jbgilbank

I have around 15,000 miles on the all new brakes and summer Pirelli's, so we shall see how many miles I'll actually get. I have read many stories about low mileage for all on these vehicles.
I finally understand why a Q7 would go through brakes quicker than normal vehicles other than the 5500 lbs that it weighs of course, Hill Hold Control (HHC) and Hill Decent.
Ever since I towed my trailer, my brakes squeal when I stop and they also squeal about 5 revolutions of the tires.
There is no squealing while driving normal or in rain as I remember, but when they are dry, they are super loud and embarrassing like a bus.
This is not something I would expect from an expensive luxury vehicle.

How do I solve this issue?

cuatrokoop

Get different brake pads. The squealing is due to the pad compound after it has been fully bedded and heated up sufficiently. More metal in the compound, more squealing.

dreadlocks

you given your wheels a good power cleaning lately? My brakes get noisy when they are dirty, all that break dust gunks stuff up... a good cleaning and they are nice and quiet again, but only for a couple weeks before the dust is bad enough again.

jbgilbank

Ahhhh, I have been cleaning with Sonax, which I highly recommend, every couple of weeks this summer!
Spray and wait about five minutes until it turns pinkish purple, rinse and brush quickly with soft brush and dish soap, then go through car wash.
I think it may have something to do with when I overheated them in the mountains.
I don't want to replace them so early, but man these suckers drive my wife nuts enough to bitch about them constantly, then it turns into the ride quality and etc. You know how it goes!
I'm about to squirt WD in there! haha!
Wondering if I could spray the back of the pads with that rubberized stuff? I know I have had to place that on new pads when replacing on all other vehicles. What are your thoughts on this?

dreadlocks

hrmm, take one of your front wheels off (the side that makes most noise) and take a good hard look at rotors.. any noticeable lip on em where the pads end? all new brakes, if that looks good.. put some lug bolts back in and spin the axle by hand as fast as you can.. have someone in car lightly press brakes and listen for a pulsing noise where its rubbing and not rubbing and rubbing (shht, shht, shht, etc) that usually indicates warped rotor and you need all new brakes.. if your rotors look good and not gouged out, discolored, etc put the wheels back on and go do some agressive brake bedding procedures in, where you get the brakes really hot and resurface em.. like 60-5-60-5-60-5mph hard and then let em cool down naturally driving a bit more, might take a few times if you really glazed the pads up, might try braking hard in reverse once when you got em hot.. its not really a science but the idea is to wear past your current squeaky surface fast and leave it with a better surface.. If they still squeal, go buy all new pads and give em an agressive bedding procedure as well.. the brembo calipers we have let you hotswap your pads out in a few moments.

After your towing adventure I'd also advise you flush out your brake fluid and replace it with either OEM or potentially something with a higher temp rating (ie, expensive) if you intend on doing anymore insane towing adventures.. this is super easy to do if you have an oil vacuum pump, have a helper keep fluid reservoir full while you just pull fresh clean looking fluid into each caliper.. wont help w/squealing at all but if you did cook your brakes then you cooked your hydraulic fluids too and fresh fluid should firm the pedal back up.

superswiss

Brake squeal is something that comes up very often and perhaps car manufacturers should educate their customers better. Squeal mostly comes down to how you use and maintain the brakes. More performance oriented compounds require more attention to this. It helps to understand how brakes are supposed to work. When brakes are new the pads are scrubbing directly against bare metal. That's not optimal and often the cause for squealing. Friction between different materials is not ideal. It doesn't provide maximum stopping power in case of brakes or maximum traction in case of tires. For example winter tires work by trapping snow, because you get most grip from snow on snow. Rubber on snow doesn't give you a whole lot of grip. Same goes for the brakes. They work best if the friction is between the pads and a pad material layer on the rotors. The process of putting down this required layer is called bedding or burnishing. Becomes more important with more performance oriented pad composites. It requires heat to put down this layer and also to maintain it. Daily driving with the brakes not getting hot actually scrapes the layer off, so with just daily driving you eventually end up with bare rotors again and then they start squealing again. Wheel cleaners that are designed to dissolve brake dust also dissolve this layer, so you shouldn't use it during every car wash as it basically washes off the layer from the rotors and you want that layer to stay. The other issue is if you don't put the layer down in a controlled manner using tried procedures, you can end up with uneven deposits which can lead to pulsing and other issues. This is what's often misdiagnosed as warped rotors. Rotors don't really warp. That's a huge myth and a convenient excuse used by many techs. It takes huge amounts of heat to really warp an iron rotor. Cheap rotors with barely any mass are easier to warp, but not the kinds of rotors Audi uses. The best advise I can give someone is to work the brakes regularly to maintain a nice layer of pad material. A rotor in optimal working order should have an even gray layer of pad material on it. If you see shiny metal instead you need to get to work and condition your brakes by following the bedding/burnishing procedures you can easily find by googling it. It basically involves repeated slowdowns from around 60 mph, followed by letting the brakes cool down. Lastly, its also possible that you overheated your brakes with towing and glazed your brake pads. That's when due to the heat the pad surface gets polished and hardened and causes squealing and reduced braking performance, so you'll have to wear off that layer or change your pads.

dreadlocks

only reason I brought up warped rotors is because he did tow a very overloaded trailer (>5 ton IIRC) through a few Colorado Passes.. on his coast to coast move (id of crossed i80 with that load personally, but ive driven every road to the west coast from here).. dont think this is the result of daily driving.. even with engine braking on steep enough grades (>10%) Ive boiled brake fluid on a much lighter trailer and had my rotors glowing a kinda red I only ever see on a race circuit.. I too highly doubt he did anything to the rotors and just needs to bed in his brakes.. but if he's like most people from outside the mountain states, he held his foot on that brake pedal all the way down a few mountains and with that kinda load, I'd want those rotors checked out.. just for cracks, gouges and excessive wear mostly.

arU4ic

I was going to mention glazing during towing thing too - change your pads.

jbgilbank

Wow! Thank you! Super enlightening! I did heat them up towing, they were creaking and stunk something unbelievable! They don't appear glazed, but they are a little shiny. I will go for the burnishing proceedure and see if that makes a difference. It still seems to stop excellent, just noisy!
I did notice today, they were not as bad, quite quiet. Trying to pinpoint in my mind when that changed and why.
As for crazy towing, not so much. My wife was completely over it kind of early on! Yikes!

jbgilbank

Thank you again! arU4ic gave quite a schooling below, so I will check as you described and try burnishing them tomorrow. I have one big tow left, just a few miles from storage. I didn't notice them as bad today.