads connecting to the rotor evenly??
 

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Discussion Starter #5
This sound occurs at low speeds only. Like I told, just prior to complete stop. And it doesn't happen every time. Sometimes the car brakes silently, and sometimes "farts" at the very last moment. The suggestion with calipers/rotors seems quite reasonable. Thanks.
 

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Hmmm... maybe your ABS sensors are "twitchy" and unreliable at low speeds, triggering ABS actuation? Actuate your ABS on purpose, and see if it makes the same sound.
 

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Discussion Starter #7
sirwired, looks like you've hit the point! I disassembled the ABS harness under the hood and my braking noise disappeared (of course I got ABS/brake light coming on). Now I'll ask my mechanic to check the front ABS sensors (distance from rotors and dirt) and rotors (dirt). I'll let you know after the check is performed.
 

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Discussion Starter #8
A few updates on this long playing issue. My mechanic checked the gap between the ABS sensors and rotors, didn't like what he saw and decided to order and replace CV joints once again. As it was at no charge for me, I presume his decision was objective and justified. Anyway this maneuver didn't help much. He also told me that he ensured that sensors went all the way into their position and cleaned the rotors to the best of his ability.
Now that I know that the issue is ABS related, my idea is to buy a new ABS sensor (or a proven working used one), put it on the right front side and check if the sound disappears. If it does - the problem is solved, if it doesn't - I'll try the left wheel.
However I still wonder if there is anything apart from the faulty ABS sensor itself in the ABS system that could cause this sound? Perhaps, I should start with something else.
Again, any comments are appreciated.
 

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I am also facing same issue with my passat. I just changed new tyres and its making fart noises when i brake completely and when i slightly released the brake pedal. What should I do with this?
 

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In my experience, the sound is from the pads either due to the makeup of the material, or contamination. Did you change pads recently?
 

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Yes i recently bought this and the dealer told me that he put the new pads.
VERY VERY likely then. Me being cheap, I had a couple of pad changes that resulted in that sound/feel and just either dealt with it, or tried to avoid the situations that made the noise.

Since this is a piggy back to an old thread, I will move these new posts to a new thread if the cause turns out not to be related to the original post.
 

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I have the same problem but I havnt touched the brakes at all all I have done is renew the whole front suspension
 

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You need to pull the ABS sensors and clean them. You loosened up rust in the hub while changing the front arms. It's pretty common.
 
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