Shaking in brake pedal and steering wheel?!

I've noticed when I try to brake a high speeds my brake pedal and steering wheel start to shake. I'm fairly new to BMW and don't know what the problem is. Help?!

Originally Posted by MAGjersey

I've noticed when I try to brake a high speeds my brake pedal and steering wheel start to shake. I'm fairly new to BMW and don't know what the problem is. Help?!

Puzzler:

What is connected to both steering wheel and brake system?

Originally Posted by CALWATERBOY

Puzzler:

What is connected to both steering wheel and brake system?

Honestly couldn't tell you. Not enough knowledge. Whatever's going on is very annoying.

You've got some deposits on the rotor(s), it is causing the brakes to pulsate and in turn, shimmy your steering wheel.

Google: "brake judder"

Originally Posted by thekurgan

You've got some deposits on the rotor(s), it is causing the brakes to pulsate and in turn, shimmy your steering wheel.

Google: "brake judder"

Thank you!! Now just gotta find a way to fix it. Suggestions on that?

Originally Posted by MAGjersey

Thank you!! Now just gotta find a way to fix it. Suggestions on that?

If it is brakes and not your wheels and tires check for uneven wear on the brake rotors/discs, if they have grooves and waves like an old vinyl record you are due for the rotors replacement.

Warped brake rotors likely ..... you must be under OEM maintenance so let the dealer fix this.

yep I vote warped rotors

Doubtful these rotors are warped but rather have a very uneven layer of deposits bonded in areas along the rotor.

From Zeckhausen:

The all-important transfer layer
As stated above, the objective of the bed-in process is to deposit an even layer of brake pad material, or
transfer layer, on the rubbing surface of the rotor disc. Note the emphasis on the word even, as uneven pad
deposits on the rotor face are the number one, and almost exclusive cause of brake judder or vibration.
Let's say that again, just so there is no misunderstanding. Uneven pad deposits on the rotor face are the
number one, and almost exclusive cause of brake judder or vibration.
It only takes a small amount of thickness variation, or TV, in the transfer layer (we're only talking a few ten
thousandths of an inch here) to initiate brake vibration. While the impact of an uneven transfer layer is almost
imperceptible at first, as the pad starts riding the high and low spots, more and more TV will be naturally
generated until the vibration is much more evident. With prolonged exposure, the high spots can become hot
spots and can actually change the metallurgy of the rotor in those areas, creating "hard" spots in the rotor
face that are virtually impossible to remove.


Ref:

http://www.centricparts.com/files/Ce...n%20Theory.pdf

Originally Posted by MAGjersey

Thank you!! Now just gotta find a way to fix it. Suggestions on that?

Did you Google? Try that with no such thing as warped rotors.

Or Bing.

Read like your job depended on it. You might see something about bedding shoes; strong braking at speed.

.

Originally Posted by calwaterboy

did you google? Try that with no such thing as warped rotors.

Or bing.

Read like your job depended on it.

+1

Originally Posted by CALWATERBOY

Puzzler:

What is connected to both steering wheel and brake system?

Originally Posted by MAGjersey

Honestly couldn't tell you. Not enough knowledge. Whatever's going on is very annoying.

All 4 wheels. Your issue is prob at the front wheels. When you brake? Then, with the brakes at the front wheels. Your search should center on juddering front brakes.

Originally Posted by CALWATERBOY

Did you Google? Try that with no such thing as warped rotors.

Or Bing.

Read like your job depended on it. You might see something about bedding shoes; strong braking at speed.

.

Went to the dealer today, and they described it to me as "warped rotors". It was both of the two front ones. Thank god everything is under warranty, didn't cost me a dime. All is good now!

Originally Posted by MAGjersey

Went to the dealer today, and they described it to me as "warped rotors". It was both of the two front ones. Thank god everything is under warranty, didn't cost me a dime. All is good now!

That's the usual cause for steering shake upon braking - although it seems to be relatively uncommon on BMWs.

Glad it's being properly handled under warranty.

Tom

Originally Posted by MAGjersey

Went to the dealer today, and they described it to me as "warped rotors". It was both of the two front ones. Thank god everything is under warranty, didn't cost me a dime. All is good now!

Good deal .... warranty / full maintenance is a wonderful thing on these cars.

As an aside, you can also Google "no such thing as a cryptic message board pompous know it all" ......... but that doesn't mean there isn't one ...........

Dealers always use the term: "warped", because of the runout measured, but highly doubtful and in face is most likely raised areas of deposits. DSX, where are you on this mechanical issue, Bro?

Originally Posted by laser

Warped brake rotors likely ..... you must be under OEM maintenance so let the dealer fix this.

+1 on this. Would be the first thing I would look at if the tires are warn evenly.

Originally Posted by thekurgan

Dealers always use the term: "warped", because of the runout measured, but highly doubtful and in face is most likely raised areas of deposits. DSX, where are you on this mechanical issue, Bro?

Yeah that's pretty much it.

Sometimes brakes are smooth cold; develop judder as they warm. Retorque wheel bolts, prescribed sequence.

Can be suspension problems.

Warped [permanently] rotors? Very unlikely, but a convenient catch-all customers readily accept.

Originally Posted by laser

Good deal .... warranty / full maintenance is a wonderful thing on these cars.

As an aside, you can also Google "no such thing as a cryptic message board pompous know it all" ......... but that doesn't mean there isn't one ...........

Hi Laser -

no such thing as warped rotors....did you try Googling that?

Oh man do I ever want to stay the heck out of this. But I can't. Never had much sense.
I've read all the articles on rotor deposits causing 'judder' or what we in the trade more commonly call brake (pedal) pulsation. It is usually accompanied by rapid but relatively small steering wheel movement in time with the pulsation. Sorry, but my 36 years of experience is that the overwhelming cause is warped rotors which is easily determined with the use of a dial indicator. Pulsation can be perceived beginning at about .002" tir (total indicator reading) and is really objectionable by about .005". The variation can be either out of parrallellism, a sunken spot (it happens!) or warpage. Warpage being the most common cause, and improper tightening of lug bolts being the most common cause of the warpage.

We're starting to see a lot of rotors warped out of the box, especially the lower priced white boxers. Some rotors are improperly stress relieved at the factory and warp after going through a few good hot cycles on the car.

Have I seen deposits cause judder? Absolutely, but I can't remember the last time. In my opinion it's a thing of the past. We used to see 'hard spots' on rotors which are very shiny areas which were raised up over the general surface by a mil or two. They also caused vibration. Whether it's due to new rotor alloys or pad materials I can't say, but hard spots have been gone for decades.

There is no doubt that warpage has caused the greatest incidence of pulsation in my experience, over 99% by far. We remove the rotors, clamp them into a brake lathe (Hoffman, made in Germany) and set a dial indicator on the inner and outer wear surfaces. You can see the dial needles move in tandem in and out. That's warpage. We machine them to factory specs and the pulsation is gone.

Now, bomb me with links to sites that say I'm wrong. I can only speak from experience.

Originally Posted by DSXMachina

We're starting to see a lot of rotors warped out of the box, especially the lower priced white boxers. Some rotors are improperly stress relieved at the factory and warp after going through a few good hot cycles on the car.

There is no doubt that warpage has caused the greatest incidence of pulsation in my experience, over 99% by far. We remove the rotors, clamp them into a brake lathe (Hoffman, made in Germany) and set a dial indicator on the inner and outer wear surfaces. You can see the dial needles move in tandem in and out. That's warpage. We machine them to factory specs and the pulsation is gone.

Maybe I thunk wrongly....could many rotors be warped by repeated uneven heating on the wheel, and be in need o'stress relief? Gotta wonder if cutting 'em would affect that at all....or is the pulse doomed to return?

Cal, only speaking form personal experience ...... can't believe everything you read on the internet ...... ("he's a French model") ..... my 1990 300ZX had chronically warping rotors having been designed too thin and light as a weight saving measure. The dealer would turn them and the pulsating pedal would return. Nissan finally replaced with thicker parts and all was good.

Originally Posted by laser

Cal, only speaking form personal experience ...... can't believe everything you read on the internet ...... ("he's a French model") ..... my 1990 300ZX had chronically warping rotors having been designed too thin and light as a weight saving measure. The dealer would turn them and the pulsating pedal would return. Nissan finally replaced with thicker parts and all was good.

I don't entirely discount the 'deposits' cause of pulsation. It could very well be something common in parts of the country where ambient temperatures are higher or it rains more -or less- or who knows what. I can only speak to what we see in New England (and what I read in my technical and trade magazines). Like road salt corrosion in NH, or dust clogged air filters in TX, or etched paint in acid rain states, different things attack cars in different parts of the country.

You've really got to heat the brakes up to get enough deposit to cause judder...like a day of hard tracking. Warping due to poor lug bolt torquing is most likely. I always retorque the lug bolts after a service...they are slapped on with an impact wrench. I had some winter wheels put on with a 138 ft.lb loosening torque one time! The pay system for BMW techs offers them no incentive to carefully check torque values on wheels.

Originally Posted by ///M-ratedE90

You've really got to heat the brakes up to get enough deposit to cause judder...like a day of hard tracking. Warping due to poor lug bolt torquing is most likely. I always retorque the lug bolts after a service...they are slapped on with an impact wrench. I had some winter wheels put on with a 138 ft.lb loosening torque one time! The pay system for BMW techs offers them no incentive to carefully check torque values on wheels.

I've also experienced deposits from folks not bedding them in properly, as in the hot summer, exiting freeways and leaving the foot on the brake pedal for extended periods. The few times I've had some judder I just popped on a set of new pads and did a re-bed and seemingly "ground" off the old deposits. Agree on the wheel bolt torque.