I think I have a warped brake rotor. Thoughts?

[benstalls]

Hey all, I have a 2013 GTI with 69,936 miles that has developed an unpleasant noise.

To start, the car definitely needs new brake pads. I am also replacing the rotors, along with new brake hardware (carrier bolts, slide pins, caliper clips, and the like). I have the stuff, just waiting until work calms down and I have time (hopefully next week).

The grinding noise developed not long after I started to hear the wear indicator on the brakes. The noise is most prominent after approximately 20 minutes of driving and regular braking, and I can hear it best at around 20 MPH. It doesn't get much louder with speed; it simply diminishes. I cannot hear it at all when driving it after it sits overnight or while I'm at work.

Today, after work, I took some time to look at it, shaking both of the front wheels side to side to see if I could feel any wheel bearing play. There wasn't any (not definitive, but it's something), and there is no shaking in the steering or unpredictable steering while driving either. I then removed the wheels to see if a rock might have gotten stuck between the dust shield and rotor, but I couldn't see anything. What concerned me was that when I spun the driver's side rotor by hand, I could feel it becoming harder to move at a certain spot. I could hear it while spinning it with the wheel on, too, but with the extra weight of the wheel, the feeling was not as profound. This suggests a warped rotor to me. I am pretty certain that the rotors are original to this car, as they have developed a good amount of rust on the lip; they also have a decent amount of streaking.

Here is a video showing you where the rotor seems to get stuck. I took this video about 30 minutes after parking it. Any input is very appreciated!

 

[benstalls]

I believe I put this in the wrong sub-forum... It belongs in General VW/Audi repair, doesn't it? My apologies!

 

[Uwe]

I believe I put this in the wrong sub-forum... It belongs in General VW/Audi repair, doesn't it? My apologies!

I've moved it for you.

-Uwe-

 

[Uwe]

This suggests a warped rotor to me.

I would think the proper tool to confirm rotor warping is a dial gauge -- something like this:

Qnkaa Dial Indicator with Magnetic Base Holder Fine Adjustable Long Arm 0-1" Magnetic Dial Indicator Professional Dial Gauge 0.001": Amazon.com: Industrial & Scientific

Qnkaa Dial Indicator with Magnetic Base Holder Fine Adjustable Long Arm 0-1" Magnetic Dial Indicator Professional Dial Gauge 0.001": Amazon.com: Industrial & Scientific

www.amazon.com

However, if you're doing a complete brake job:

the car definitely needs new brake pads. I am also replacing the rotors, along with new brake hardware (carrier bolts, slide pins, caliper clips, and the like).

It may not be worthwhile to spend $40 more on such a tool.

-Uwe-

 

[BlueR32]

When the pads/rotors are well worn you can experience all sorts of weird behavior IME. As long as you have all new components I would install them and expect the issues to be resolved. With most newer cars including VWs it's almost mandatory to replace the rotors as they wear a lot over the life of a set or two of brake pads. The rotors can also warp or the calipers can stick and drag on one side of the rotor.

Report back either way to help other folks who might be experiencing similar issues.

 

[Dr Sheldon]

The noise is most prominent after approximately 20 minutes of driving and regular braking, and I can hear it best at around 20 MPH.

A warped Brake Disc (rotor) will not produce the noise you write about !!

A warped disc can be diagnosed by driving the car and applying the brakes - it will cause judder.

 

[Dukedesmo]

A warped Brake Disc (rotor) will not produce the noise you write about !!

A warped disc can be diagnosed by driving the car and applying the brakes - it will cause judder.

Indeed, my S4 had such a judder from the front under braking, especially light braking.

The discs and pads had plenty of material on them, having not done many miles but I measured 0.15 & 0.11mm of runout on the front discs (I understand up to 0.05mm is considered OK?).

Replacing them and new pads completely solved the problem.

 

[Dr Sheldon]

(I understand up to 0.05mm is considered OK?).

Not sure about the figure but if there is judder then there will be no need to make a measurement, Cheap discs and/or those that have been overheated suffer from warping.

As you say, very noticeable at light braking.

The grinding noise developed not long after I started to hear the wear indicator on the brakes.

A warped Disc will not create a Grinding noise ! However OP is doing a Brake Overall and should look for and find the reason for the grinding.

Could be as simple as a stone trapped in there.

 

[benstalls]

Thank you all for your help. Today, I swapped out my front pads and rotors, which allowed me to pinpoint the source of the noise.

It turns out I was looking in the wrong place completely. After completing the job and taking a test drive, I listened for any noises, and the grinding was still present. However, without the noise of the worn front pads, I was able to hear the noise coming from the back.

I went to an empty, flat parking lot and rolled the car by hand, keeping it in neutral. It did not take long before I could hear the rear-left wheel making noise, even at the slow speed at which I was pushing it. I took a look at the rotor, and it was obvious, there were some uneven wear patterns. Jacking the car up and spinning the wheel by hand reproduced the same noise I was hearing.

You can see the streaking towards the center. None of the other rotors exhibited this. I'm fairly confident this is my issue.


I'm probably going to let my mechanic handle this; the rear caliper carrier bolts are incredibly difficult to remove without a lift, and there isn't enough room for my impact gun either. I have all the parts on hand, so I'll call on Monday to set an appointment. I was in there replacing a wheel speed sensor about a week and a half ago; I probably managed to lodge something in there...

 

[Dr Sheldon]

I'm probably going to let my mechanic handle this; the rear caliper carrier bolts are incredibly difficult to remove

You do ot need to remove them !! The Caliper CARRIER bolts !!

Remove the brake pads and all will be revealed !

 

[Dr Sheldon]

without the noise of the worn front pads,

You kidding us here ?

What noise do worn brake pads make ? Where the front pads metal to metal ??

 

[Dr Sheldon]

Where the front pads metal to metal ??

Were the brake pads .............. Typo !

 

[benstalls]

You do ot need to remove them !! The Caliper CARRIER bolts !!

I have tried before, but the rotor is too large and cannot slide between the hub and carrier. From what I've seen, this appears to be a flaw unique to the Mk6 GTI. I have replaced the rotors on my friend's old Mk6 Golf; those were small enough not to require removing the carrier.

What noise do worn brake pads make ? Where the front pads metal to metal ??

The noise I'm referring to was the wear indicator. For me at least, it was loud and distracting enough to make it hard to hear much else. Perhaps if I had tried a bit harder and paid closer attention, I would have noticed, but I didn't (I'm sorry!). They were not metal to metal but were all due for replacement anyway.

 

[BlueR32]

Thank you all for your help. Today, I swapped out my front pads and rotors, which allowed me to pinpoint the source of the noise.

It turns out I was looking in the wrong place completely. After completing the job and taking a test drive, I listened for any noises, and the grinding was still present. However, without the noise of the worn front pads, I was able to hear the noise coming from the back.

I went to an empty, flat parking lot and rolled the car by hand, keeping it in neutral. It did not take long before I could hear the rear-left wheel making noise, even at the slow speed at which I was pushing it. I took a look at the rotor, and it was obvious, there were some uneven wear patterns. Jacking the car up and spinning the wheel by hand reproduced the same noise I was hearing.

You can see the streaking towards the center. None of the other rotors exhibited this. I'm fairly confident this is my issue.
View attachment 3764

I'm probably going to let my mechanic handle this; the rear caliper carrier bolts are incredibly difficult to remove without a lift, and there isn't enough room for my impact gun either. I have all the parts on hand, so I'll call on Monday to set an appointment. I was in there replacing a wheel speed sensor about a week and a half ago; I probably managed to lodge something in there...

I can't see the streaking but IME it's very common for the rear calipers to stick more than the front calipers. Both the slides and the pistons tend to stick. The rear carrier bolts are definitely a PITA to remove. I wouldn't consider them a defect, just poor planning. While some of the things that designers do appear unbelievable dumb in general they are doing what they are told to do for some specific reason. When you can't change the oil filter without jacking the engine up off it's mounts - THAT is a defect.

 

[benstalls]

I can't see the streaking but IME it's very common for the rear calipers to stick more than the front calipers. Both the slides and the pistons tend to stick. The rear carrier bolts are definitely a PITA to remove. I wouldn't consider them a defect, just poor planning. While some of the things that designers do appear unbelievable dumb in general they are doing what they are told to do for some specific reason. When you can't change the oil filter without jacking the engine up off it's mounts - THAT is a defect.

Maybe I'm not using the right terminology, a portion of the rotor is noticably lighter towards the center on the wheel making the noise. The other side has no such thing. Maybe a better term would be an uneven wear pattern.

You're right, though, just bad planning. My old Ford Taurus burried the filter under the exhaust manifold and right next to the starter. First time I changed the oil, I managed to bridge a battery post with the filter and put a hole in it. I was lucky that I didn't burn myself lol. I shouldn't have to disconnect the battery for an oil change...

 

[Dr Sheldon]

I have tried before, but the rotor is too large and cannot slide between the hub and carrier.

What I meant was:

You will not have to remove the CARRIER bolts to remove and inspect the Pads. Just the Slider bolts ?

Yes to remove the Rotors you may have to remove the "Carrier" bolts. Not on all cars but a fair percentage.

The noise I'm referring to was the wear indicator. For me at least, it was loud and distracting enough to make it hard to hear much else.

On a VW ??

I have always known them to have an "Electric" Dash Indicator as opposed to an acoustic wear indicator, a metal squealer strip that touches the disc and makes a horrendous noise ?

Like this



Does the 2013 not have a Brake Pad Warning Light on the dash but this type ?

Pardon my ignorance but I have done very little "service" work this century !

 

[benstalls]

What I meant was:

You will not have to remove the CARRIER bolts to remove and inspect the Pads. Just the Slider bolts ?

Yes to remove the Rotors you may have to remove the "Carrier" bolts. Not on all cars but a fair percentage.



On a VW ??

I have always known them to have an "Electric" Dash Indicator as opposed to an acoustic wear indicator, a metal squealer strip that touches the disc and makes a horrendous noise ?

Like this

View attachment 3765

Does the 2013 not have a Brake Pad Warning Light on the dash but this type ?

Pardon my ignorance but I have done very little "service" work this century !

You're right, it would just be the slide pins to inspect the pads. I'm going to remove the pads today and inspect. I was saying that I was getting the rotor replaced anyway which is why I said I'd let my mechanic handle it.

As for the wear indicator, while it does have an electronic dash indicator the pads weren't thin enough to activate it. However, there was an audible screech coming from them while braking like a traditional wear indicator that has since subsided after putting new pads on.

Perhaps it uses both? I've seen plenty of drivers ignore the screech, so maybe the dash is supposed to act as a scarier warning?

 

[Dr Sheldon]

Perhaps it uses both?

Not likely - VAG would not spend / waste that money.

I would bet it will be one or the other or none at all.

Anyway you tell me please - I am some thousands of miles further from the car than you are !