Intermittent vibration while braking at high speeds (50+ mph)

[bakler5]

I replaced all 4 rotors and brake pads about a year ago, just to preface that it *shouldn't* be worn-out brakes or rotors, but for some reason every once in a while my A7 will vibrate slightly while braking at high speeds. Sometimes it is more noticeable than others, but it typically goes away once I drop below 40mph or so. Has anyone experienced this before, or have any suggestions on what might be causing it? I can't recall whether or not it was doing this before I changed brakes/rotors.

[MattyMarkey]

Did it start immediately after replacing? Did you properly bed the brakes after replacement?

At first thought, it sounds like you might have sticky guide pins. Warped rotors will likely vibrate/pulsate all the time, no matter the speed.

[Optimus247]

What kind a mileage is on your Olympic ride ...?

[bakler5]

Did it start immediately after replacing? Did you properly bed the brakes after replacement?

At first thought, it sounds like you might have sticky guide pins. Warped rotors will likely vibrate/pulsate all the time, no matter the speed.

Now that I think about it, I believe it did start relatively quickly after I replaced them, because I remember taking the wheels off to check the carriage bolts to make sure they weren't backing out. It is definitely getting more frequent now though. I did bed them, but honestly, I had never done it before so I have no idea if I did it correctly or not... Guide pins actually make a lot of sense, I will take some time this weekend to inspect those and regrease them. Thanks!

What kind a mileage is on your Olympic ride ...?

I just passed 111k. I bought it late 2021 with about 95k, the only work that I have done since owning is the brakes and rotors. Haven't had any other issues besides this, and it really isn't that bad, just want to catch it before it possibly gets worse.

[Valpo A7]

There is no guarantee that you did not buy a warped or bent rotor when you swapped the pads and rotors. No guarantee that you might have unintentionally got something under the rotor when you tightened it all down. No guarantees that you did not unintentionally warped a pad or a rotor in the break in process as well. Almost always when you feel a vibration under braking conditions it’s a bad pad or a warped rotor. Depending on the brand of rotors they might just be prone to warping.

[bakler5]

There is no guarantee that you did not buy a warped or bent rotor when you swapped the pads and rotors. No guarantee that you might have unintentionally got something under the rotor when you tightened it all down. No guarantees that you did not unintentionally warped a pad or a rotor in the break in process as well. Almost always when you feel a vibration under braking conditions it’s a bad pad or a warped rotor. Depending on the brand of rotors they might just be prone to warping.

I understand that completely. The only thing that has confused me, and led me to believe there isn't anything physically wrong with the pads or rotors is that it doesn't happen every time I drive the car. One day it will be totally fine and brake smoothly, the next day it will pulsate/vibrate while braking at highway speeds. I went with Akebono ceramic pads and Zimmerman rotors, visually the rotors appear to be fine and wearing properly, but I have not taken them off to inspect or anything. I will dig into it this weekend and regrease the guide pins and everything just to be safe.

[MattyMarkey]

I understand that completely. The only thing that has confused me, and led me to believe there isn't anything physically wrong with the pads or rotors is that it doesn't happen every time I drive the car. One day it will be totally fine and brake smoothly, the next day it will pulsate/vibrate while braking at highway speeds. I went with Akebono ceramic pads and Zimmerman rotors, visually the rotors appear to be fine and wearing properly, but I have not taken them off to inspect or anything. I will dig into it this weekend and regrease the guide pins and everything just to be safe.

Knowing that it doesn't happen every day and/or all the time, that could also be a compromised brake line, or master cylinder. Check brake fluid levels too

[Valpo A7]

I have read plenty of times about a collapsed brake hose but only experienced it once. For me the hose passed fluid to allow the brake to apply but then acted like a check valve which did not allow the brake to release. Shook like a mother ******.

[bakler5]

Yeah this doesn't shake bad at all. I don't know how to describe it, but it's not even bad enough to make any noise or anything. At its worst, it's like driving on a crappy road or something.

[Miro_M]

To make sure just indicate your rotors and you will find out for sure . To me you have a bad rotor causing pulsation.

[AudiInMyA7]

I had brakes less than a year old and the above happened - it was warped brakes. If you feel it in your foot when you brake its the fronts, if your ass twerks its the rears


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