[sp330i]

On the way to work this morning, something very strange happened. Upon my first medium pressure application of my brakes at about 40 miles an hour, my steering wheel begins vibrating back and forth profusely (like an old truck with out of blanced wheels) and I feel slight pulsation in the pedal.

Here is the interesting part, upon the next application of my brakes and continued driving, the problem dissappears. My rotors don't appear to be warped and my wheels don't appear to be out of balance because I notice no other significant steering wheel vibration (other than a very slight out of balance condition induced by the dealer at my last visit) and no pulsation in the brake pedal.

I think I need to get my steering linkage and front suspension checked. I only have about 16k on the car and the steering retro was performed last November.

How about some expert opinions here.

 

[webguy330i]

Definitely doesn't sound like the brakes, unless you regularly slap a lop-sided splatter of dry dog doo on your rotors just for fun! That's about all I can think of that would cause the one-time-wheel-shimmy you explained.

It sounds much more like a mechanical defect somewhere, like something just went nuts! BTW I'm no expert.

 

[ERK]

Maybe you just had some dirt on the rotors and the first braking "cleaned" them. A good tap on the brakes from 40 mph to 0 will clean them off. I think someone around here called that the Bavarian Tune Up (or is that when you decarbonize by taking it to the redline?).

 

[webguy330i]

Maybe you just had some dirt on the rotors and the first braking "cleaned" them. A good tap on the brakes from 40 mph to 0 will clean them off. I think someone around here called that the Bavarian Tune Up (or is that when you decarbonize by taking it to the redline?).

I think that's the redline technique, and anyhow dirt/sand/oxidation wouldn't cause such a noticable wheel shake.

 

[sp330i]

I think that's the redline technique, and anyhow dirt/sand/oxidation wouldn't cause such a noticable wheel shake.

I agree. My 3 is garage kept and my streets are clean. Didn't see any dog doo either. :dunno:

 

[ERK]

anyhow dirt/sand/oxidation wouldn't cause such a noticable wheel shake.

Prob. not. But it went away so that's all I could think of.

How about some expert opinions here.

I need to read more carefully.

 

[DougDogs]

I have often wondered how the DCS system might try to respond to a problem like "one caliper piston hanging up"

You say you hit the brakes pretty hard...I wonder if one of your brake piston's didn't engage the pads... I wonder if the brake system would over-modulate to try to correct for this???

 

[Adrian 330Ci'01]

Here is the interesting part, upon the next application of my brakes and continued driving, the problem dissappears. My rotors don't appear to be warped and my wheels don't appear to be out of balance because I notice no other significant steering wheel vibration (other than a very slight out of balance condition induced by the dealer at my last visit) and no pulsation in the brake pedal.

So... is it possible that you hit a patch of road with really messed up camber? There is a stretch of road near Toronto that I go over regularly that is so nasty (in combination with my fat low profile tires) that it would put me into wall if I wasn't holding on with both hands. It pulls me side to side really violently. If I happened to be hitting the brakes at the time I could see the confusion.

Were you on a piece of road you were familiar with?

A.

 

[PunchIt]

Tramling?

My first thought would be that it was cause by uneven road. I've had all sorts of brake/stearing shutters, pulls, vibrations that I thought were caused by warped rotors, out of balance wheels, and bald tires.

When I re-create the same driving conditions (speed, brake pressure, etc...) on a nice new, flat slap of asphalt I get nothing, nada, zip..... the car drives straight, brakes straight and has no vibration or shimmy.

My guess is that until you can make the car act weird on a totally level, clean peice of road; don't run to the dealer.

my $.02

DM

 

[webguy330i]

Re: Tramling?

... until you can make the car act weird on a totally level, clean peice of road; don't run to the dealer.

Some time-saving advice here folks! :thumbup:

 

[PunchIt]

Re: Tramling?

My guess is that until you can make the car act weird on a totally level, clean peice of road; don't run to the dealer.

DM

Ok, so I can't spell.

 

[rwg]

I had a very similar problem to this with my snow tires. It was intermittent, but happened regularly while braking on off ramps from the highway. I had the wheel re-balanced and the problem went away.

 

[325xi-SteelGray]

Since you said it only happened once and I am not an expert, I only have this to contribute. I too had the steering retrofit and have been having a problem with brush control arms in the steering, which causes the "shimmy shake." I am going on my 3rd... Keep us posted, especially if it turns out to be a control arm...

I would err on the side of caution and go to the dealer, especially if they are nice to you, which is always a bonus!

 

[sp330i]

Thanks to everyone for your insight and suggstions. I think I'll just keep an eye on it.

I have an appt with the dealer on 8/13 so if it happens again, I'll have them look at it then.

 

[PunchIt]

a problem with brush control arms in the steering, which causes the "shimmy shake."

JR,

Do you mean control arm bushing?

 

[325xi-SteelGray]

Do you mean control arm bushing?

That sounds better! I didn't exactly look at my invoice to get the correct terminology! Whatever it is, I think it also causes the shimmy shake and isn't too cool! I can't get it all right, now can I?