DDow

Tapping Noise From The Rear End

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My 2004 RX300 64,000 miles, drives and performs as it should, and was an absolute delight driving down to Monaco and back last week, towing a heavy trailer for 1700 miles.

The only irritation is that there is a kind of tapping from the rear nearside (I think) when the car is driving down our unmade road and occasionally on the highway as well. (maybe when it is rocking)

Driving over normal lumps and bumps and pot holes in the road it is fine. The noise is not a heavy clonk as if the shocker/bushes have gone, and I have not noticed any handling problems from the rear. I was thinking maybe the anti roll bar setup, but that is just a shot in the dark. It really sounds more like something loose, swinging about, but I am at a loss what to look for, that is accessable.

Any suggestion would be gratefully received.

Suspension diagram attached in case it helps

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Could it just be loose gravel chips picked up from the nearside of the road (where they are likely to be looser) rattling in the wheel arch? If it was a fixed part of the car eg suspension etc) you would not expect it to be so specific to the road surface.

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Thanks for that. I may have overstated the surface type a little. It does tap a bit on made up roads but does not seem to coincide with suspension activating bumps. Not a stone rattle in the wheel arch sort of noise. I might almost say it seems to happen at slower speeds,

All suggestions appreciated,

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Have a look at the spare wheel enclosure underneath & the tool kit & boot compartments to see if everything is tight or if there is anything bouncing around ... or it could be the exhaust .... I had a similar thing on a shogun, if the exhaust angle isn't quite right or rubber mounts are missing/wrong ones fitted (short instead of long or vice versa) it can swing & tap underneath ..

If you have checked all the bushes/mounting arms etc the only other things I can think of would be a snapped coil spring or something has come loose inside a rear brake drum maybe a snapped brake shoe spring or retaining clip ?

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Thanks Dennis. I will take everything out of the tool kit/boot compartements first and give it a go

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I diagnosed a similar problem on my LS400 by sticking a GoPro in the wheel arch and filming the suspension over various terrains.

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Thanks all for the help guys. GoPro is a great idea as well. My lad wants one of those, he may have to wait a bit longer!

So, I spent an hour this morning looking in the "luggage" area.

Took my stuff out of the boot. Took all the tools and jack etc out of the storage area.

I loosened the spare wheel tensioner and re-tightened it.

The tooltray/box did not have the two plastic trim push fasteners, so had room to move. I replaced these to prevent any movement.

Some of the tools were a loose fit in their moulded places so I packed them slightly with some pieces of cloth. The jack when in place was slightly opened against its packing, again to prevent movement.

Made sure the rear centre fold down console was securely locked on its retaining clip.

Closed the lids and took it along my unmade up road, and all I can now hear is a very slight squeeking from the rear seats, leather on leather. I would expect that.

As I changed several things at the same time, can not tell what was the cause, but suspect the tools or the tool box moulding. I am just happy that the irritation has stopped, for the moment at least.

Allways felt it was not a suspension noise, but still pleased it did not result in having to replace the rears.

Thanks again for the suggestions.

Just to say, 1800 miles across France towng a vintage car on a trailer was a joy. The car was so comfortable as has been reported on other postings, gave on average 20-21 mpg.

Using the cruise control had the car changing gear a lot on inclines so I suspect turning it off resulted in better mpg and a more relaxing drive, at the cost of only a slight increase in journey time.

Great car,

Regards

David D

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Will try that Dennis. At least Grandma won't fall over on corners then. :winky:

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inside a rear brake drum maybe a snapped brake shoe spring or retaining clip ?

Brake drums?! On a Lexus?! Heaven forbid.... :-)

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inside a rear brake drum maybe a snapped brake shoe spring or retaining clip ?

Brake drums?! On a Lexus?! Heaven forbid.... :-)

Yes the Rx 400 has got drum brakes ... lol ... :-)

Wiki...

"In cars with rear disc brakes, the emergency brake either actuates the disc calipers (again, with much less force) or a small drum brake housed within the hub assembly (the inner circumference of the disc is often used instead of a separate drum)"

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http://st.club-lexus(blocked word)/attach/u/efec506b.pdf

Spotted this if it's more of a rattle than a knock....

I've got the same low rumbling knock on the passenger rear - sounds suspiciously like a strut mount on its way out - but everything checks out (without pulling it all to bits).

Only had the GS450h for a month so getting used to the noises, rattles, squeaks and knocks that shouldn't be there.

 

Most annoying is the handling (might be suspension related) - sports mode - hard out of a bend and the back end will 'tramp'...

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More likely ARB bushes - if you have air suspension they don't have rear strut top mounts per sé...

Sent from my Iphone using Tapatalk

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