Is300h Front end slight noise knock ,drop links ?

Colinb623 · January 28, 2023

Hi all

Been trying to diagnose a very slight knock from the front end of my 2016 f sport 300h . It happens ever so slightly over rough ground .

I have noted today how easy it is to move my front drop link left and right with my hand with hardly any force.

Should these drop links be alot more solid or stiff and would this be the cause of my noise if they are failing ?

cadman2k · January 28, 2023

If a drop link has movement it's normally the sign of a worn bush/rubber that's in it.....normally causes a clunk noise...what sort of mileage have you got on the car, wouldn't expect these to go till about 70k miles minimum, that said state of UK roads in certain places is shocking...speed bumps don't help either..you can sometimes simulate it by getting someone to push up and down on the car from the outside while your in it, I say this on cars that are light but not sure on a lexus as they are heavy/well built cars.....on the positive side they are not that expensive either so shouldn't bust the bank on replacements

Colinb623 · January 28, 2023

Thanks cadman. I ordered a set of front links there from my local autofactors. Not that expensive.

To me the lateral movement in the link is too much so that's why I'm suspicious of them .

I'm going to try what you suggested though 👍

agent_dess · January 28, 2023

I've been getting popping sound ever since my mot. It can be replicated by reversing and slamming brake then you get a pop/clunk and then when you do the same thing forward then it goes away until you ha e to reverse. I got rid of the noise after a week by slamming brake really hard In both directions.

Noise happened again last week it was in for a service at lexus. It's going on Monday for ball joint replacement cause it had a split so I also mentioned the noise they will look while doing the work.

Notamech · January 29, 2023

20 hours ago, agent_dess said:

I've been getting popping sound ever since my mot. It can be replicated by reversing and slamming brake then you get a pop/clunk and then when you do the same thing forward then it goes away until you ha e to reverse. I got rid of the noise after a week by slamming brake really hard In both directions.

Noise happened again last week it was in for a service at lexus. It's going on Monday for ball joint replacement cause it had a split so I also mentioned the noise they will look while doing the work.

That sound could most likely be the brake pads moving within the calipers. Happens once when you change direction i.e forward vs reverse. If you or the prev owner installed aftermarket brake pads or had brake pads installed from a non lexus garage they probably didn't install them with all the original shims / fitting kit. I have a similar problem on the front wheels. lexus quoted £275 to put shims just on the front. Will probably buy the shims online and get it installed elsewhere.

agent_dess · January 30, 2023

On 1/29/2023 at 9:03 AM, Notamech said:

That sound could most likely be the brake pads moving within the calipers. Happens once when you change direction i.e forward vs reverse. If you or the prev owner installed aftermarket brake pads or had brake pads installed from a non lexus garage they probably didn't install them with all the original shims / fitting kit. I have a similar problem on the front wheels. lexus quoted £275 to put shims just on the front. Will probably buy the shims online and get it installed elsewhere.

There genuine brake pads and all new shims all round. Brakes i did back in the summer, the noise started when it went for MOT in december.

agent_dess · May 24, 2023

Reviving this topic as im still experiencing the clunk noise when breaking, it feel like it's coming from the front. Never happens over speed bump.

The way to replicate the issue is to:

reverse, brake <clunk> then drive forward and brake <clunk>.

Really starting to p!$$ me off now. I plan to take brake pads apart for annual clean and lubrication.l in a few weeks.

Looking for any other suggestions? Is it possible the control arm is loose? As I said in my earlier post it all started the day of the MOT back in January when they must have had it on the rolling road.

IS300FSPORT · May 25, 2023

12 hours ago, agent_dess said:

Reviving this topic as im still experiencing the clunk noise when breaking, it feel like it's coming from the front. Never happens over speed bump.

The way to replicate the issue is to:

reverse, brake <clunk> then drive forward and brake <clunk>.

Really starting to p!$$ me off now. I plan to take brake pads apart for annual clean and lubrication.l in a few weeks.

Looking for any other suggestions? Is it possible the control arm is loose? As I said in my earlier post it all started the day of the MOT back in January when they must have had it on the rolling road.

I had a similar issue many years ago although this may sound bizarre/unbelievable the suspension just needed a reset.

Lift both wheels of the ground at the same time same axle.

- Front jackup on Subframe

- Rear on the differential

Let it sit with the wheels of the ground for couple of minutes to realign & drop it down slowly. I genuinely dont know how this worked but it did the trick for me the clunk went away, start with the basics.

Failing that the noise could be anything, from something in the boot perhaps a loose jack, Battery or any other items.

Or a caliper sticking, ball joints, control arm bushings,drop links etc

If its not obvious when driving forward dont worry about it.

agent_dess · May 25, 2023

Only problem is you could be driving along the road and suddenly you need to slam the brakes on and that is when there is load pop like packet of crisp opening.... its scares the passengers in the car lol

Now about what you have suggested car .. in Feb the car went to lexus for new front ball joint replacement, i did ask lexus to investigate the clunk sound, but they said they didnt have enough time ($$$ 🙃). so they would have had the car in the air, ive had wheel alignment done twice this year too! dont ask bloody potholes.

I think i will go round the whole car and check for anything loose, but my mind keeps going to front of car as sometime when it happens it feel like its coming from the front of the car.

I will start with brake pad inspection... maybe even visit indie mechanics for suggestions.

Brian R · May 25, 2023

I've read and heard about similar symptoms, and some of these have turned out to be engine mounts. To rectify this has been down to full on replacement or tightening of the mounts. You might also like to check the tightness of any braces you might have within the engine bay or at the rear of the car and as applicable.

Digifant · May 25, 2023

Control arm rear bushings. My nearest future repair.

Mr_Groundhog · June 9, 2023

I had a similar noise when I got my previous car (honda civic 9th gen, with 38k miles) ...it turned out to be one of the anti-roll bar links that was broken.

I guess most people are pretty careless about speedbumps, potholes and other imperfections whereas im pretty OCD about them (I somehow feel the suspension is a delicate thing) so the previous owner must have been one of those.....that plus the total state of UK roads of course, for which we pay plenty of road ta but see no improvement....

In the end I replaced both links for peace of mind and the noise was gone. Using the video above, I'm talking about this piece in the screengrab:

BTW @Digifant I did replace the front arm bushings with those of the GS-F (so they're still OEM pieces) and the change isn't major but you do feel the steering a bit more grounded and firm. A tad more sensitive (in a good way). I got them from Amayama I think.

Digifant · June 9, 2023

9 hours ago, Mr_Groundhog said:

I had a similar noise when I got my previous car (honda civic 9th gen, with 38k miles) ...it turned out to be one of the anti-roll bar links that was broken.

I guess most people are pretty careless about speedbumps, potholes and other imperfections whereas im pretty OCD about them (I somehow feel the suspension is a delicate thing) so the previous owner must have been one of those.....that plus the total state of UK roads of course, for which we pay plenty of road ta but see no improvement....

In the end I replaced both links for peace of mind and the noise was gone. Using the video above, I'm talking about this piece in the screengrab:

BTW @Digifant I did replace the front arm bushings with those of the GS-F (so they're still OEM pieces) and the change isn't major but you do feel the steering a bit more grounded and firm. A tad more sensitive (in a good way). I got them from Amayama I think.

That will be my next check after I finish with the bushings.

agent_dess · June 25, 2023

So i took the brakes apart on Thursday night to clean and relubricate hoping this would resolve my issue. while its much better than before its still not solved.

What i did discover was when i had the tyre off on the rear n/s (passenger) when i tried to wiggle the whole suspension/control arm section it was making a strange squeakish clunky type sound, i then checked the rear o/s (driver) and that was solid and no noise.

At this point its beyond my tool and skill level, ive got friday off so will be going along to local indie to get to the bottom of the issue.

since the brake clean i can replicate issue by:
reverse > brake [clunk clunk] > forward > brake [clunk] and then fine for a while. Also see to get the noise when on a downward slope and braking.

agent_dess · June 30, 2023

My final update on this.. turns out the caliper carrier bolts weren't anywhere near as tight as they should have been so when breaking there would have been enough slack to cause the clunk noise. All sorted by my indie garage.

matt8 · June 30, 2023

1 hour ago, agent_dess said:

My final update on this.. turns out the caliper carrier bolts weren't anywhere near as tight as they should have been so when breaking there would have been enough slack to cause the clunk noise. All sorted by my indie garage.

The best fixes are the easy ones like this!