A3 8PA Bremse hinten links schleift | Posts 16+

Hi!

Here's a quick check after 15 km on the highway at approximately 130 km/h. No braking was applied from a cold start. Outdoor temperature: 20°C.
Slightly elevated temperature on the right rear. This is also noticeable when the wheel is turned freely. However, the right side hasn't been slowed down as much as the left side (unintentionally).

LG
Brezelmann01

Is the initial tension of the handbrake cables correctly adjusted?

I think many people are not really aware of that. Probably not to you either... you would probably have answered Herbert's corresponding question.

According to the manufacturer's specifications, when properly adjusted, there should be enough preload so that the brake levers on both calipers have approximately 2mm of clearance from the stop when the handbrake is released. You are NOT supposed to be at the ready .

Why?

Sometimes, the automatic adjustment mechanism can adjust so far that the brake caliper piston cannot retract sufficiently when the brake pads are swollen (hot), because the adjustment mechanism only allows for a certain amount of movement. Are the above...? However, if the pedal is hitting the floor, the problem might be compensated for by the "dead travel" of the handbrake cables.

It is precisely when the brake pads are being replaced, or when a complete braking surface has not yet been established, for example, due to dirt behind the outer brake pad or due to brake caliper mounting brackets that are no longer perfectly aligned, that these problems arise. These issues can often be resolved with a little more clearance in the handbrake mechanism.

I would like to:

a) Retract the piston.

b) Perform the correct initial adjustment of the handbrake.

c) see what happens.

Hello Auto Service.

Thank you for the detailed answer. I am very much aware of that, but during the troubleshooting process, the handbrake was not engaged at all. I wrote that.

Now the parking brake is adjusted according to the repair manual. The specification states that the total distance on the left and right sides must be between 1mm and 4mm. Your specification is already questionable and not a factory setting. When considered individually on each side, the factory specification defines a range between >0mm and <3mm. Everything according to the repair manual.

Apart from that, the troubleshooting and resolution process was successfully completed as described.


Regards,
Brezelmann01

Hi,
I had these disc brakes on the rear of my faded Audi 80.
The requirement during installation was that when the handbrake lever is fully engaged, one saddle should not move relative to the other. That makes sense too.
Why?
"When the handbrake levers are pre-tensioned, the amount of movement of each individual lever when the handbrake is released is not clearly defined. It can be asymmetrical, depending on the condition of the mechanism, and can change from time to time. And then it can happen that one lever is engaged, you brake, and the automatic adjustment then kicks in." And just like that, you have a brake that's set too tight.
The more pre-tension, the higher the risk. Inexpensive brake calipers can cause further problems if the internal components of the calipers also vary in quality.
hg
Herbert.

brezelmann01 wrote:

Hello Autoservice. Thank you for the detailed answer. I am very well aware of that, but during the troubleshooting, the handbrake was not engaged at all. That's what I wrote.

That's already the first point. Error.

Quote:

Now, the handbrake is adjusted according to the repair manual. The specification states that the total distance between the left and right sides must be between 1mm and 4mm. That specification is already questionable and not a factory specification.

That's why it was an approximate value, meaning roughly 2mm per side, but this information was included within the manufacturer's specifications. What's questionable about that? ... unless you're counting peas.

Quote:

Each page is individually assessed, and according to factory specifications, the thickness is defined as being between >0 and <3mm. Everything according to the repair manual.

Here, you can also see how large the tolerance range is.

Quote:

Apart from that, the debugging and elimination of the error, as described, has been successfully completed.

My post was more intended for posterity than for you. It's not hard to see that you had already fixed the problem.

Hello,

My first post in this forum, and my heartfelt thanks to Autoservice. The reference to "posterity" applies to me in this case.

I had a problem where the new caliper on the rear left side would not fully open after the brakes got warm or hot. (This resulted in a loud scraping and grinding noise, along with heat buildup in the brake).

I've already tried everything (literally everything) and checked it all.

I wasn't aware of the proper way to adjust the parking brake until now. The small lever, where the handbrake cable is attached, was always at its maximum limit, which meant that the handbrake appeared to be disengaged.

To put it simply, a 1.5mm washer was placed between the lever and the stop on the brake caliper, and the basic adjustment was performed on the handbrake lever. After the adjustment, there is a gap of approximately 1mm on the left saddle and 1.5mm on the right saddle.

The guide provides a clearance of more than 0mm and less than 1.5mm.

What can I say, the brake is now working as it should (the caliper is releasing properly).

Next, the ABS module would have needed to be replaced as a last resort, but in my case, that wouldn't have been the solution to the problem.

It was also new to me, as I was used to it being different in my other vehicles.

Thank you very much, and hopefully this will help another "suffering" person.