LS430 knocking noise - goes away when braking

[vladls430]

Hi guys, recently bought a 2000 LS430 - had no issues on the first few drives, however recently a knocking noise has appeared that goes up with speed. When applying the brakes, the noise goes away almost completely, and it sounds like it's coming from the front passenger side.

 

I've had the wheels off, checked brake pads & discs, all bolts and everything seems tight as far as I can tell. The noise started out of nowhere, and it's been the same for the past week or so, it hasn't gotten any worse. The only thing I saw missing is the disc retaining screws, but don't think that would cause the issue. The car is on sitting on BC coilovers. Tyres are all good, all correct pressure and no visible damage to them. Have swapped the front wheels with different ones, and the issue still persists.

 

Any idea what this could be? All help is appreciated

[steve2006]

Hi Vlad and welcome to the LOC.

Being speed related have you checked for play in the wheel bearing, jack the wheel off the ground then rock the wheel with your hands placed at the 9 and 3 o’clock position and 6 and 12 o’clock position to see if you can detect any bearing play.

Other things to check although not speed related are the LBJ, UCA, ARB bushes and any other rubber suspension related bushes

[vladls430]

Hi Steve, 

Have checked both front wheel bearings - no play at all coming from them. I've noticed the front discs seem to be slightly warped, as my steering wheel wobbles whenever braking slightly harder, but not sure if this would create the knocking problem in the first place. The noise is quiet under 10-15mph, but going any faster than that makes it quite loud. 

Thanks for the help.