Rear brakes intermittently sticking on Octavia RS TDI

Sometimes the rear brakes on my 2007 Octavia TDI RS get stuck.
For the first time, it happened at approximately 60,000 kilometers after an inspection. Loosening the handbrake cables resolved the issue.
Then, during the next brake pad replacement on the rear axle, the right side was stuck. The rotor even started to warp slightly. Strangely enough, the problem resolved itself.
Now, at 168,000 km, I replaced the rear brake discs and pads, but the problem has returned! However, the rear right caliper was repaired because the seal was defective.
The problem seems to be shifting around! Sometimes it's hot on the left side, sometimes on the right. I adjusted the handbrake according to the instructions and bled everything. The caliper was pre-filled.
Yesterday, I adjusted the brake fluid level so that it was exactly between the "min" and "max" marks. After that, the problem didn't reappear for a short time. Today, on my way to work, the right side is hot again. I'm starting to get desperate...
"Does anyone have any suggestions on where else I can look? The brake is made by TRW."


Regards,
Daniel.

Could the handbrake be adjusted too tightly?
After replacing or servicing the brake calipers and reinstalling the pistons (tightening them!), I always apply the service brake several times before engaging the handbrake.
Were the pistons perhaps pushed back incorrectly?
hg
Herbert.

Wie gesagt: Alles streng nach Leitfaden und mit entsprechendem Werkzeug. Selbst die Rückstellmechanik habe ich mir nochmal angeschaut. Works.
Just now, on my way back from work, both rear tires were cold again. And this was even though I was driving at speeds of over 120 km/h on the country road.
It's noticeable that it seems to be working better after I only filled the expansion tank halfway. There's a similar thread in this forum, but unfortunately, it doesn't offer any explanation about the solution.
The saddles are free and move smoothly. The pads inside the saddles also work well.
That's the problem. It seems like everything is free-moving, but somehow the piston sometimes can't return.
Ideally, this is when new coatings or similar materials have been applied beforehand.
The only thing I haven't tried yet is performing a basic reset of the ABS system. Although, I'm not sure if that would make any difference.


Best regards and thank you.
Daniel.

It definitely has nothing to do with the brake fluid level or the ABS system. The problem lies with the brakes at the rear or the handbrake.
How many teeth can you pull on the handbrake lever without any resistance?
hg
Herbert.

Is the Octavia model already a sister car to the Passat 3C? Or is it an older model?

For the rear brakes of the 3C, there are two different brake pad types from ATE that are sometimes incorrectly installed. The wrong pads will fit, but they can often cause problems and seize up.
See, for example, here: http://www.passatforum.com/forum/viewtopic.php?t=30901#p406996

Perhaps it will also be helpful for yours.

In addition to the observed fault, it is important to check the ease of movement of the pistons, the floating saddle, and the pads themselves. How were these components cleaned and treated with preservatives?

Greetings.
Sure.

Here is the translation of the text from German to English:

"Guste" means "gust" in English. It refers to a sudden and strong gust of wind.

"Everything is easy to operate. The brake pads release easily and fit perfectly. I've tested the handbrake in all settings, from very loose to fully engaged. Currently, it engages after about 5 teeth. This matches the readings I got from the Audi that's still here. It also engages after 5-6 teeth."
Could the HBZ be the cause? That would be the next "convenient" alternative to exchanging [something].
The brakes themselves don't present any problems. The pedal feels the same as always.
Due to the ABS system - the manual states that after bleeding the brakes, you should perform the basic adjustment.
Here's the translation:

"It also states: If the brake pads are new or far from the wear limit, the brake fluid level should be between the minimum and maximum marks. I think they mean it should be in the middle. I've already disabled my Hill Hold Control (HHC), but without success."
Sometimes I miss my old Golf Mk2.

Edit: Just after 26 km, I'm already stinky and hot again. The wear pattern on the tires looks a bit strange.



Regards,
Daniel[/img].

Upon arriving home, I noticed something. The engine is off, but the ignition is on. There's a faint clicking sound coming from the area of the hydraulic brake booster (HBZ). When I press the pedal, it clicks again. It sounds like the brake light switch, as the brake lights are also activated at the same time. However, the clicking doesn't always happen. Sometimes I can press the pedal 20 times without any clicking, and the brake lights still work.

Regards,
Daniel.

Think about it. We're talking about a diagonal two-circuit brake system.
It is simply impossible for the master cylinder in a brake circuit to cause a malfunction at the rear while not causing one at the front.
The fluid level is not relevant; the instructions only address adjustments based on wear of the disc.
Again, what about the path of the handbrake lever?
hg
Herbert.

Herbert wrote:

Nochmal, was ist mit dem Weg des Handbremshebels?

iiciaii wrote:

Aktuell komme ich auf 5 Zähne.

To be absolutely sure, one could simply loosen or detach the ropes completely and drive.

Overlooked. Five teeth should really be enough.
hg
Herbert.

"The system was initially set to a completely loose configuration. When the error occurred, it was adjusted according to the guidelines in order to rule out that setting as the cause. The strange thing is that after about 200-300 kilometers of use, the problem seems to disappear. It appears that some people are experiencing this issue without actually finding a specific fault. Using a two-circuit system makes sense!"
It's likely the problem would be fixed if I removed 1-2mm from the surface of the material. However, that wouldn't address the root cause, and that bothers me. Everything seems normal and functional, but the problem keeps recurring, and it's incredibly frustrating to try and figure out why.
The handbrake engages relatively early, but I'm used to that; my wife's A4 has the same issue.
Does anyone know the distance that the brake lever arms travel on the saddle when the handbrake is engaged? When at rest, the gap between them is typically 1-3mm combined. I've already checked the piston to make sure it's retracting properly.

Regards,
Daniel.

Quote:

When at rest, the distance between them is typically 1-3 mm when measured together.

When the handbrake is engaged, the levers (on the saddle) must be fully pressed against their stops. This is the basic adjustment.
If there's still a little slack in the cable system (...,the handbrake is engaged relatively early...), the brake will rub.
hg
Herbert.

Herbert wrote:

Think about it. We're talking about a diagonal dual-circuit brake system. It is simply impossible for the master cylinder in a brake circuit to cause a malfunction at the rear while not causing one at the front. The fluid level is not relevant; the instructions only address adjustments based on wear of the disc. Again, what about the path of the handbrake lever? hg Herbert

.

It's not entirely impossible; in fact, I've encountered swollen brake hoses twice that have obstructed the return flow of brake fluid.

The bearing surface looks suspicious; are the saddle guide bolts excessively loose and potentially misaligned?

When the brake is released, there must be a minimum of 1 mm and a maximum of 3 mm of clearance. It would be incorrect if it were at its limit. I still got the TÜV approval today. The inspector said that it would improve over time .
Bremswirkung war soweit okay. Bei Gelegenheit werde ich mir die anderen Bremsschläuche/-rohre nochmals anschauen. Aber auffällig war bisher nichts. Hatte sowieso die erw. HThat's outrageous.

Regards,
Daniel.

So, it's not that bad after all? Yesterday, the HBZ was still a potential replacement candidate. Then we can close the thread without worrying too much about the cause.
hg
Herbert.

The problem persists, and the cause is still unclear. However, I fear that nothing will be found, especially after reading through the usual discussions about this issue.
My guess is that the piston is stuck in its rearmost position, for some reason.
It's strange that this problem affects so many people.

Regards,
Daniel.