Squeal when slowing

Lmafudd · May 23, 2023

Has anyone experienced a sound similar to a brake squeal but with no pressure on the pedal? I suspect it's regenerative braking that causes it but it's infrequent and I can't pin it down exactly. It's very loud and usually occurs when the car has been on a reasonable run.

ColinBarber · May 23, 2023

Squeal from the brake area when not applying pressure is normally an indication that the pads are worn and the wear indicator is rubbing against the disc (as it is designed to do). However given the age of your vehicle I highly doubt that.

Regen braking occurs via the electric motor in the transaxle and therefore should be easily differentiated from the brakes and I'm not really sure how the motor could make that kind of noise without also doing it when operating to power the vehicle.

If the noise is coming from the brakes then I suspect your brake calliper/sliding pins are somewhat seized and therefore the pads aren't releasing away from the discs correctly.

I would recommend I visit to your dealer but being an intermittent issue they may struggle to recreate the issue and waste your time. Have you tried some hard braking from 60-10 a few time in a row to clean up the pads/discs and help free the pins?

Lmafudd · May 23, 2023

Thanks for answering Colin. Only had the car for a short while and I am an extremely light braker but I'll give the vigorous braking a go. I haven't had any brake shoes/pads replaced in the last 20 odd years (5 or 6 vehicles) so I suppose that indicates how gentle my braking is. My last Lexus still had over 50% pads at 43000 miles!

Bill Dawes · May 25, 2023

I would suggest do what Colin said, a few hard applications of the brakes, at a decent speed, they probably have a glaze on them caused by gentle braking.

Bill D.

NemesisUK · May 25, 2023

Brake squeak/groan is common with hybrids and regen braking. As the mechanical brakes (pads and discs) are only applied at <5mph or in emergency situations the pads do tend to groan on application. Nothing much to be done but learn how to feather brake pressure to release pressure just before the car stops. I just live with it..

Lmafudd · May 26, 2023

19 hours ago, NemesisUK said:

Brake squeak/groan is common with hybrids and regen braking. As the mechanical brakes (pads and discs) are only applied at <5mph or in emergency situations the pads do tend to groan on application. Nothing much to be done but learn how to feather brake pressure to release pressure just before the car stops. I just live with it..

Interesting but I've never experienced this on the other 4 hybrids I've owned and I the squeal stops when the brakes are pressed hard (probably because the car stops almost instantly). It's going to the dealer on June 7th so we will see. Thanks for answering.

Lmafudd · September 3, 2023

Update on the 'squeak/squeal'. Dealer could find no issues and generally I haven't heard the noise - much' until yesterday. I drove through our village and heads were turning as the squeal was loud and persistent. Today none at all! When it occurred yesterday I did not have to touch the brake pedal and the noise was evident although never under acceleration. I am thinking it's the regenerative system that's at fault. It's booked in with our local Lexus garage on Friday when I will ask them to investigate, again.

stepppy · September 3, 2023

Have you tried putting the car in neutral as that disables the regen brakes? You can then give the brakes a good workout without any regeneration.

I do this on my Prius from time to time. It’s amazing how different it feels with no regen brakes.

Lmafudd · September 3, 2023

54 minutes ago, stepppy said:

Have you tried putting the car in neutral as that disables the regen brakes? You can then give the brakes a good workout without any regeneration.

I do this on my Prius from time to time. It’s amazing how different it feels with no regen brakes.

That could help me prove my theory Steppy. I'll give it a go.

EddyBaby · September 30, 2023

Yes, have had exactly this. Occurs after a drive of at least 5 miles and then becomes noticeable when driving at about 10 mph (often when returning home). Applying the brakes makes no difference and neither does steering right then left.

I doubt I will get anywhere going to the Lexus dealer as it is hard to replicate. I will report it to them at the next service in a few months.

RONNIE W HODGEKINSON · September 30, 2023

On 5/23/2023 at 11:06 PM, Lmafudd said:

Thanks for answering Colin. Only had the car for a short while and I am an extremely light braker but I'll give the vigorous braking a go. I haven't had any brake shoes/pads replaced in the last 20 odd years (5 or 6 vehicles) so I suppose that indicates how gentle my braking is. My last Lexus still had over 50% pads at 43000 miles!

There lies the answer to your Problem Colin " You Are A Very Light Breaker " The brakes Not Being actuated With Any Force Resulted in The Pads Sticking on The discs Thereby causing the Squealing.. Its an Easy Fix...And not worthy of a visit to the Dealership In My Opinion...

chris6922 · February 27

So I have had problems with heavy braking with a loud squeak noise, I’ve just had the front discs and pads changed and it’s still making the noise plus my UX is a2023 plate. It’s been to the dealer 3 times now and going foward is there a safety issue because Lexus can’t find anything else and have only changed pads and discs.

any suggestions what it could be ?

gdamorini · February 28

On 5/24/2023 at 12:06 AM, Lmafudd said:

Thanks for answering Colin. Only had the car for a short while and I am an extremely light braker but I'll give the vigorous braking a go. I haven't had any brake shoes/pads replaced in the last 20 odd years (5 or 6 vehicles) so I suppose that indicates how gentle my braking is. My last Lexus still had over 50% pads at 43000 miles!

I suggest you drive the car going downhill backwards (on a no traffic road) with the gear in neutral and braking, this way the brake pads will realign and get rid of any glaze.

Don C · February 28

13 hours ago, chris6922 said:

So I have had problems with heavy braking with a loud squeak noise, I’ve just had the front discs and pads changed and it’s still making the noise plus my UX is a2023 plate. It’s been to the dealer 3 times now and going foward is there a safety issue because Lexus can’t find anything else and have only changed pads and discs.

any suggestions what it could be ?

Why is there a safety issue going forward?

8 minutes ago, gdamorini said:

I suggest you drive the car going downhill backwards (on a no traffic road) with the gear in neutral and braking, this way the brake pads will realign and get rid of any glaze.

Explain how this happens.

On 9/30/2023 at 10:05 AM, RONNIE W HODGEKINSON said:

There lies the answer to your Problem Colin " You Are A Very Light Breaker " The brakes Not Being actuated With Any Force Resulted in The Pads Sticking on The discs Thereby causing the Squealing.. Its an Easy Fix...And not worthy of a visit to the Dealership In My Opinion...

Explain this please. Where and how do the pads stick on the disc?

gdamorini · February 28

25 minutes ago, Don C said:

Explain how this happens.

It's a mechanical way to realign the brake pads and clean them. It works on any car. On hybrid cars you need the gear in neutral so when braking you are only using the hydraulic system, bypassing the regenerative braking.

KentColin · February 28

I too sometimes get a squeal when applying the brakes but mine emanates from the passenger seat when my wife thinks I'm braking too late!

Lmafudd · February 28

My problem hasn't recurred since the Lexus Leicester mechanic took the brakes apart to clean a 'channel' that he says holds the brake/road dust. I don't know where this Channel is but it seemed to do the trick.

Lmafudd · February 28

I'm on 199 posts - this one isn't for any good reason other than to move my count to 200! 199 seems unlucky to me!

Boomer54 · February 28

58 minutes ago, Lmafudd said:

I'm on 199 posts - this one isn't for any good reason other than to move my count to 200! 199 seems unlucky to me!

You were right, brown envelope from the tax man tomorrow. Postal time lag effect.🤨

Maria12 · October 9

Hi, i experienced that noise today as i was driving a Lexus lbx , during a test drive. The dealer told me that this is a common noise for hybrid cars and it is made on purpose in order to warn the bypassers 😳! What an explanation!

Lmafudd · October 10

11 hours ago, Maria12 said:

Hi, i experienced that noise today as i was driving a Lexus lbx , during a test drive. The dealer told me that this is a common noise for hybrid cars and it is made on purpose in order to warn the bypassers 😳! What an explanation!

That noise is always there. We call it the 'UFO' noise.
My 'Squeal' is only when slowing - without braking. It only occurs occasionally, usually when just pulling into a car park, or similar, where there are lots of people moving around. They all look to see the 'Old Banger' making the noise of course.
When I wash the car I now blow out the front brake dust using a garden blower. There is always a good cloud of the stuff. Not sure it helps but as the issue is so infrequent I suppose that it is doing!