A3 8v Brake Pad Sensors
- Thread starter Allcorn
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No not the same go on euro car parts website or gsf auto. My a3 8p has the larger pads on the back. It will show you various ones
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No rear brake pads does not have sensors or wires connected.. It is basically synced with fronts so fronts has wire so pads are wearing equally fronts and backs... So when u see "brake pads" on dash means u need to replace all round
Sorry but my 2011 A3 8P has the wired sensor on my rear pads. How can front sensor make up for back. What happens when pads wear unevenly
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I don't think the brakes are "synced" to wear evenly. Fronts do around 75% of the braking, so will wear much faster than the rears. If you've been told different someone is making money out of you needlessly replacing rear pads.
I'd be interested to know re sensors in the rear pads too. I don't think it's that common to have them fitted, and I've always assumed (but never really thought about it) that they were fitted to the fronts only. Perhaps because they're engineered to last the life of a rear disc? When the disc is done, change the pads.
Sean6211
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No, there aren't the traditional wired sensor for the rear pads on the 8V platform.
The rear calipers are electronic actuated, and part of the process of pad renewal is to use VCDS to reset the calipers to account for the thickness of the new pads. This means the ABS module knows the starting point for the new pads, and based on the rotation of the actuator motor each time the parking brakes are applied, it can guesstimate the approximate thickness of the pad remaining.
The rear calipers are electronic actuated, and part of the process of pad renewal is to use VCDS to reset the calipers to account for the thickness of the new pads. This means the ABS module knows the starting point for the new pads, and based on the rotation of the actuator motor each time the parking brakes are applied, it can guesstimate the approximate thickness of the pad remaining.
How they can unevenly, when all four wheels braking same time???
You don't have 8V don't compare it with older 8P
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Yes I would say 60% depends how you drive...I don't think the brakes are "synced" to wear evenly. Fronts do around 75% of the braking, so will wear much faster than the rears. If you've been told different someone is making money out of you needlessly replacing rear pads.
I'd be interested to know re sensors in the rear pads too. I don't think it's that common to have them fitted, and I've always assumed (but never really thought about it) that they were fitted to the fronts only. Perhaps because they're engineered to last the life of a rear disc? When the disc is done, change the pads.
I BET with u that u will change all round pads anyway , so u wanna nice brand new pads at front and even back ..
Ar u sure u not talking ********?? I have quattro and have these but brembo and it clearly says ; Rear Axle, not prepared for wear indicator, excl. wear warning contact : https://www.autodoc.co.uk/ate/8938916
Once I get dash warning for my pads I simply replace all round .. And I know for sure you all will do it and not just rears or fronts..
You have quattro??? I don't think so
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Mine quattro has it differently so Sean was right
It goes to ABS bearing then splits to electric motor for brake and cable going to the front of car underneath
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Rear sensor is nothing to do with fronts.
I unplugged mine when changing them and it brought a warning light up.
Front to back brake pads wear at different rates anyway because of the way the car is set up.
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Because physics, that’s why. All you have to do is google it if you don’t believe me. Front brakes do much more braking. That’s why they are bigger than rears. And on motorcycles why they have twin discs up front and one at the rear. And why many cars still have (more efficient) disc brakes on the front with drums on the back. That’s nothing model or manufacturer specific, it’s science.
I’ll happily replace my front pads 2 or 3 times before doing the rears. The rears get done because they last so long the disc is shot due to corrosion, and who would put worn pads back with a new disc? And Im light on my brakes. My A4 Quattro was still on the original front pads after 5 years and 50,000 miles.
Sensors aren’t wired into ABS
They may share the harness but they do not go to the ABS control unit.
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When I purchased car (in 2019 car year is 2015 so 4 years lasted) obviously discs and pads were rusty. And went for free car check up at audi and in video stated Brake discs and pads need replacing all round so the difference btw fronts and rears were minimal fronts were like 3 or 4mm and rears 5mm So at the end u going to change all...
Sean6211
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T-1000, looks like you have the S3 or RS3 based on the ventilated rear discs. Seems like Audi has included the wired wear sensors for the rear pads on the S3, but it's absent on the A3 models. Or it might have been a running change from PFL to FL. Mine is a PFL so never seen a rear wear sensor.
Yes RS3.
However the comments above about the ‘8V platform’ not having wear sensors aren’t 100% true as the S3/RS3 are an A3 at the end of the day.
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Sean6211
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Yes, you are right. Should be the "A3/S3 8V platform" not having wear sensors. It appears only the RS3 have the wear sensor on the rear left caliper per the service manual:
But in our cases (non RS) what was my point I wanted to say, as you said in post 9 about ABS. So my ABS sensor cable goes to brake motor and then to ECU so that means when brake motor detects pads are too thin so motor will sense it and throw dash warning ?
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A bit of googling suggests yes, the amount of rear pad travel is monitored - possibly by the rear parking brake motor revolutions being counted - and when too many turns are taken the warning pops up. A good reason to follow the proper procedures for replacing rear pads using VCDS. And in my case, to occasionally use the rear parking brake! I mostly rely on the transmission lock (S-Tronic ‘box).
Man u too brainwashed from that google but irony is that I used your google and it led me here
At least I check my facts as far as possible
Here you got, scroll down to the part about sensing rear pad wear
https://www.tomorrowstechnician.com/audi-brake-pad-wear-sensor-operation-and-service/
Here you got, scroll down to the part about sensing rear pad wear
https://www.tomorrowstechnician.com/audi-brake-pad-wear-sensor-operation-and-service/
My question is.........
If Audi employ a wear sensor on the rear of the RS3 then why don’t they use the rear electric motor to ‘count’ the turns thus measuring the pad thickness like your ‘google’ article above suggests ?
Seems like the Audi bean counters missed a trick there don’t you think ?
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If Audi employ a wear sensor on the rear of the RS3 then why don’t they use the rear electric motor to ‘count’ the turns thus measuring the pad thickness like your ‘google’ article above suggests ?
Seems like the Audi bean counters missed a trick there don’t you think ?
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Who knows. Why did Peugeot have at least 6 different clutch cables on the 205? Why does the A3 platform not share the same interior air vents as the A4? Perhaps on the RS3 they do both?
Sean6211
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Possibly because the RS3 being the highest performance variant and likely to see some track use, Audi had decided that the "count the rear caliper motor revolutions" to be not sufficiently accurate to detect pad wear before disc damage occurs?
For example, if the rear pads have 20% pad thickness left and the warning trigger point is say "about" 10%, a single intense track event would blow past that trigger point (since the parking brakes don't get applied during the event). A hard wire wear sensor will trigger the warning message reliably.
Sean6211
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Wow, really? It borders on disappointing that a disrespectful attitude still exists when an input or opinion does not align with your's. It really is a disincentive for others to contribute to this forum, or even to ask questions.
The fact is no one except the engineers at VAG knows why the RS3 has a wear sensor on the rear pad and the S3 and A3 doesn't. Anyone else's opinion, is just that, an opinion.
That's just history.. I do everything by my own facts...At least I check my facts as far as possible
Here you got, scroll down to the part about sensing rear pad wear
https://www.tomorrowstechnician.com/audi-brake-pad-wear-sensor-operation-and-service/
It would be for me stupid not to change all round brake pads
It is like with tyres u change all round not just two or three on quattro system u have to change everything same time otherwise u mess all up with car
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It is just simple german engineer guy decision.. Simply because RS is top of range of all series so it has to have top equipment and best trim
Don't compare series as there is logic reason that higher series will have even better equipment
Mostly unnecessary stuff
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Not quite true as Audi told me that you can change just 2 tyres as long as they are within a few mm of each other.
TX.
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Torsen system is fussy.
Haldex less so, can be 3mm difference according to Elsawin.
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