Brake Performance: A4, B5 & More in Heavy Rain

Hello fellow enthusiasts,

I am aware that the A4 can experience problems with the brakes when driving on wet surfaces.
'But today, after a long drive on the highway in the rain and snow, I almost lost control in a curve (my speed was adjusted to the weather conditions). I tried to brake, and for about 4 seconds, absolutely nothing happened! Luckily, after I took my foot off the brake pedal and immediately put it back on, the braking performance returned to almost normal. There are already some 'DIY' solutions for this problem that are not approved by the TÜV (German technical inspection agency). My question is, can other A4 drivers confirm my experience? And has or has there ever been any modifications for this from VAG (Volkswagen Group)?'

EDIT: Would perforated discs (assuming the holes aren't blocked again) potentially alleviate the problem somewhat?

What surprises me about this is:

Neither my old 'alt-opa-kiste' (a humorous term for an old car) nor my Octavia has had any problems in wet conditions.
It doesn't matter whether it's summer or winter, or whether you're on the salted track...
And there's more than enough moisture here right now...

Something must have gone terribly wrong at Audi.

CU Gremlin.

Well, we haven't had any problems with our Passat 35i either.

Best regards, WarLord.

It seems that only the A4 B5 model is affected by this issue. I recently scolded a friend of mine for reading similar reports. The braking performance of my A4 has always been worse in wet conditions compared to dry conditions -> is this largely normal?
It was really intense today, which is why I'm asking this question.

Hi,
As far as I know, Audi used to offer/still offers splash guards that can be retrofitted.

Yes, that's right, there used to be a conversion kit, I think made of plastic, that you would mount underneath the engine cover, near the wheel arches.
In my opinion, this product isn't suitable because it hangs down about 3cm, and you would probably end up trimming it off anyway after a short time.

Hi everyone,

'These plastic things were installed by the factory at their expense. They definitely affect the underbody aerodynamics, and the benefits are limited. When I brake into an exit ramp after driving 20 km on the highway, it's always an experience. I was able to test drive an A4 with ATE Powerdiscs, so I immediately ordered them, and they've already arrived - I just don't feel like tinkering with them in this cold weather.'

I'm now curious about the constructive differences between the A4 and the Octavia.

There has to be something different there, either in the airflow or in the combination of disc and pad.

Last winter, I drove about 40 kilometers on the A7 highway, which was soaking wet and covered in salt, without brakes, until Aunt Erna pulled out in front of me. When I pressed the pedal, it felt like it was going to pull my teeth right out of my jaw.
'This winter, we've had absolutely no problems, as we've certainly had enough rain and salt.'

The only thing I've noticed negatively in the past is that some of the brake parts were not original. It doesn't matter what brand they were.

Does anyone here have contacts at relevant organizations?

CU Gremlin.

Gremlin wrote:

I'm now actually interested in the constructive differences between the A4 and the Octavia.... Something must be different there, either in the airflow or in the combination of disc/pad.

It's not just the Octavia that's different. With my Audi 100 C4 and all its predecessors, I never experienced such a problem.
However, a few days ago, something similar happened to a 1996 Mondeo. In that case, it was only on one side, resulting in an unintentional lane change. Not very good.

Hello everyone.

I have an A4 Avant Q with a 2.5 TDI engine (AKN). The previous owner upgraded it with Porsche/Brembo 322x32mm brakes after experiencing similar traumatic situations. It's a dream to brake with this setup. The brake discs last for about 60,000 km. However, before you consider doing the same, keep the following in mind: You'll need at least 17' winter tires, the disc is modified and only available from a specialist tuner, and I'm currently preparing for the TÜV (German technical inspection). A set of discs, pads, sensors, and calipers costs around €800 just for the parts; the installation is relatively simple, though. At least, I often compensate for the improved braking performance with my confident driving style.
Conclusion: I wouldn't do it that way again.

I chatted with a colleague yesterday.

He used to have a 2001 Passat (1.8T) and now, for the past six months, he's been driving an Octavia (ASZ) as a company car.

He almost crashed twice with the Passat, mainly due to this moisture problem.

He's completely thrilled with the Octavia's brakes. No matter how long you drive in the rain or even in a salt solution, pressing the pedal gives you an incredible amount of stopping power.
On Monday, I drove about 30 kilometers on the salted federal highway without being able to brake. When I got to the exit, I almost bit the steering wheel because there was a layer of solid rust forming.

red card for Audi and VW!

Does anyone know anything about the differences between the Passat and the Octavia? Isn't the braking system essentially the same? Could it just be due to the air intake system?

CU Gremlin.

Hi,

I've dug up the link to the workaround again.

http://www.a4-freunde.de/faq/nassbremsloesung.shtml


@Gremlin:

Are the windows in the Octavia possibly packaged in a similar way to what is shown in the link?

Hi,
Am I correct in understanding that the A4 comes from the factory with only that tiny metal plate ("before")?

That's what it looks like!

Marco wrote:

That's what it looks like!

Well, I guess the question of "why" has been answered.

Maybe this will be helpful.

http://www.passat3b.de/phpBB2/viewtopic.php?t=12647