Steering vibration under braking

[squire7@me.com]

Hi

I’ve just a 1m yesterday, Absolutely loving the car. Just one thing before selling the car to me my friend did have the brakes checked due to a slight vibration coming through the steering wheel. He has owned for a year and only driven it for around 1500miles. Has anyone else experienced this issue before? The garage did take the brakes off to check for warping, to only confirm the discs aren’t warped/pads are fine. The tyres are 6yrs old on Michelin cup 2’s.

Could it be it hasn’t been used enough? He hasn’t tracked at all, due to have other cars to track.

Thanks

[nachob]

Originally Posted by squire7@me.com

Hi

I've just a 1m yesterday, Absolutely loving the car. Just one thing before selling the car to me my friend did have the brakes checked due to a slight vibration coming through the steering wheel. He has owned for a year and only driven it for around 1500miles. Has anyone else experienced this issue before? The garage did take the brakes off to check for warping, to only confirm the discs aren't warped/pads are fine. The tyres are 6yrs old on Michelin cup 2's.

Could it be it hasn't been used enough? He hasn't tracked at all, due to have other cars to track.

Thanks

If you read the manual it states that these are high performance brakes that need periodic heavy application and they will form some sort of corrosion from just sitting around especially in damp environments or being washed and out away with rust on brakes. I had the same issue and the dealer called it garage rot. I replaced pads and rotors at that time. That was five years ago. Ever since I always drive the car immediately after washing and brake hard to take the rust layer off before storing in the garage. San Diego is also not as humid and when I drive I always try to get a hard stop in or two. I have not had the issue since. These brakes will corrode just sitting around and once corroded i don't think you can take it out. I believe it's in the supplemental manual that references the brakes. I posted that before I'll see if I can find it. If the rotors are fairly new you might try turning them and new pads since they are about $300 each

Here is a link to the manual:


https://www.1addicts.com/forums/atta...tps=1445515421

It's in page 25 under brake corrosion

[squire7@me.com]

Thanks, go news it will be my daily. Hopefully with some heavy braking it will go away.

[nachob]

Originally Posted by squire7@me.com

Thanks, go news it will be my daily. Hopefully with some heavy braking it will go away.

I also make sure to always take the rust off the brakes after washing and storing. Lot of people wash the car before putting the car cover on and leave the rust on the disks. I take the extra step of taking it for a couple of hard stops to take off rust from the rotors always after a wash.

Also when I take it out, I always add one or two hard stops.

Since I do both of these, I'm not sure if one is the magic step for sure, but both have worked for me.

5 years now with same brakes and no problems following these two steps.

[nachob]

Originally Posted by squire7@me.com

Thanks, go news it will be my daily. Hopefully with some heavy braking it will go away.

I don't think it will but can't hurt to try.

Your best bet is to get the front rotors turned if they are relatively new and throw some new pads then drive and store accordingly.

[///BYU]

Congrats on your 1M purchase and welcome!

In addition to what has already been mentioned, you might want to check the hub/rotor mounting surface to make sure it's clean and even. I use a dial indicator to check the hub for runout before installing the rotor. After installing the rotor I then check the rotor for runout. Brake judder can be caused by runout at the hub, at the rotor, and the combination of the hub and rotor (either because the mounting surface isn't perfect or the cumulative effect of runout at both the hub and rotor). Sometimes rotating the rotor 180 degrees on the hub can make a difference, though I can't remember if that's possible with the rotor set screws on our car (I'm at work right now). Uneven brake pad material could be a cause (but it sounds like the shop said the pads are good), as could corrosion, as nachob mentioned.

What you want is no runout (no side to side wobble as the rotor turns -- you need a dial indicator to see this) and a nice transfer layer of brake pad material on the rotor. Maximum braking happens when the brake pad comes into contact with brake pad material deposited on the rotor (not the rotor itself). That's why bedding in your brakes properly helps -- to deposit that friction material layer.

Here's something on bedding in that might be useful (pdf attached below). I don't think the exact process matters as much as doing something to create an even transfer layer of brake pad material on the rotor. I looked at several brake bedding in procedures and based on those, came up with my own formula that approximates the one mentioned in the attached file. Basically, you make a several stops from 60 mph / 100 kph or thereabouts to almost zero (don't come to a full stop) and after that you drive long enough without stopping to let everything cool down. Not only is it good for your braking performance, it's fun, too.

In endurance racing these quick connect braking systems have already been run in before the race so they're ready to go as soon as they're installed. They replace calipers, pads, and rotors in under a minute (skip to 2:15 in the video).

[///BYU]

Here's another good resource on bedding in brakes:

https://www.tirerack.com/tires/tiret....jsp?techid=85

[ayao]

I'll add this tech video from Essex on bedding as well.

[squire7@me.com]

Thanks everyone

[a4nut]

My e90 had a vibration under braking, and the solution was new control arm bushings. Completely solved the issue, so if "cleaning" the rotors doesn't solve it you may check those.

[nachob]

Originally Posted by a4nut

My e90 had a vibration under braking, and the solution was new control arm bushings. Completely solved the issue, so if "cleaning" the rotors doesn't solve it you may check those.

Yes that can be but
I think the brake rotors especially for cars that sit a long time has a higher likelihood of being the cause so if turning or replacing the rotors doesn't solve it then someone can look down the list of lower probability items. Most 1Ms are lower mileage and sit for long periods of time not to mention that BMW even noted rotor corrosion in their manual and it is something I have experienced. The rotor not warped but corroded from winter parking and causing vibration under braking. I would just hate to see someone replacing bushings without first checking out the most obvious thing.