Knocking from rear suspension

Jayw13702 · December 3, 2018

are there any common items that cause knocking noises in the rear of the IS300h?

I have a knock coming from the NS rear, its not loud, but its there. Nothing appears to be loose and the noise only appears when its wet, so currently its driving me nuts as its constantly wet.

My first thought was rear anti roll bar drop links, they seem to be the common cause for knocking on most modern cars.

route66 · December 4, 2018

I'm not aware of any problem with IS300s in this area myself.

Just a suggestion - check under the boot panel. There are lots of cubbies there and great scope for something to make a noise like you describe. In my case, I store the lock nut for the wheels in there and this has been known to make a rattle.

On a completely unrelated note, can't wait to hear of your experiences of a gearbox oil change. I'm guessing you will be the first in the world to do it (or at least, to write about it) so we could be talking about something big here - video it and put it up on Youtube. It will go viral and you will make many £millions 😁

200h · December 4, 2018

i'm on my 2nd IS300h and have never had any form of knocking noises

Jayw13702 · December 4, 2018

Thanks for your comments.

i've managed to secure a half day on a ramp so I will be doing the transmission oil change soon and looking over the rear suspension as well to see if I can see anything clearer this time.

Given that its now close to 85K and spends its life trecking around as a taxi I'm expecting to have to replace suspension components before long. its an occupational hazard

Ievil · February 19, 2019

Thanks for your comments.

i've managed to secure a half day on a ramp so I will be doing the transmission oil change soon and looking over the rear suspension as well to see if I can see anything clearer this time.

Given that its now close to 85K and spends its life trecking around as a taxi I'm expecting to have to replace suspension components before long. its an occupational hazard

Have you spotted anything, got similar issue. 3 garages, 4 mechanics and no one found the problem. It's the rear passenger site wheel. My colleague who works for Jag had it on the ramp and suspect rear lower trailing arm bushing

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The-Acre · February 20, 2019

I had a slight knocking sound from the front of my GS300 but no mechanic ever found the source. I replaced the anti roll bar bushes and the drop links to no avail.

PaulWhitt20 · February 20, 2019

Are you sure you haven't left the Mother in Law in the boot?

darrude · March 2, 2019

On 2/19/2019 at 11:26 PM, Ievil said:

Have you spotted anything, got similar issue. 3 garages, 4 mechanics and no one found the problem. It's the rear passenger site wheel. My colleague who works for Jag had it on the ramp and suspect rear lower trailing arm bushing

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Hi I've got a slight knock, only noticeable on slow poor roads, mentioned at last service but they couldn't find it. I'll mention your comment. Thanks for sharing.

Ievil · March 2, 2019

Hi I've got a slight knock, only noticeable on slow poor roads, mentioned at last service but they couldn't find it. I'll mention your comment. Thanks for sharing.

Found The problem, here is the picture of faulty shock absorber, just as I was expecting it is leaking

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darrude · March 2, 2019

Mine sounds exactly like the knock I had from a shock on my last car, so that's what I suspected. Did you change it yourself?

Ievil · March 2, 2019

It took me nearly 3 hours with neighbour's help and couldn't undo bottom screw. Taking it to the garage nearest Monday if find time. But now its 100% confirmed it's the shock. The leak could not be seen until wheel was off, car is jacked as on the picture to have shock fully extended, it is wet on very top

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Ievil · March 8, 2019

All sorted, rear shocks replaced and no more knocking noise. Handling improved as well. Highly recommend to check shocks. Thanks

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The-Acre · March 8, 2019

28 minutes ago, Ievil said:

All sorted, rear shocks replaced and no more knocking noise. Handling improved as well. Highly recommend to check shocks. Thanks

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Well done, expensive?

Ievil · March 8, 2019

£262 per shock, labour £60

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The-Acre · March 8, 2019

13 minutes ago, Ievil said:

£262 per shock, labour £60

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Just imagine what a main dealer would have charged for the whole job!

Ievil · March 8, 2019

Suspect lexus price between £700-£800

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wharfhouse · March 8, 2019

Unfortunately the Lexus website doesn't have the IS 300h prices for common repairs yet, but on the last gen IS 250 the Essential Care price for a rear shock absorber fitted is: £295 per side

Ievil · March 8, 2019

Unfortunately the Lexus website doesn't have the IS 300h prices for common repairs yet, but on the last gen IS 250 the Essential Care price for a rear shock absorber fitted is: £295 per side

Front or rear?, rear ones are more expensive somehow

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wharfhouse · March 8, 2019

5 minutes ago, Ievil said:

Front or rear?, rear ones are more expensive somehow

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That was for the rear - fronts for the last gen IS 250 are listed at £325 per side - as I said it may well be different for the current gen IS 300h though