Braking Vibration -- I'm at a loss

[anotero]

I am in search of advice.

I experience a vibration in what feels like the chassis of my GTI upon braking (high-medium to strong brake pedal depression). The vibration is not overly strong and is accompanied by a strong deep buzz; no vibration in steering wheel or brake pedal (at least none that I can speak of). Vibration occurs at around 50-55+ mph when braking from 65mph to 80mph (have not tested braking at higher speeds). The vibration does not continue until stopping, instead goes away after the speed drops by about 10mph after onset.

Here's what I've done: had my front brakes changed (calipers, carriers, rotors, pads, brake fluid), had my rear brakes changed (rotors and pads). Same result as with previous brakes all around. I did not brake hard with new brakes, however my front rotors have multiple concentric rings that are similar to heat rings. At the same time I highly doubt that is the cause of the vibration -- my rear rotors that I took off looked like ass, but the problem persists with new rear rotors, which are in a pristine perfect condition. Front wheel bearings seem to be fine (I tested by moving the wheels left-right and up-down; no sounds, no squeaks, no rattles).

What are possible causes of this vibration and what are ways to diagnose the problem? Thanks in advance.

 

[replicate]

So the vibration is the same before and after you replaced all the brakes?
When did it start?
What other work is done to the car?
Any recent servicing or mods just prior?
Had you taken the disc off prior to experiencing the vibration?

Wheel bearings?
Run out, but if it vibrated as soon as you put the new discs on then I doubt it.

 

[anotero]

So the vibration is the same before and after you replaced all the brakes?
When did it start?
What other work is done to the car?
Any recent servicing or mods just prior?
Had you taken the disc off prior to experiencing the vibration?

Wheel bearings?
Run out, but if it vibrated as soon as you put the new discs on then I doubt it.

Same vibration. Maybe a little reduced after new rotors, but not significantly.
Started randomly at around 40k miles. Currently have lowering springs and aftermarket shocks, vibration started before.
No mods just prior.
I got new front rotors some thousands of miles before the vibration started, but there's no direction connection. Vibration persists with a second set of new front rotors.

I checked the hub assembly today for wobble visually (1st gear up to 2k RPM on jack stands), seems fine. I did notice what looked like an aberration in the right axle, maybe it's bent, but still very hard to tell. And why have this vibration at that magical number of 55mph? Man, this is going to get the best of me.

 

[replicate]

Did you perfectly clean the hub surface down before fitting the discs? As in sanded them down? Does sound like runnout now. Take it to a shop and have them measure for runnout.

 

[anotero]

Did you perfectly clean the hub surface down before fitting the discs? As in sanded them down? Does sound like runnout now. Take it to a shop and have them measure for runnout.

Yes, i cleaned them. The question is: why would runout all of a sudden appear the way my vibration did?

 

[anotero]

I had a buddy of mine (mechanic at Audi) drive the car today. The vibration is strongest on the front left. Considering I have 61k miles on the car, most of which are over shitty California roads, I will replace the left wheel bearing. I hope that fixes the issue.

 

[cb1111]

What wheels do you have? Any spacers or hub centric rings?

 

[anotero]

What wheels do you have? Any spacers or hub centric rings?

Wheels have been ruled out: running aftermarket now, had same problem back when I had OEM Austins on.

 

[Engineer90]

Wheels have been ruled out: running aftermarket now, had same problem back when I had OEM Austins on.

You mentioned the Cali roads are garbage. Do you remember hitting a pothole hard?

I'm having the same issue as you.

I'm starting to this it's the wheel bearing, I did hit a couple pot holes real hard a few weeks back.

 

[cb1111]

Wheel, brakes ruled out. While I wouldn't have lowered the car with a weird issue, it seems that you can rule that out as well.

That leaves something worn that you didn't change on the suspension or the wheel bearings.

Go to a good suspension shop and have them check everything.

Since you've ruled out brakes as the culprit, you need to ask yourself "what else moves or has additional stress when you apply the brakes?"

I had a similar problem years ago on a Rover and asked myself "ball joints, bearings, A arms, shocks?" It turned out in my case to be a bent suspension bit made more obvious by a bad alignment. I actually liked that Rover 3500 VandenPlas even though it had the usual English reliability

 

[anotero]

You mentioned the Cali roads are garbage. Do you remember hitting a pothole hard?

I'm having the same issue as you.

I'm starting to this it's the wheel bearing, I did hit a couple pot holes real hard a few weeks back.

That's one thing i don't remember doing. I am very attentive to the road immediately in front of me, so no potholes that i can remember. and i check my wheels regularly for any signs of bending. Then again every time i'm on the 405 in LA, i feel like i'm driving through one large pothole -- it's like a washer board.

I tried the simple wheel bearing test -- pushing and pulling the wheels up down and side to side. They do not budge. But then again, who knows? The front suspension consists of so many interdependent components that god knows what's wrong.

 

[anotero]

Wheel, brakes ruled out. While I wouldn't have lowered the car with a weird issue, it seems that you can rule that out as well.

That leaves something worn that you didn't change on the suspension or the wheel bearings.

Go to a good suspension shop and have them check everything.

Since you've ruled out brakes as the culprit, you need to ask yourself "what else moves or has additional stress when you apply the brakes?"

I had a similar problem years ago on a Rover and asked myself "ball joints, bearings, A arms, shocks?" It turned out in my case to be a bent suspension bit made more obvious by a bad alignment. I actually liked that Rover 3500 VandenPlas even though it had the usual English reliability

I'm considering ball joints, wheel bearings, and tie rod ends. Now seeing a bent component is going to be much more difficult. I'm going to bring it in to the mechanic that did my springs and new shocks/struts and have him inspect the entire front end. Although throwing $180 at a replacement hub/wheel bearing assembly is VERY tempting right now.

 

[cb1111]

I'm considering ball joints, wheel bearings, and tie rod ends. Now seeing a bent component is going to be much more difficult. I'm going to bring it in to the mechanic that did my springs and new shocks/struts and have him inspect the entire front end. Although throwing $180 at a replacement hub/wheel bearing assembly is VERY tempting right now.

A good suspension shop should be able to find the problem.

You could always try the old school method. Put the car on a lift with somebody in the driver's seat. Step on the brakes and have the other tech see what moves on the suspension.

All the stuff you learn at an Army Auto Hobby Shop - check wheel balance with a piece of chalk, measure alignment with string etc.

 

[anotero]

So I just got back from the garage because I'm OCD and decided to test the wheel bearings again, this time with the wheels on (for better leverage). The wheels do budge when I pull them side to side, but don't wobble, and they do resist lateral motion greatly. Not a lot and with some force on my part. I also hear a slight clicking sound when I pull them side to side. The wheel play occurs on both sides. Once again, it is not significant and requires me to apply a discernible amount of force. Also I tried spinning the wheels (the car's in Park, for what that's worth). I can hear the bearings "rustle" -- make a typical ball bearing sound. I do not know whether it is supposed to be easily discernible, but it is in my case -- loud and clear.

 

[anotero]

A good suspension shop should be able to find the problem.

You could always try the old school method. Put the car on a lift with somebody in the driver's seat. Step on the brakes and have the other tech see what moves on the suspension.

All the stuff you learn at an Army Auto Hobby Shop - check wheel balance with a piece of chalk, measure alignment with string etc.

Considering this is my first vehicle and I've started doing work on it myself somewhat recently, it turns out I'm somewhat mechanically inclined. The main problem is the absence of a lift and my living in the middle of nowhere. All I do is on simple jack stands with very limited clearance for my head to fit under the car. But I'm getting there.