Steering wobble under braking

[Chrisgixer1]

Hi

slight creak front right while winding the steering from lock to lock, but… 

 

the main issue is a wobble…. Or tank slapper in motorcycling terms, from the steering wheel during certain braking conditions. Not hard braking that’s fine . But if you jab the brakes, or Brake gently it’s like the start of the first brake application sets up a wobble in play in the wishbones bushes or control arms or some component that has play in it allowing the road wheel position to flap and this is then felt at the steering wheel as a subtle left right left repeat  wobble that gently fades out or you stop braking
 

But I can’t find any play in any bushes. Rear control arms have been replaced by genuine Lexus but no change at all. Top mount looks on to me. I’ve pried every joint and all seems solid. No play in any ball joints. 
 

the only thing seems odd is play in the shocks shaft visible under the gator when prying the spring away from the top wishbone….it’s as the shaft enters the shock body but the car was jacked up wheels hanging so there will be very little shaft within the body, and anyway that doesn’t affect the wheel position or the steering, wiggle that all you like the steering does not seem to move when reaching through the driver’s window, there no oil weep the shock shaft is clean. Both sides are the same 

i could replace the shocks that’s fine bur I’m not convinced that’s the cause of the wobble at the steering wheel under gentle braking…? 
 

oh to add, wheels are not buckled brake disks run true to dial gauge tyres are round no bulges or anything un true, bearings are fine

[Redefined]

Have you had some brake work done recently... Or done a few unusually long drives!? If so, you might be experiencing a brake pad siezed. If youregood at the brakes-work then see if you can confirm that nothing is seized at the calipers (ie the pads or if they're 2 part calipers then maybe the sliders).

A simple check to perform if one of the pads is dragging on the disc is, after a long/decent drive - being careful, don't burn your fingers - check that all discs are cool enough to the touch. Maybe if you're not confident that you might burn your fingers then a tiny spray of water and check for sizzle.

If sizzle is seen one on disc but not the other then potentially that side is dragging the disc with the pads. Hope that helps,and as always, there could be lots of other explanations. But usually in my understanding if it's a bushing/bearing/alignment problem then the shake would come upon acceleration and not braking.

A pulsation (if it's brakes at fault) at the pedal upon braking suggests the rears... The pulse at the steering suggests the fronts. Hope you get it sorted as I kmow from exp, it's rather annoying and frustrating. Lastly, if any mechanic tells you that skimming the discs or swapping em is the cure, give em a slap (as they're not getting to the root of thr problem and it'll only come back in 900 miles of spirited driving).

[Chrisgixer1]

Thanks for your reply but the brakes have been done with new pads and discs after this issue started and made no odds as the issue remained 

the wear on the pads was equal both sides on each set. There is no unusual sensation from the brakes in feel or performance 

 

to me that fact that hard braking is fine suggests play and that play is taken up by braking forces as the weight of the car is thrown forward. 

 

Im really surprised not to find bush play tbh 

[Redefined]

Sorry if you've already checked but, front rear arm bushings?

[Chrisgixer1]

Replaced new if I understand the description correctly 

the ones that point at the gear box? Big round bush on the body end? New Lexus items no change sadly 

[Redefined]

Look forward to hearing how you get on. Hope it gets sorted soon and you'll update here. It's a right pest when stuff like this happens and it's a 'journey' to get to the bottom of it all!