Steering wheel shake when braking

[geeman789]

Originally Posted by Quattro Pete
Originally Posted by jeepman3071
If you replace the brakes and it doesn't fix it, then it is likely front control arm bushings or another front suspension component.

One thing the shop noted the last time I was there about 6 months ago was that "Front shock bump stops are deteriorating." Would that have anything to do with what I'm experiencing?


No. Bump stops are a rubber component located on the strut / shock shaft. They limit max. travel and provide cushion when the strut " bottoms ... " out over large sharp bumps. They will not create a shimmy or vibration under any condition.

99 % of the time a brake shimmy / shudder felt thru the steering wheel is caused by uneven pad deposits on the rotors, or uneven wear on the rotor caused by overheating.
This can be caused by something as simple as coming to a firm stop from medium or high speeds, and then keeping your foot on the brake pedal for the minute or so the light is red. The pads are screaming hot, and now being pressed against one part of the rotor, super heating it, and the pads.

New rotors will likely fix it, as would a light resurface / turning. Also, a change to a cheap metallic pad and some hard stops can scrub the rotors of any pad deposits.

With almost all modern cars being automatics, it seems like brake shudder is inevitable at some point in the brakes life.

 

[geeman789]

Originally Posted by jeepman3071


... Sometimes you can determine if the control arm bushing are bad by turning the wheel all the way out, then using your foot to quickly push on the tire backward to see if it moves. If there is a lot of movement, the bushings are bad. The exact symptoms you describe were on a friend's E90. Replaced the lower front control arms from FCP Euro and the car is like new again.



I had a bad control arm bushing on a previous car. The car would turn a little, then suddenly turn a lot. Car rarely tracked straight, always needing steering correction back and forth. It was scary to drive at high speed.

 

[Quattro Pete]

Originally Posted by geeman789
New rotors will likely fix it, as would a light resurface / turning. Also, a change to a cheap metallic pad and some hard stops can scrub the rotors of any pad deposits.

With almost all modern cars being automatics, it seems like brake shudder is inevitable at some point in the brakes life.

Current pads are Akebono Euro, which are ceramic, I believe.

It's a manual trans, but I still typically hold the brake pedal in at a traffic light to prevent it from rolling.

 

[The Critic]

Originally Posted by Quattro Pete
Originally Posted by Vaca
I had that issue on my e60, a 2004 530i, a couple years ago. The steering wheel shake was most noticeable when braking at high speed or with higher pedal force.

In my case, the shake is more noticeable when applying lighter pedal force. When braking hard, it's less noticeable.

Check your thrust arm bushings first.

Originally Posted by Quattro Pete
Originally Posted by geeman789
New rotors will likely fix it, as would a light resurface / turning. Also, a change to a cheap metallic pad and some hard stops can scrub the rotors of any pad deposits.

With almost all modern cars being automatics, it seems like brake shudder is inevitable at some point in the brakes life.

Current pads are Akebono Euro, which are ceramic, I believe.

It's a manual trans, but I still typically hold the brake pedal in at a traffic light to prevent it from rolling.

Originally Posted by Rand
could be pad deposits on the rotors.

"Ceramic pads" in Euro cars, or "ceramic" pads in general, tend to have pulsation issues caused by uneven pad deposits. Once the deposits start forming it is almost impossible to remove them without machining or replacing the rotors. Most of these pads are not aggressive enough to wear away the deposits even during a bed-in.

 

[Quattro Pete]

Originally Posted by The Critic
Check your thrust arm bushings first.
Yeah, I had those replaced before. The car lacks straight line stability when these bushings are shot, so I know that's not it this time around.


Quote
"Ceramic pads" in Euro cars, or "ceramic" pads in general, tend to have pulsation issues caused by uneven pad deposits. Once the deposits start forming it is almost impossible to remove them without machining or replacing the rotors. Most of these pads are not aggressive enough to wear away the deposits even during a bed-in.
Should I try to find non-ceramic pads next time around? Are the OEM pads ceramic?

 

[Vaca]

Originally Posted by Quattro Pete
Are the OEM pads ceramic?


I don't think the original pads were ceramic. My 2004 530i had the original pads on it when I bought it back in 2007 or 2008 and they were semi-metallic. If memory serves, they were Jurid pads. Interestingly I just changed the original rear pads a month ago with 240,000 miles on them. I could not read the manufacturer stamping on them though.

 

[Quattro Pete]

Originally Posted by Vaca
If memory serves, they were Jurid pads.

Yup, I think OEM is either ATE or Jurid. Just not sure of their composition.

 

[Aredeeem]

My experience is warped rotors. Especially during high speed braking(such as negotiating a long exit ramp from an interstate). In Jersey you can forget about getting them "turned." Its just "you need new rotors." If you could find a retired blacksmith..maybe.

 

[The Critic]

Originally Posted by Quattro Pete
Should I try to find non-ceramic pads next time around? Are the OEM pads ceramic?

Not on BMW's from that vintage. Some of the newest Euro cars are switching to a different type of material that are causing them to develop the same pulsation issues found on Asian/domestic vehicles. But BMW's from that era still used the aggressive metallic pads.

I would pick Jurid pads and Zimmerman rotors for your car.

https://www.rmeuropean.com/Products/34116761252-MFG49-V373.aspx
https://www.rmeuropean.com/Products/34116767059-MFG359-V373.aspx

 

[slacktide_bitog]

Rotors, uneven pad deposits, or even uneven torque on the lug nuts (which is why I HATE shops that use the air gun: excessive, uneven torque on the wheels)

 

[Chris142]

Some people will say that its pad deposits on the rotors. I have never seen that in my 37 years of working on cars and brakes so until I see it myself I say that's hogwash.

The rotors may be bent,warped or have uneven thickness.

 

[LeakySeals]

I think its more often uneven pad material distribution vs a warped rotor if...

- you have no rust or debris between the rotor and the hub.
- you follow proper torque procedure.
- you have no known suspension or drivetrain issues

I've had rotors with unacceptable lateral runout. But there is usually a reason other than the steel actually "warping". Like..

- A wheel bearing/hub going bad.
- Rust causing the rotor not to be flush with the hub.
- Not following proper torque procedure.

These problems create uneven wear on the rotor surface also known as parallelism. Not to be confused with "warped".

 

[Trav]

Be sure to make sure the back of the wheels are clean, any corrosion on the wheels or hub can cause this also when braking and not necessarily while driving.

 

[Gebo]

Originally Posted by Trav
Be sure to make sure the back of the wheels are clean, any corrosion on the wheels or hub can cause this also when braking and not necessarily while driving.


You scare me. You beat me to it. 1/1000 off in center of hub is greatly magnified by the time you get to the outside of the hub.

Generally speaking, warped rotors are more noticed under normal braking. Light braking and hard breaking is normally less noticeable.