Soft Brake Pedal: Fix It by Pressing?

Evening.

Sure, here is the translation of the text from German to English:

"This refers to the 3BG (Bundesliga) in the signature."
The rear brake caliper had leaks at the brake lever, making it difficult to apply the brakes (the brake pedal would go all the way down). It was replaced today.
Currently, the problem remains that I can still fully depress the pedal, but only when the engine is running.

In my opinion, it's related to the HBZ; can anyone confirm this?
It seems the brake fluid is no longer leaking, and I've bled the brakes twice using an electric vacuum pump, completely removing all air bubbles.

Best regards,

Was the brake caliper replaced?
hg
Herbert.

Hello!

Regarding the HBZ (presumably an abbreviation):
He's only 19 years old, so things can sometimes break down. Usually, it happens when someone forces it too much during repairs or bleeding. The seals end up in a position they might never have been in before, and where everything is already corroded and rusted.

I don't think so; that's really rare.
To test it, you can turn off the engine and gently press the brake pedal, just barely touching it, and then wait. If the hydraulic brake booster (HBZ) is leaking, eventually, with a slow and steady pressure, you will be able to depress it all the way down to the floor.

Another option is to close the connections from the main distribution box with blind plugs; this is the most reliable way to ensure they are sealed.


If (there is still) air in the system, which I suspect is the case, the brake pedal can be "bled" to remove it.
Also 5 x ganz fix pumpen, dann hat man einen vernünftigen Druckpunkt. He also holds [something].
If you then release the pedal and wait for 5 seconds (while the compressed air bubbles expand again and displace the brake fluid), you can press the pedal further down again.

Bleed:
Ja, das geht manchmal wirklich schlecht. Depending on the type of car.
I've struggled with that for hours before.
I used to have a similar electric device, but it wasn't very good.
Now I have an air compressor, which works much better.
"Sometimes, I also use a compressed air device for bleeding brakes, and then have an assistant help me pump the pedal with their foot. This is also useful because the assistant can see if any air is still coming out and where it's coming from. So far, this method has solved all my brake bleeding problems."
Even though it was sometimes quite a struggle.

"Thank you!"

The brake caliper was replaced today.

I've also tried the inflating method before, but after 5 or 6 kicks, it still deflates and can be reinflated by pressing.

When the engine is off, I can't press the accelerator pedal no matter how hard I try, and the brake pedal also becomes very stiff.
I'm going to try and "blind" the HBZ tomorrow; that's a very good idea.
If it's appropriate here, I will bleed the system again with the help of an assistant.

Do I need to access the ABS module using VCDS to ensure that all air is removed and old fluid is drained from the system?

Hi!

I'm not sure what kind of braking system you have. This car is a bit of an oddity.

Have you ever tried just turning on the ignition without starting the engine?

My old Corrado had an all-electric braking system, and I think (sorry, it's been a long time), at least partially, the brake lines were bled using pumps within the brake assembly.
That worked really well, if you knew how.

Well, I wouldn't exactly call a 3BG Passat an exotic car .

If the problem is related to the wheel bearings, are the repair kits worth it, or is it usually not worthwhile investing in them due to rust or other issues?

Hi!

Sorry, I was lost in thought about the S 6.

That issue with the electric brake is also resolved now.

To be honest, I haven't installed a replacement set of parts for the HBZ yet.
I wouldn't do that either, unless it was for a rare or exotic classic car and there were no other options.
Exactly because of the dirt/rust/wear and tear.

However, I have to say that I haven't changed my health insurance provider in the last 10 years.
Overall, throughout my life, including during the East German era when cars were sometimes 30 years old and no one ever changed the brake fluid, this has happened on occasion.

But since 1990, with what are known as "West cars," having replaced five distributors is quite excessive. And that's only the case with very old and poorly maintained vehicles.
I don't believe it.

Sure, here is the translation of the text from German to English:

"Addendum:"
Sensitive, anxious, and easily offended individuals can sometimes be a problem for auto repair shops.
"Sometimes, there are issues where people report that the brake pedal sinks to the floor when idling after brake repairs, especially in diesel vehicles."
People then press down hard on the brake pedal, something they would never do during normal driving. This is simply to test whether everything is working correctly. Newly installed brake components can also contribute to this issue.

I once attended a training session by ATE where this was a topic of discussion. I think if I search tomorrow, I might still be able to find some documents about it; I remember it quite well. It was a description of how to explain to the customer why something is the way it is.

Have you ever driven a car, like on the driveway, very carefully, and just tested the brakes?
If everything is completely sealed and the brake cannot be pressurized, you should try this.

Quote:

Have you ever driven a car, like on the farm, very carefully, and just braked? If everything is really tight, and the brake cannot be pressurized, you should try this.

I also experienced this phenomenon frequently with my previous car (3BG). While the engine was running and under heavy load, the accelerator pedal would sometimes sink almost to the floorboard. Without any boost pressure, the pedal felt completely stiff.
Everything was normal during operation.

What was the brake pressure like before?

Autoservice wrote:

I also experienced this phenomenon frequently with my previous car (3BG). While the engine was running and under heavy load, the accelerator pedal would sometimes sink almost to the floorboard. Without any boost pressure, the pedal felt completely stiff. Everything was normal during operation. What was the brake pressure like before?

According to an ATE technician, this is normal. The brake booster is designed to provide so much assistance that the brake pedal can be pressed all the way down to the floor pan.
If it's hard to turn when the engine is off, then everything is okay.

Hi there,
During driving, the braking performance is completely normal.
The maximum delay at 50 km/h was easily manageable.

Engine off: The pedal is rock hard and also very sensitive; there's no way to press it all the way down.
Engine on: With force, it can be pressed down to the ground, and after pumping five times, this is possible again.
Otherwise, the braking behavior seems completely normal, which is something I haven't experienced before.

Comparing the pedal travel to the clutch engagement point, I believe there are still a few centimeters missing before it truly makes contact with the ground.

Quote:

According to an ATE technician, this is normal. The brake booster is designed to provide so much assistance that the brake pedal can be pressed all the way down to the floor pan.

Das ist blanker Unfug. In der Situation wäre keine Reserve mehr in der Bremse. Irgenwo müßte die vom Kolben verdrängte Bremsflüssigkeit ja hin. Also
- somewhere, there's air.
- Brake fluid is leaking past a seal.
- excessive travel of a brake piston.
- Brake hoses are expanding excessively.
- Piston stroke in the internal combustion engine is too short.
Was the brake cylinder on the replaced caliper properly adjusted according to regulations (automatic adjustment of the parking brake)? The foot brake must be applied repeatedly until the piston has fully extended and cannot be pushed back any further. Only then, if necessary, adjust the parking brake.
Before you start looking elsewhere, double-check everything on the replaced brake caliper, including the bleeding process.
hg
Herbert.

He calculated that for us.

Vacuum, membrane size, translation of "foot brake lever", foot force.

There's so much force involved that it prevents the seals from working properly.


I've had several of them that work normally, but if you press the brake pedal while the engine is running, it goes all the way down to the floor pan.

Without support, it will be extremely difficult.

The brake hoses were all replaced yesterday in preparation for the upcoming vehicle inspection (TÜV).

I received the new brake caliper in a retracted position, installed it, bled the brakes, and tested the braking system. The parking brake engages quickly and evenly. Afterwards, I bled the brakes again, starting from the hydraulic line with the longest path to the one with the shortest path.

This morning, I also noticed a rattling sound on the front passenger side, and I'll take the opportunity to bleed the brakes again.
Is it advisable to control the ABS module using VCDS?

@Autoservice
The brake pressure before was the same as it is now. I believe it's been like this since I bought the car a year ago. But you do get used to it when things gradually get worse. However, in my parents' A4 B6, there's a big difference; just a light tap on the brake and the car stops. The braking system is the same in both the Passat and the A4.

Autoservice wrote:

I also experienced this phenomenon frequently with my previous car (3BG). While the engine was running and under heavy load, the accelerator pedal would sometimes sink almost to the floorboard. Without any boost pressure, the pedal felt completely stiff. During operation, everything was normal.

The same thing happens with my Audi A4 B5 Quattro.

I'll just leave it as is; I've noticed the same thing in other vehicles this week.

"What I've noticed three or four times this week is that when the steering wheel is fully turned, the ABS activates on the front right side, even though I've already released the brake pedal."

"Please check the distance between the sensor and the sensor ring."