tomashek

Hi all,
So swapping pads will help for brake dust, but will it eliminate freakish squeaking brake sound when car comes to complete stop? I tried bedding, but it helps for couple days only and squeaking noise comes back. When I gently release brake pedal when at stop – it starts rolling slowly and it makes this horrendous squeaking sound.
So, is it a brake pads problem? Will swapping those help?

warcity

iTrader: (1)

I asked Audi the same question last week. Audi break pads are primarily made out of ceramic (for much better stopping power), squeaking is perfectly normal for such break pads. If you swap them for traditional break pads you won't have as good breaking power and you'll have plenty more break dust.

Unfortunately because we've had an extra dry summer that's not helping the squeak either. Audi said basically it's a live with situation but as soon as the weather cools down a bit it should go away.

cheeba

This is incorrect. Some ceramic pads have higher coefficient of friction than non-ceramics, but it is certainly not always true. The only way to know is it to reference a coefficient of friction vs. temperature chart. And, squeaking is never 'normal' - it happens when one (or more) of the three conditions I mention below are met. The only time I would call squeaking 'normal' is when you're purposefully running a high-temp pad and it is not up to temperature yet.


Nearly every time (and I'm talking a serious 99+% here) someone complains about a specific brake pad, it is because of the one of the following:

1) Improper installation

2) Noise from lack of grease on the backing shims and/or sliding pins

3) Incorrect choice of compound for the application and heat range


Selecting brake pads is just a series of compromises, and most people have no idea what they're doing in that regard. Furthermore, OEM engineers are not infallible in this regard as they are constrained by many things: suppliers, budgets, regulations, but most importantly selecting a pad that will suit the average driver. Learn about the aspects of pad compounds (temp range, coefficient of friction, cost, noise, availability, etc.), decide what compromises you are willing to make and select your pad accordingly, then perform a proper install. Good fluid and a proper bleed (something you are very unlikely to get at any shop) is essential to brake performance as well.

warcity

iTrader: (1)

My S4 was squeaking from day one. On 2 occasions I had audi told me this is normal. What are the chances of improper installation and lack of grease? On a new car? Specially last time they were inspected by Aud they were no mention of any issues.

cheeba

The chance of improper installation from the factory is very small, but the chances of improper installation by subsequent techs, even Audi-trained ones, is very high. I'll PayPal you cash for a pint of beer if you can find a single Audi tech in your city that beds in brake pads and/or rotors properly after installation, or even knows how to do it! I'm not sure why you think that someone you speak with, or a tech, from Audi are going to be experts, but I can assure you that that is very unlikely. You're much better off talking to a mechanical engineer, or better yet, an avid race racer. I know I speak frankly and strongly, but that's only because when I do, I am sure of what I say – I back up everything I say with facts, and a strong understanding of, and practical experience with physics, mechanics, and vehicle dynamics specifically.

As I said above, there are many reasons why Audi would not select the perfect brake pad compound for any given vehicle. I outlined the basics to research so that people can learn for themselves rather than have blind faith about something that is fact based.

tomashek

So you think that asking dealer to apply some sort of brake grease will help my issue?
I'll try it if it's worth it, wonder why dealer didn't suggest it when I reported it.... It seems to be a quick thing to do, so why wouldn't they try it....

cheeba

How could I possibly know that without seeing your brakes?

I outlined the common problems with brakes, which comprises nearly all brake issues. That said, I highly doubt it's a lubrication issue since it seems to be happening to many people straight out of the showroom. It's more likely to be a pad selection issue (more likely), or perhaps small design flaw in the system that is creating some feedback (less likely), in which case Audi will not fix it unless it's for one of the following reasons: a safety issue which they deem to be a serious financial risk, it escalates into an issue that causes enough bad press to justify the cost of a recall, a successful class action lawsuit, or possibly if you make enough stink about it that they just want you to go away.

VAG has been sued many times for shoddy parts selection – it's not exactly uncommon in the auto industry. If they designed a timing belt system that fails prematurely with regularity, thus destroying entire engines, is anyone really surprised when something like a squeaky pad shows up? And they had to be sued to eventually own up to the timing tensioner issue

rocco_ca

Why would Audi mechanical engineers design cars with improper parts and design flaws ?

We are in a high end market segment here and there is no excuse for this as they have test facilities.

The benefit to Audi would have to be more money being made on fixing these issues.

Car issues after the warranty runs out would be logical, but why do these issues happen right after the cars leave the showroom? So the dealers make money on fixing them?

I've had my Q for 1 year and been to the dealer for oil consumption issue of which they intend to fix over a 2 week period by removing my engine and taking it apart to investigate internally.

A more recent issue is cold engine start misfire which they will fix by replacing the crankcase pressure regulating valve, seal , and crankshaft bolt.

I'm basically sad because I really love my car. I love the way it drives and it's design .

I'm just disappointed and trying to make some sense out of all this.

cheeba

Many reasons, but they all distill down to a single metric: budget vs. riding the technological edge of human advancement. A team of F1 engineers and an unlimited budget could build a 250HP 2.0L car that would perform amazingly, and last hundreds of thousands of KM with nothing but standard consumables maintenance. But that would cost three million dollars. Likewise, a team of Audi engineers with a regular A4-type budget could build a 100HP 2.0L car that performed like crap, would be loud and noisy and unrefined, not meet safety and environmental specs, but is just as reliable as the aforementioned imaginary car. But no one wants either of those things – the F1 engineers push their skills/materials/physics to the absolute edge (and things break) so that they can win races; the Audi engineers do the same within their given set of parameters (budget, materials, suppliers, more limited knowledge, reliability, etc.) so that they can sell cars.

Think about how difficult it would be to design an entire car from the ground up (ignoring the fact that VAG has a vast parts bin to build from): thousands of parts designed to rather strict tolerance, using the appropriate materials, all working together to accelerate a 2200KG hunk of metal from 0-100km/hr in 4.5 seconds. Now imagine the logistics of doing that in conjunction with hundreds of people, under time and budget and supplier and manufacturing constraints; and, don't forget to make it quiet, refined, and fun to drive with good dynamics. Oh, and it has to be reliable for every type of driver in every climate and environmental condition in the World. Again, it could be done – indeed quite easily. But can it be done at a marketable price point? That's what makes it difficult.

That said, if I had to guess, I would say that the brake squealing is incorrect pad selection for your driving habits and climate.

rocco_ca

Why is it that automobile manufactures like Acura, and Infinity are able to balance all their parameters and end up creating very high tech cars that are extremely reliable?

I'm thinking perhaps Audi engineers are the inventors of new technology and learn by trial and error ? and companies like Acura and Infinity use older proven technology ?