Rear brakes

[Richard1200]

Had my first service done a week ago and asked the dealer to look at the rear pads/brakes as they groan when holding on an incline unless the peddle is keep down hard. Anyway noise back after a few days so went back today. Nothing more they can do as they had taken the edges off the pads last week. It's being passed onto Lexus UK for their suggestions or approval of fitting new pads.

[rayaans]

Its normal - usually because they dont get used as much due to hybrid regen doing most of the work

[C Mclean]

Brakes were groaning like mad on my IS300h even after being cleaned and greased by Lexus. I didn't bother to do any more about it and have now found that my NX does the same. It seems to be a combination of the discs and pad material.

[rayaans]

My RX ones dont groan whatsoever whereas the IS ones groan but only at low speeds i.e. slow traffic etc.

They also dust like mad compared to the RX ones so a change in pads might do it - although looking at the service book - they dont go through pads very quickly!

[dutchie01]

i have thesame. it still irritates me every now and then. i dont think it adds to the lexus experience and the relentless pursuit of perfection.

this should not happen seems like the lexus standard is not as high as it has been? 

 

[rayaans]

2 hours ago, dutchie01 said:

i have thesame. it still irritates me every now and then. i dont think it adds to the lexus experience and the relentless pursuit of perfection.

this should not happen seems like the lexus standard is not as high as it has been? 

 

Its nothing to do with the standard of the car - its to do with the rear brake pads not getting much use and always having some kind of rust layer on them especially if parked outside

Mine is garaged and doesnt do it, unless its parked outside and its rained that is!

A few hard braking maneouvres sorts it out in no time, and I mean foot to the floor kind of braking from 30 to 0mph.

[capese21]

My previous IS300h was terrible for rear brake groan.  Lexus dealer dismssed it as normal. They didn't even attempt any kind of rectification.

My present GS also does it to a much lesser extent. 

I will try hard braking and see if it improves. 

My previous (non Lexus) car had little use less than 3k a year and lived outside and had lovely quiet brakes!!

Ed

[rayaans]

54 minutes ago, capese21 said:

My previous IS300h was terrible for rear brake groan.  Lexus dealer dismssed it as normal. They didn't even attempt any kind of rectification.

My present GS also does it to a much lesser extent. 

I will try hard braking and see if it improves. 

My previous (non Lexus) car had little use less than 3k a year and lived outside and had lovely quiet brakes!!

Ed

Doesnt do it on the IS250 or the IS200T so its definitely got to be the rear brakes not getting used much due to regen!

[capese21]

6 hours ago, rayaans said:

Doesnt do it on the IS250 or the IS200T so its definitely got to be the rear brakes not getting used much due to regen!

Or could the Hybrid drive be more demanding on the brakes from stationary?  

Ed

[rayaans]

5 minutes ago, capese21 said:

Or could the Hybrid drive be more demanding on the brakes from stationary?  

Ed

Unlikely. The rear brakes always seem to have a fair amount of superficial rust on the discs after rain even after being driven so I think its because the rust surface doesn't come off completely - its patchy. That'd explain why the hard braking would sort it too as it removes all the rust.

[dutchie01]

It does not add up. When i slow down and come to a standstill then that is the moment when the engine pulls the car further into the brakes and it always moans cracks tears or how you would like to call the sound that it makes. My car makes this sound in dry, hot wet and cold weather. It seems the pressure on the pads is not strong enough to fully grip the disc and fully stop the car. The sound is caused by the disc slipping through the clamping pads. Reading through the posts on this forum it seems a common thing on various hybrid models. So, is there a brake issue with the hybrids? it is not safety related but more a comfort related issue. Even if a possible cause could be forming of rust on the discs ( all discs from all cars have rust on them) or regen brake systems that are not as heavy used as non regenerative systems then that is not where the problem originates from. It starts in the beginning and that is the development/engineering of the car. If it goes wrong there it can only be changed in a midlyfe cycle update. It will be interesting to know if the new IS300H still has it or has it been adressed. I find this very disappointing for a Lexus the former worldchampion of NVH ( noise vibration harshness) and together with the drivetrain vibrations that my car suffered from and that are now for 85% gone after a dealer repair it gives an impression of a car that was not fully ready for production to Lexus Standards.

i recently drove a mercedes E250 diesel hybrid ( not the new model) and that worked without any problem...

           

[capese21]

1 hour ago, dutchie01 said:

i recently drove a mercedes E250 diesel hybrid ( not the new model) and that worked without any problem...

You wouldn't hear a slight noise from the brakes over that rattly old diesel tractor engine!! Why Mercedes keep on flogging that old 2.1 lump is a mystery to me. That is why I didnt buy one.

[rayaans]

1 hour ago, capese21 said:

You wouldn't hear a slight noise from the brakes over that rattly old diesel tractor engine!! Why Mercedes keep on flogging that old 2.1 lump is a mystery to me. That is why I didnt buy one.

Agreed you can't hear anything with that engine running. I know because I had a C220 CDI with the same engine!

I wonder if its just the hybrid system making the noise and not the brakes? It does sound like a gassing type of noise sometimes TBH. Its not really an issue for me as its so quiet and rarely happens anyway

[capese21]

It was quite noticeable (grunt) on my IS300 and definitely rear brakes, lightly pressing on the pedal and creeping along with no accelerator.  My present GS300h is only very slightly affected. I will try the hard stop and see if it clears it.

 

 

[ColinBarber]

3 hours ago, dutchie01 said:

So, is there a brake issue with the hybrids?

           

My old RX400h didn't do it, the RX450h loan cars don't and my wife's Prius doesn't. It seems to be inherent to the IS300h and GS300h. I've not had a look but they may use a different brake design compared to older models (hopefully to try and address the sliding pin seizure that has plagued Toyota models for years).

It seems to be an issue with very light mechanical braking on the rear which glazes the rear pads which then causes the noise. My dealer cleaned up my pads and it resolved the issue for a few weeks and loan IS300h vehicles (100 miles on the clock) didn't have the issue either. Performing some heavy braking also seems to help clean up the pad surfaces.

[Richard1200]

My rear discs now have about 10mm of rusty grooves near the hub center where the pads are not touching.

new discs and pads being fitted next week. 

[capese21]

A set of Wagner Thermoquiet ceramic pads,new mounting clips and the correct grease on the guide pins has totally eliminated brake grunt on my GS300H. The guide pin grease is very important and often a copper or red rubber grease gets used neither of which is suitable for the guide pins. (correct grease is Molykote G3407 or TRW PFG110)

I refused to accept Lexus dealer saying it was normal

Ed.

[Finzky]

Hi, I`m facing now the same issue big time! I bought the car a bit more than one month ago and brake groaning (low deep noise creak) is just unbearable, it`s so embarrassing for the brand new 35k car. I will call my Lexus dealer today with request to sort it out, no matter how I love this car I`m prepared to give it back. I will keep you updated how it goes with them,  this is one of the biggest frustrations in Lexus so far. 

[Mr Vlad]

I notice a groaning type noise on slow braking too. It sounds to me like it' s discs being cleaned by the pads. It doesn't bother me one iota. It also sounds like a regeneration progress noise. I only notice it really in between music tracks if I happen to be braking.

[rayaans]

On 14/12/2017 at 1:27 PM, Finzky said:

Hi, I`m facing now the same issue big time! I bought the car a bit more than one month ago and brake groaning (low deep noise creak) is just unbearable, it`s so embarrassing for the brand new 35k car. I will call my Lexus dealer today with request to sort it out, no matter how I love this car I`m prepared to give it back. I will keep you updated how it goes with them,  this is one of the biggest frustrations in Lexus so far. 

They don't get used much at the back so need some good emergency braking procedures.

Also its worse if the car is parked outside as they inherently rust up in bad weather.

Mine's garaged and gets used fairly well once a month atleast so it keeps them clean

[Finzky]

Just came back from appointment. Had a drive around with Lexus technician and then they took me for a spin in the same model to compare. Need to admit I was probably panicking to much, because everybody have the same problem with brakes, maybe it`s just my ears are to sensitive. I requested to find one non hybrid IS, because I want to compare it to hybrid one and we will see, maybe petrol turbo will work out better than hybrid.

However they do admit that during cold winter months when there is lot of salt on the roads it corrodes brake discs and pads and that makes brakes work louder than in other seasons, proof to that is my brake sound become more quiet.   

[Notamech]

Reviving this old thread. Did anyone manage to find a solution or is this normal? I just noticed mine today and a search lead me here. Its exactly like the OP describes in slow stop and go traffic everytime i brake after moving a short distance at low speeds, the car stops and theres a loud groan from the rear brakes. It sounds like when you don't apply enough pressure to the pedal on a non hybrid car and the pads engage just enough to touch the disc but not stop the car and you hear a groan. And it feels like the computer / brake actuator is compensating and adding more brake pressure or something. Does anyone know what this is? 

[Notamech]

So i think I figured this one out and its probably normal. If i use a stronger braking force and apply more pressure on the pedal then i do not hear the groan. Im just so used to gentle braking especially because of the regen braking i keep a light foot on the brake. I think it is actually what I thought it was i.e the computer compensating for lighter braking force. I could be wrong but if anyone has any other explanation let me know. 

[ColinBarber]

13 hours ago, Notamech said:

I think it is actually what I thought it was i.e the computer compensating for lighter braking force

No, it is just the pads lightly pressing against the discs causing the noise. Try a few hard stops from 60 to 10 mph to clean the pads/discs otherwise just replace the rear pads with something that has a different compound - EBC yellow or green stuff for example.