Steering wheel shake while braking but it's not brakes

[findalex]

Hi,

I have a head scratcher here.

On this 2006 RX330 FWD, 65k miles, sometimes when I brake, the steering wheel shakes violently.  But sometimes, it's really smooth.  I've noticed it shakes more often if I'm slowing and ther's a slight turn of the steering wheel.

At slower speeds, I can feel a type of pulsation from the whole car when I apply the brakes.  The pulsation feels like the deceleration rate increases and then decreases and increases again.  It almost feels like there some type of sway front and back as the car slows down.  I've replaced both front and rear with new struts and also the connecting rods recently.  The suspension is quiet otherwise.

I checked the tie rods for play and there isn't any.  The lower ball joint also doesn't seem to have much play, although I can't tell if some are leaking grease.  The lower control arm bushing is a little worn, but I've never heard of a bad bushing caushing steering wheel vibration.

Usually when the front rotor is warped, the shaking is there all the time and if you step on the brakes hard enough, the shaking reduces.  There is also no pulsation from the brake pedal.  So I don't think it's warped rotors front or back.

The tire wear is also pretty even on all 4 wheels.

Any ideas?

Thanks.

Alex

 

Edited September 15, 2023 by findalex
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[RX400h]

If this were my vehicle, I'd take it to my favorite alignment shop. They are experts at not only alignments, but also suspensions and brakes.

Sometimes what is not readily apparent to you, is "old hat" to the pros.

[dgorrie]

On 9/14/2023 at 11:11 PM, findalex said:

Hi,

I have a head scratcher here.

On this 2006 RX330 FWD, 65k miles, sometimes when I brake, the steering wheel shakes violently.  But sometimes, it's really smooth.  I've noticed it shakes more often if I'm slowing and ther's a slight turn of the steering wheel.

At slower speeds, I can feel a type of pulsation from the whole car when I apply the brakes.  The pulsation feels like the deceleration rate increases and then decreases and increases again.  It almost feels like there some type of sway front and back as the car slows down.  I've replaced both front and rear with new struts and also the connecting rods recently.  The suspension is quiet otherwise.

I checked the tie rods for play and there isn't any.  The lower ball joint also doesn't seem to have much play, although I can't tell if some are leaking grease.  The lower control arm bushing is a little worn, but I've never heard of a bad bushing caushing steering wheel vibration.

Usually when the front rotor is warped, the shaking is there all the time and if you step on the brakes hard enough, the shaking reduces.  There is also no pulsation from the brake pedal.  So I don't think it's warped rotors front or back.

The tire wear is also pretty even on all 4 wheels.

Any ideas?

Thanks.

Alex

 

 

[dgorrie]

My 2009 RX350 has/had similar symptoms.  My independent Lexus shop replaced one of the half-shafts up front (right side) and things got better.  I probably should replace the other side myself, but it’s not bad enough to warrant the effort or expense. Something to consider ….

[2grfebeliever]

It is worth mentioning that rusted/seized brake calipers can cause a shaking while braking which is very similar to warped rotors, and that the shaking can be there sometimes but not others because the brakes don't always seize up the same on each application.  I just went through this on my 2008 RX350.  I replaced the old rusted front calipers/pads along with the old rotors with new ones off of a 2010-2015 RX350, (the front ones will bolt right on) and the shaking while braking is now replaced with some very solid brakes.  Another symptom of seizing calipers is things like the car won't idle forward at a stoplight after releasing the brakes, and a generally very solid but sticky feeling pedal.  For braking symptoms, my car would shake the wheel more and more anytime I had to repeatedly use the brakes but be perfectly smooth on any isolated applications.  I did not have any brake pedal pulsation.

Edited August 4 by 2grfebeliever