Thumping Noise Rear Suspension?? LS460 2007

[SH20]

Dear all, anyone experienced what I can only describe as a thump coming from the near side rear suspension when the car travels over any irregular patch of road surface. Only exception is motorway use because the tarmac tends to be super flat and smooth.  On any other A or B roads no matter how fast or slow I travel the rise or fall of the suspension  over bumps  coincides with a thumping sound either a single thump or a few rapid thumps depending on the road surface problem.  It can be heard as low as 3mph or any speed above that.  

Best way I can describe the noise would be when an exhaust section or box has become mis aligned and comes into contact with the body as the body rises and falls over uneven roads.  That's how it sounds but I suspect the air ride strut is bottoming out somehow and wonder if anyone can confirm what component is responsible.   My dealer who serviced the car and did the MOT today confirmed they heard it on road test and their subsequent examination of the suspension couldn't find anything which might account for the annoying non stop thumping. I needed to get back home which is 120 miles from the dealer I use so agreed to come back to investigate further.    I have Lexus warranty and will hope it will cover the fault eventually when someone can explain what's going on.   Any pointers would be gratefully received.

 

 

 

[dendonc]

2 minutes ago, SH20 said:

Best way I can describe the noise would be when an exhaust section or box

Maybe put some kind of recorder on (phone/camera in vid mode) & upload to youtube so folks can hear it

[The-Acre]

I think you would see it and feel it if a strut was as you say, bottoming out.  It may be a duff height sensor. Can you see a noticeable difference in height at standstill?  Does it go down at the rear when parked overnight?  It doesn't necessarily mean it's coming from the suspension.

[SH20]

Thanks guys for the feedback,  No height issues either side and certainly doesn't drop on the near side overnight.    It just feels like something moving up and down causing the thud.   The very best example of the thumping sound is when I go over a sleeping policeman i.e the hump that goes across the  full width of the road at about 3 mph.  When both rear wheels hit the raised tarmac the body rises and then falls in a second and this is when the sound is most noticeable.  Taking the speed bump at a slighter faster speed increases the severity of the thump.   So I'm convinced it's all in the vertical movement of something.   I'm wondering if the top plate bushing of the strut is worn.  It's a very dull surpressed sound like it's muffled.  Anyway when it's sorted I'll report back what was replaced to cure it.      

[SH20]

Confirmed by my dealer, the thumping sound was the near side rear air ride suspension strut.  £1000 repair but done under my extended warranty.   Held in place by one huge 19mm nut at the bottom of the strut and 3 nuts at the top plus electrical connections.  The  rear near side seat had to come out as the top mounting plate  is inside the car as opposed to the old style of shock absorber of long ago which was accessed in the boot.    But at 65000 miles I was surprised that it had failed at a modest mileage for a 10 year old car.  I guess the off side strut is potentially the next issue I might be dealing with.   

[The-Acre]

Be thankful it's under warranty!  A problem with many vehicles with air suspension sadly.  There's an S class Mercedes parked near my house that always goes right down overnight.  It all seems to be pot luck, some last 250k (and more) others 60.  Did yours get gradually worse or just suddenly happen?

[GrahamG]

The only good thing about air struts is that when one fails it is not necessary to change the one on the other side at the same time.

As Phil says the others might last 250k miles.

Apparently it pays to renew struts soonest otherwise violent motion can damage the ride height sensor and that's another £350.

[cruisermark]

It would probably be very wise to have a lexus inspection done if buying a LS460 or LS600H (and hybrid health check)

 

[Newbie1]

Doesn't seem to be mileage that affects these air struts but age. Soarer air suspension units started failing from about 10 years following the date of build, regardless of how few miles were put on them. I know of someone who replaced all four air bag units in a Soarer a few years back only for one of the new replacement bags to fail within 6 months.