Steering wheel shake when stopping

[JHZR2]

Hi,

I installed Zimmerman cross drilled rotors and textar pads on the front of my 91 318i many years ago, after I refinished a set of basket weave alloys for it. Knew less than I do now, but they have given great service and have stopped well. Pads are still over 50% 60k+ later.

Thing is, recently when stopping, the steering wheel starts moving in a range as I apply the brakes. Side to side I suppose, but not horizontal motion, rather it moves as if I was quickly steering right to left with about 1" of motion back and forth in the wheel. Seems worse when using the brakes a lot, and it seems that heavier pressure mitigates it somewhat.

Car drives, rolls, steers perfect, no odd tire wear.

Is it safe to assume that the brakes are to blame? They stop well.

I can get bendix ct-3 pads for $18 and bendix rotors for around $20 each for this car, so want to pull the trigger if it is likely the culprit. No other indication that it's the suspension. Could it be something else? Does it on both my snow and regular tires.

Thanks!

 

[daman]

Sounds like the rotors are warped.

 

[Chris142]

Warped or the pad deposited thing i have yet to see.

 

[Quest]

slight uneven rotor warpage will do that to your steering.

I had that happened every now and then with certain brake pads+ rotor combinations, certain bendix ceramic brake pads, ATE ceramics, etc. will do that to the rotors (new ones, china made) in just mere 10,000kms....and the warpage will only worsen over time.

I usually ended up redoing the whole front set with new rotors and Monroe ceramics...and brake them carefully during the 1st 10kms...(no hard braking...just touch-n-accelerate...no crazy heating up of the rotors)...as the ceramic brake pads bed in, they will be good until the next round of pad change.

Q.

 

[Quest]

Originally Posted By: daman
Sounds like the rotors are warped.


It's a bedding issue with the friction material. More prominent with ceramics than semi-metallics due to less aggressive "biting" from ceramics until completely bed-in.

Q.

 

[NMBurb02]

Pad deposits. Apparently the difference in symptoms between warped rotors and pad deposits is that warped rotors will cause brake pedal pulsation and pad deposits will cause steering wheel shake. That's not my expert opinion (I am nowhere near an expert on anything automotive), just what I have read online at seemingly reputable sources.

The same thing was happening with my GP. One of the inner front pads was worn more than the others and its rotor face was also worn down with a pronounced ridge on the edge of the rotor. During pad and rotor replacement, I found that everything was caked in brake dust (the pads on it were apparently very poor quality as they dusted like crazy and the new ones have not dusted an appreciable amount in ~300 miles) and the caliper slide pins were noticeably pitted, both of which probably combined to hold that inner pad against the rotor after the brake pedal was released, heating up the friction materials and resulting in deposits. After the pad and rotor replacement, all is cured. I had not purchased new slide pins with the pads and rotors, but ordered and recently received ones, so I will go back in to replace those (and the brake hardware on one side as it was lost during the install).

I recommend replacing the pads, rotors (or get them resurfaced), and all hardware, including caliper slide pins.

 

[fdcg27]

Warped rotors are certainly a possibility, but so are the ball joints.
I'd check them first.
Warped rotors are an annoyance while failing ball joints are a genuine hazard.
Let us know what you find.

 

[Fleetmon]

My 528i would do that after my wife would drive it for a few days and I decided it was uneven pad deposits.....I would take it out and do several hi-speed stops, never letting the wheels stop completely, i.e. getting the rotors and pads extremely hot. It would typically cure the shaking for several weeks but slowly come back.

New pads and a proper bed-in would resolve it completely but it would always return months later. I never tried new rotors since my method seemed to work and new pads were only around $45 so it seemed like a pretty inexpensive fix to me.

 

[JHZR2]

If this were ball joints I think it would happen at all times under all conditions and temperatures. Having done a couple stops today from cold rotors, I can definitely say that when the brakes are cold, that the wheel does not shake.

I'll get it up to do a test but my guess is that the suspension is tight it really steersman handles quite well. I would also think that I would have been popping and other conditions if I had a bad ball joint when I'm handling the car around curves.

 

[Fleetmon]

As an fyi, mine didn't shake until warm to hot. I also noticed, occasionally, the imprint of a pad on the rotors but after my hard braking bed-in, the imprint was gone.