Leon Bj05: Weak Brakes (Fixed?)

Hey guys,

I'm starting to get really stressed out...

So, here's what I did:

- Timing belt replaced.
- Take it out of gear.
- ZMS (torque converter) and clutch replaced.
- Reinstall the transmission software.
- Front brake discs and pads replaced.

Current status:

- The engine, transmission, and clutch are in good condition.
- The brake pedal is hard, but the braking performance tends towards zero.

Done.

- Brake bled with a bleeder.
- Run the ABS pump for at least 10 seconds.


My VAG-Com is an old 409.1 US version.
I bought the adapter a long time ago as a used "Ross part".
I have absolutely no idea whether this is the original or not...

I probably don't have an ABS bleed function (yet).


Regarding the symptom again:

- It feels like the power brake assist has failed...

Just to be aware that in the event of a brake booster failure, significantly more braking power will be available!


Axo, I just remembered something:

- I had an error message, which I unfortunately didn't save.

"Brake pedal signal not plausible."


I think I urgently need help!!!

Hello,

The ABS bleeding process for your vehicle is performed through the actuator diagnosis function, which requires a licensed VCDS/VAG-COM software.

Is your brake pedal spongy (= brake system not properly bled or leaking), or do you have a hard pedal feel but very weak braking performance (brake booster not receiving vacuum or faulty brake booster)?

Best regards, Rainer.

Does anyone have any ideas?

Unfortunately, you've run the fluid reservoir dry, and now there's air in the control unit's valve block. This has happened to me before too.

Quote:

Just so that in the event of a brake booster failure, significantly more braking power is available

.
Don't be mistaken.
There are two ways to fix this: Either solution A, which is what Rainer suggested (and would be beneficial for a car of your age anyway), or...
You can either go to a Seat dealership and have them perform a guided actuator diagnosis for brake bleeding. The cost is approximately €50-100 for about half an hour of work. That's my experience.

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Men,

Thank you both!

Yes, Rainer, then I probably have to become a customer in the new month...

I've read it and understood it!

But I have a small update from the front lines!


I have one wrongdoer.

The rubber on the brake booster is leaking.
After a bit of wobbling and twisting of the "Nipfie," a hissing sound could be heard.

@rainer

The resistance from the pedals was immediately very stiff, with very little give.

...now it's softer and the braking force has increased!

I'm going to replace that part right away. Then we'll see how it goes.


Why do such errors always occur after completely different kinds of tinkering?

pit von DO wrote:

Why do such errors always occur after completely different kinds of tinkering?

Because it involves moving all sorts of (potentially fragile) hoses...

Okay, the initial problem has been resolved!

I have to hold myself accountable and admit that I made a mistake...

When removing the transmission, the engine needs to be lowered on the transmission side.
Sure, we know that. And we have to remove all the hoses and cables that could get in the way.
disconnect, or remove from the way.

I also thought that I had done that...
I overlooked the vacuum hose that connects the tandem pump to the brake booster.
It detached on its own. In the process, the rubber bushing in the BKV (hydraulic control unit) tore!

That was the main problem!

Okay, the car is braking very nicely again! I'm going to take it to the TÜV (technical inspection) as it is, and then we'll see.
continue.
I encountered the same error message on my last trip, even though the BKV (presumably a system or device) was malfunctioning.
"Received an implausible brake pedal signal," but I'm still investigating the cause.
Follow-up errors, and I'll ignore it for now.

Thanks again for the tips!
@Rainer - I'll get in touch with you regarding the next payment after that one!