High pitch, oscillating squeaking noise from rear wheel

[numbahwan]

I've been a frequent lurker since buying and fixing up a 2007 GTI (2.0T FSI) for my fiancee. This month, I've come back to visit her and her new daily driver. To my horror, there is a high pitch, squeaking noise from the driver's side rear wheel (videos below):

The noise oscillates with vehicle speed. It actually is NOT heard when I brake. I don't think that there's been any kind of accident or damage to the vehicle while she's had it. I don't remember hearing it during any of the 3-4 months after I initially bought the car and fixed it up, including swapping out all 4 sets of rotors and brake pads.

Until I can get this car back to my home and on a lift, any ideas what might be causing the sound? Dust shield rubbing against the rotor? Stuck caliper pin? Other?

Thanks in advance for any clues.

[Andy]

Could be dust shield or the pads are worn to the metal marker

[numbahwan]

Update: I've diagnosed the problem. See the small metal notch (red arrow, facing inside surface of rotor) in this picture?


see https://i.imgur.com/dlk0uvM.jpg or https://ibb.co/gVaUoF if not working

It's a part of the mounting/backing plate that's rubbing against the rotor. I've taken a soft mallet and tapped the backing plate inwards (direction of green arrow) so that the rotor sits more evenly in the groove of the backing plate.

Unfortunately, the fix is only temporary. I'm told that the noise is back (although less prominent than before). I'm thinking about going back in to file down the metal notch at the red arrow. Any suggestions? Or thoughts about whether the plate is safe to remove?

[numbahwan]

With the squeaking noise back, this is my second attempt to diagnose and address the root of the problem.

Here is a picture showing that the notch was not the cause but the result of my rotor rubbing against the backing plate (shiny area = rubbed off by rotor):

see http://imgur.com/a/1zzH1 if not working

I figured that the plate will continue to have some mobility, so I thought about filing down each side by 1-2 mm (top side shows area already rubbed off by rotor):

see http://imgur.com/a/MM7z8 if not working

Then, I noticed that the top and bottom (the problematic one on the left, already filed down in this picture) plates are not identical. The top backing plate (on the right) has tabs that minimize its lateral movement when in place:

see http://imgur.com/a/VJBTL if not working

I'm going to order a factory version of this anti-rattle plate, which I think contains the tabs that surround the moving rotor. Gotta be honest -- I'm pretty mad at Wagner for selling me a brake pad kit with mismatched, incorrect hardware.

[Holmsie]

Interesting read and cheers for the pictures. I have a similar sound coming from (I think) rear O/S wheel although not as high pitched as yours. It only happens once warmed up and goes after 10mph upwards, making slow crawling in traffic annoying!...

Wonder if it's the same issue?...