GS450h rear knocking

[NickySB]

Hi everyone

My GS450h (with around 113k) has developed a rear knock. It tends to happen when coming to a stop or pulling away, it’s not brake related as it does it if I allow the car to come to a (near) standstill without touching the brakes. It also does it sometimes if I go round a roundabout.  The noise also seems to move - i.e. it’s not always from the same area at the back. A preliminary look appears to sound like it’s from the prop or rear driveshafts so I thought I throw it out there so see if anyone has experienced this or knows of a common issue ?

thanks in advance

Nicky 

[LexIS200Sport]

My 2007 GS450h developed a knocking noise at the rear at roughly the same mileage. More audible at speeds <30mph and over uneven roads.

My first thought was worn swaybar links but the real culprit was the rear shock absorber. The noise has disappeared since replacing the rear shock. That shock was also leaking quite badly at the point when it was replaced.

 

[NickySB]

Thanks for the response. I had considered the shock as a small weep was mentioned on the last MOT, perhaps I’ve got more than 1 issue making the noise 

[NickySB]

just an update albeit inconclusive, I’ve not got to the bottom of this yet 😔 I would like to confirm what it is before spending £500+ on suspension, and of course since COVID hit the financial situation has altered. Had the rear of the car up in the air yesterday, but nothing conclusive. We do seem to have a little noise from the driveshaft but they don’t seem to be the typical culprit. 

[MNP]

My front near side shocker was replaced recently.  The knocking noise went and the ride has been transformed...it was a gradual deterioration. The old shocker was corroded and leaking.  I suspect that's what it will be...Mark.

[NickySB]

Yes I think you’re right, as was LexIS200sport, they’re just so expensive for the 450h 🥴 I am going to have to take the hit though - it will be wonderful to have a quiet ride again ☺️

[olliesgrandad]

41 minutes ago, NickySB said:

Yes I think you’re right, as was LexIS200sport, they’re just so expensive for the 450h 🥴 I am going to have to take the hit though - it will be wonderful to have a quiet ride again ☺️

Its not tyres is it. Dunlops wear in a strange way and give off a noise like a worn wheel bearing, but if it is a knocking rather than a rumble you are probably unfortunately correct. 

[Steven Lockey]

I believe someone linked somewhere on this forum that you could get the shocks for £250 each, far cheaper than the lexus price.

[NickySB]

Thanks , I’ve found them in a couple of places for around that price 

[NickySB]

20 hours ago, olliesgrandad said:

Its not tyres is it. Dunlops wear in a strange way and give off a noise like a worn wheel bearing, but if it is a knocking rather than a rumble you are probably unfortunately correct. 

I know what you’re saying about tyres - I’ve had to replace 3 in the last month ( got pot holed) but could still be a factor so I may change the 4th just to be sure - I was reading an interesting thread on an IS forum whereby someone had bizarre noises that transpired to be alloy corrosion and tyres so you never know 

[NickySB]

Thought  I would update the thread as we’ve just replaced the rear struts, as well as the 4 arms each side, hub bushes, both rear tyres , had the wheels refurbished and done some corrosion proofing. It’s not been out yet as I need to arrange to get the tracking done first. It’s fair to say the drivers strut was pretty knackered , leaked more fluid that I thought from inspection although in fairness I think all the arms and struts were original- I will advise how it drives ones it’s been aligned 

[LexIS200Sport]

Nice one. Pretty sure you'll immediately notice the step-up in ride quality  🙂

Interesting that you replaced the suspension arms though at ~113k miles. Was it because of perished bushes?

 

[NickySB]

No the bushes weren’t really perished but everything was so corroded I thought I would do my best to smarten it all up and prevent having to do work on the rear end again in the near future. All of the bolts underneath were/are seized so the camber and toe adjustment wouldn’t move ( I still need to loosen the control arm bolts somehow but I replaced all the bolts with OEM replacements.) 

[NickySB]

Pleased to report the knocking is gone 🙂

[The-Acre]

10 hours ago, NickySB said:

Pleased to report the knocking is gone 🙂

Good work!

[LexIS200Sport]

Happy days!