Rear Brakes G IV: Reviews & Experiences

Hello,

When I switched to my summer tires, I noticed that the rear brakes are not in the best condition. Specifically, the right rear brake pad has about 3 mm of material left on the outer surface, and the rotors have grooves and faint markings from brake pads that were briefly stuck, even though I drive on the highway daily. The parking brake is used twice a day. The rear wheel brakes remain relatively cool during operation, so there shouldn't be anything rubbing against them.

The car now has approximately 60,000 km on the odometer, and the front brake pads and rotors look almost like new (remaining pad thickness > 9 mm, no signs of wear).

How does that all fit together?
How are your G IV brakes performing? Is the wear rate also extremely high on the rear brakes?

And one more thing about the brake disc replacement. I read in the repair manual that when replacing the handbrake cable, calipers, or discs, the handbrake needs to be adjusted. I would like to avoid this adjustment due to the interior work and the existing center console. Is this adjustment absolutely necessary? After all, I'm only restoring the original condition by replacing the pads and discs, and the cable should even be slightly longer. Therefore, there shouldn't be any rubbing, and the correct clearance will automatically be re-established by the brake calipers. What do you think?

Okay, I once had an A3 from the year 2000. I don't think there's a huge difference between those models. According to the workshop, I needed to replace the brake discs and pads because the pads were stuck. However, I only replaced the pads. The pads still had quite a bit of material left on them.

"It worked well; the brake discs were worn evenly again (the rust disappeared after a while, and the grooves were almost gone). The discs and pads were still in excellent condition when I handed over the vehicle after another 30,000 km. The front ones were more worn."

According to the workshop, both my A3 and my GIII have issues with brake pads getting stuck. In my case, it was already quite bad when I noticed it (a scraping sound while turning). However, the brakes still remained cool. Since then, I've been removing the calipers every year and using a file and copper paste to help release them. I haven't had any problems since. It's definitely cheaper than having to replace brake pads that are worn down halfway.

Depending on the condition of the discs, I would try again. Of course, use brake file and copper paste. When retracting the cable, detach it from its position and reattach it without adjustment. It should then adjust itself. You can try it and possibly make further adjustments, but in my case, it worked without any adjustments.

"76,000 km and the brake pads show even wear on both the inner and outer surfaces. However, I often don't engage the handbrake when parking."

Hi Roger,

"I had to replace the rear brake pads at approximately 60,000 km because the friction material on the outer pad on the left rear side had detached from the backing plate, was broken, and making a lot of noise. Since I replaced it promptly, there was no damage to the rotor. All the pads were significantly worn, so replacing them wasn't painful. I didn't adjust the parking brake; it worked perfectly afterwards, even though the manual says it needs adjustment. The rotors still have well over 8mm thickness and are completely unmarked. The TÜV (German technical inspection) brake test also confirmed that no adjustments were necessary."
The front brakes are still in very good condition, even with 72,000 km on the odometer!

"I recently replaced the rear brake discs and pads on my '97 A3, which is essentially the same process. It really can be done quickly. I always use the sliding tool from a disc replacement kit and a C-clamp to push the pistons back in. So far, nothing has gotten stuck. I also didn't need to adjust the handbrake, even though the old pads were completely worn down and the discs were very thin. The handbrake engages evenly and well after three clicks. Also, there are no noticeable issues during normal operation."

Okay, even though it's not technically correct, it has worked perfectly fine for me so far, and that includes with the 35i, which also has the same rear brake.

It's correct that the rear braking system is unusual. I believe Bertil once mentioned that, after completely replacing the rear brakes, he subjectively felt they braked much better.

I also don't think that the handbrake helps much. The pads are activated/moved in the same way as with the foot brake. The foot brake is usually used more often .

Using the handbrake more often will only help the handbrake mechanism itself, not prevent the brake pads from seizing.

It's obviously not possible to say that the coatings will definitely become permanently bonded. You probably experienced it already (@Roger). I had mine for about 2.5 years and around 40,000 km, while joegolf still hasn't after x years and 76,000 km...

Thank you for the feedback so far.

@Mr./Ms. Antje:
So far, there have been no other noticeable issues, no squealing or grinding noises. The significantly reduced brake pad thickness is what concerns me the most. Also, I might be experiencing a slightly different pedal feel lately; when braking harder, there's an initial firm resistance, followed by perhaps a 2mm of travel before it settles at a second point, and then the BAS (Brake Assist System) kicks in if you press even harder. However, there doesn't seem to be any air in the system; the brake fluid was recently changed and bled, and I don't think air feels like that. The braking performance seems okay overall.

I'm not entirely convinced about "Festgammeln" (aggressive driving), because I drive a lot on the highway and, when possible, also quite fast. There are often times when you have to brake hard. On the other hand, I also do a lot of stop-and-go driving, where the brakes are constantly being applied. After the wear on the brake pads, it seems like there's quite a bit happening back there.

@joegolf:
But the wear is also more pronounced at the rear compared to the front, right?

@Matthias:
How much horsepower did the A3 have?
It already reassures me that you don't necessarily have to adjust the handbrake. I will seriously consider getting new brake discs, and I will also soon adjust the caliper measuring screw. Perhaps they are already at the end of their lifespan in terms of remaining thickness - this makes the decision much easier .

"What you said about Bertil is correct; I remember it that way too, but I need to look it up."

The A3 has clocked over 200,000 km. Those definitely weren't the first brakes I've replaced on it. The driver of the car is not a reliable source when it comes to data. He only drives at full throttle until some defect forces him to bring it to me. The rear brake pad thickness was no longer measurable .

But seriously, I measured mine at 60,000 km and got something around 8.6mm. That was after several hard braking events at high speeds. I've been complaining for a long time about the weak performance of the brakes on my Golf. I even tried the V6 brake kit once, but I ended up selling it. You hear both good and bad things about Zimmermann too... I'm putting these ones on the rear now until I sell the car. If the wear continues to be this low, then it's fine.

Roger wrote:

@joegolf: But the wear is also more pronounced at the rear compared to the front, right?

Last Saturday, I could have measured that while changing the tires... I don't have a reliable way to remind myself of the front-to-rear comparison. I only paid attention to whether the rear/front pads and rotors were wearing down evenly, as I was aware of the issue. However, there was still plenty of material left.

No, I don't need measurements. That's enough.

Quote:

Muss die Einstellung zwingend erfolgen ? Ich stelle doch eigentlich mit Tausch von Belägen + Scheiben nur wieder den Neuzustand her, das Seil müsste sogar minimal länger geworden sein. Schleifen wird dann also IMHO nichts und die Nachstellung des korrekten Spiels wird gleich wieder von den Bremssätteln durchgeführt. Eure Opinion?

That's a misconception!

Over time, if the handbrake cables stretch, the brake levers on both calipers will rest against their stops, which they are not supposed to do.
If the rear brakes were to ever get really hot, which is rare in practice, it's possible that the brake pads could swell so much that the free travel of the brake piston would no longer be sufficient to properly release the brake, potentially leading to full braking of that wheel.
Therefore, when the handbrake is released, the brake levers should be approximately 1.5 mm away from the stop to allow for some reserve clearance for the brake pistons.

I've had that experience myself; it was actually fun trying to find a fault in the braking system, even though there wasn't one.
After making the necessary adjustments, everything was back to normal.


Here is an excerpt from the RLF (presumably a document or text).

Parking brake lever in the resting position. Tighten the adjustment nut until the levers come off the stops on the brake calipers.
The clearance between the brake pads and the left and right brake calipers must not be less than 1 mm, nor greater than 3 mm.
Check if both wheels rotate freely.

If not, turn the piston back.

BM wrote:

Therefore, when the handbrake is released, the brake levers should be approximately 1.5 mm away from the stop, so that there is still some reserve clearance for the brake pistons.

Hi,

If the brake levers feel "stuck" when the parking brake is released, it means the cable is already under tension. It's not completely tight, but it's also no longer loose.

Therefore, exploiting the available clearance (e.g., when the brake is getting hot) would involve tightening the chains even further... ?

Roger wrote:

@Mr./Ms. Antje: So far, there have been no other noticeable issues, no squealing or grinding noises. The significantly reduced brake pad thickness is what concerns me the most. Also, I might be experiencing a slightly different pedal feel lately; when braking harder, there's an initial firm resistance, followed by perhaps a 2mm of travel before it settles at a second point, and then the BAS (Brake Assist System) kicks in if you press even harder. However, there doesn't seem to be any air in the system; the brake fluid was recently changed and bled, and I don't think air feels like that. The braking performance seems okay overall. I'm not entirely convinced about brake pads being the sole cause, because I drive a lot on the highway and often at high speeds . There are definitely times when I have to brake hard. On the other hand, I also do a lot of stop-and-go driving, where the brakes are constantly being applied. Based on the wear on the rims, it seems like there's quite a bit happening back there.

So, in my case, the grinding issue didn't appear until relatively late. If I had checked earlier, I could have fixed it sooner.
My A3 was driven quite aggressively, almost every day with braking from approximately 200 km/h to approximately 80 km/h (leading to brake fade/rubbing). Then, my vehicle was parked on a parking garage, and pulling the handbrake tightly was the top priority . Also, my vehicle was only 2.5 years old at the time and had "only" 40,000 kilometers (km) on it. However, I can't assess the first 1.5 years and 7,000 km, as it was a one-year-old car from Audi. Nevertheless, even with my other vehicles, this wouldn't have been a reason to complain excessively, but that's just how it was. Just like I had experienced before with my GIII. Perhaps it has something to do with the fact that a lot of salt is spread here, and I don't really wash the vehicle often, and when I do, it's in an automatic car wash without undercarriage cleaning.

If you release the brake, you'll immediately notice whether the pads were stuck or not. Maybe I'm right, maybe not. We'll know for sure if you let us know what happens...

Even my friendly mechanic admitted that the A3 has problems with it. However, he was not aware of the issue related to the mass airflow sensor .

@brösel
"I also have one on each side of the GIII, but I'm not sure if they are on the top or bottom. Maybe the TÜV inspection this month will reveal something (I suspect there might be an issue with the rear brakes), and then I can check again."

@ Ulf

Quote:

Exploiting the available range (e.g., when the brake is getting warmer) would then involve tightening the cables even further... ?

You could see it this way: while it might not be the most elegant or refined English approach to creating the necessary space, it seems that the brake cables, which give slightly, provide the missing clearance for the brake pistons.

Hello,

With my '96 Passat, the brake pads (the very first !!!) on the rear axle lasted until a mileage of 105,000 km. Then they were worn out - and the rotors weren't really usable anymore either. I replaced the front pads and rotors (also the first set of pads) at 115,000 km. Of course, there was a lot of long-distance driving and gentle braking.
I can only explain why the rear axle wore out faster by assuming that there was less clearance at the rear than at the front. At the front, steering movements and the larger disc radius create more clearance, whereas at the rear, this results in more wear during driving.

"In newer vehicles like my Passat, which are equipped with ESP systems, the rear axle is inherently "more strongly" braked in the partial braking range. ESP includes an EBV (Electronic Brakeforce Distribution) function. The brake pressure gradient or build-up at the rear axle is no longer mechanically limited but electronically controlled. The brake pressure is reduced by releasing pressure through the ABS valve outlets when wheel slip on the rear wheels exceeds that of the front wheels (to ensure vehicle stability and prevent over-braking of the rear axle). When EBV is active, you can notice it by a slight "stepping" sensation in the brake pedal."
However, all of this also means that in these vehicles, within the partial braking range, more braking force is applied to the rear axle than in an older Golf II, which consequently leads to increased wear and tear!

Happy Easter .

"That sounds interesting, especially the part about EBV. Does that mean my second resistance point in the pedal is caused by that? I somehow didn't notice it before..."

It makes sense to me that the rear disc brakes, without a mechanical brake force distribution system, tend to apply more braking force under partial braking loads. However, this should also be taken into account when sizing the rotors and pads. In practice, though, the same "child's toy" brakes are still being used in the rear as before.

"Nevertheless, my G III GTI (model '97) had the VR6 brakes and also already featured ABS with EBV. The same issue should have arisen then (under similar driving conditions as now with the G IV). However, it easily reached 100,000 km using the original brake pads all around, and at the time of sale, it still had usable remaining pad thickness everywhere."