Brakes Farting at Low Speed

[PotatoExplorer]

Weird thread title, I know. Not really sure how else to describe it but here goes! When I'm braking at very slow speeds, like the few feet before the vehicle comes to a complete stop, or when you are already at a complete stop and decide to move a few feet forwards or backwards (Like when you want to make sure you're fully in a parking spot or if you're parallel parking), the brakes seem to make a farting noise that's more along the lines of a shuddering or vibration. It's almost like dragging a wooden table or chair across the ground very slowly but the vibration is very noticeable in the brake pedal and steering wheel. I tried searching around the forums and internet to see if anyone else had anything similar and only found this thread on a Volkswagen Passat forum. Seems spot on with my problem but the thread just dies.

http://www.passatworld.com/forums/v...strange-sound-while-braking-any-thoughts.html

Anyone run into anything similar to this? I feel as if it might be coming from the rear brakes so I was planning on eventually pulling the rear wheels and getting a closer look at the rear braking system. Peering through the spokes don't reveal much. If anyone has an idea where to start digging into, that would be much appreciated!!!

 

[thebrakeman]

In the braking industry, it's called "creep groan". At very light pressure, enough to allow the vehicle to "creep" forward, the pads are still engaging the rotors, and oscillating back and forth between sticking and slipping...stick/slip/stick/slip, making a groaning sound.

It's a phenomenon that happens with some brake systems, and is very hard to design against. There are tradeoffs to every design and component decision. It's likely that changing to a different type of friction would make it go away. That is, if you are using ceramic, try a semi-metallic. Or if using semi-metallic, try a ceramic.

If you recently changed pads (or something else) and this noise started, consider going back to the type you had before. If this just started out of the blue, with no pad or other items replaced, it could simply be time for a brake job. Either way, this is not a cause for concern, as if something is broken, or is about to break. It's just an annoyance. It's up to you whether to do anything about it. Personally it does not bother me when one of my vehicles gets this. I simply learn what not to do. Or, when I want to make the kids laugh, I know what to do. Make the brakes fart, and blame it on one of them.

 

[D Hook]

Would glazing on the drum or rotors cause this?

 

[nathan mayden]

I recently installed Wagner thermo quiets and they do this real bad at low speeds.

 

[PotatoExplorer]

In the braking industry, it's called "creep groan". At very light pressure, enough to allow the vehicle to "creep" forward, the pads are still engaging the rotors, and oscillating back and forth between sticking and slipping...stick/slip/stick/slip, making a groaning sound.

It's a phenomenon that happens with some brake systems, and is very hard to design against. There are tradeoffs to every design and component decision. It's likely that changing to a different type of friction would make it go away. That is, if you are using ceramic, try a semi-metallic. Or if using semi-metallic, try a ceramic.

If you recently changed pads (or something else) and this noise started, consider going back to the type you had before. If this just started out of the blue, with no pad or other items replaced, it could simply be time for a brake job. Either way, this is not a cause for concern, as if something is broken, or is about to break. It's just an annoyance. It's up to you whether to do anything about it. Personally it does not bother me when one of my vehicles gets this. I simply learn what not to do. Or, when I want to make the kids laugh, I know what to do. Make the brakes fart, and blame it on one of them.

Wow, thanks! That's the first time I've ever heard of this and this is the first vehicle I've ever encountered this situation. I'm pretty sure this has happened since purchasing the vehicle since I haven't done anything to the brakes yet. The creep groan (or brake farting ) didn't really annoy me enough to start looking into it until recently. It's good to know that it's nothing to be concerned about. When I get time (hopefully this weekend or the next) I"ll be able to pull the rear wheels off to take a closer look. I want to check/test some steering components anyways. Suspension and brakes are my next area of focus on the Explorer.

Thanks TheBrakeMan!!

 

[07EddyB]

I recently installed Wagner thermo quiets and they do this real bad at low speeds.

I'm running those on my Ex front and rear and have never had that problem. Many variables at play here.

 

[Mbrooks420]

I would suggest taking the brakes apart, cleaning and greasing the slide pins, and pad mounts and see if it changes.

 

[thebrakeman]

......Many variables at play here.

Exactly

 

[tripplec]

I don't believe Wagner are as good as they used to. Made in China and very expensive pads to boot. I don't use them for a long time.