Brake warping

[Vlady]

Shahpor, I never disconnected the Battery doing front or rear brakes, when working on the rear ones I jut made sure the hand brake is released and that I have something under my front wheels to prevent the car rolling over. I am not saying this is right the way I did but it worked, so the garage you phoned just tried to justify higher price they charge.

As @Britprius says any machine shop will do it for £50! 

When I couldn't fix this judder issue I was so upset with the brakes, especially after coming BMW 5 series, that I was looking for another car and not a hybrid. After the brakes were fixed it was a different story, I am still not fully impressed with the brakes but not due to judder but due to it being a hybrid and the way brakes designed to work!

So, do not let your brake saga go for too long, get it done before you get disappointed in the car!  

Good luck Shahpor.

[ColinBarber]

On 7/29/2020 at 12:18 AM, Barry14UK said:

Certainly holding the brakes on whilst stationary if car has just previously had the brakes strongly applied can cause pad material to transfer to the discs.

Indeed.

I'd recommend trying to get an even transfer. Do 6 lots of hard braking from 50 mph to 10 mph one quickly after the other so the brakes don't cool between each run. The only difficulty is finding a quite bit of road to do it on.

[Shahpor]

4 hours ago, Vlady said:

Shahpor, I never disconnected the battery doing front or rear brakes, when working on the rear ones I jut made sure the hand brake is released and that I have something under my front wheels to prevent the car rolling over. I am not saying this is right the way I did but it worked, so the garage you phoned just tried to justify higher price they charge.

As @Britprius says any machine shop will do it for £50! 

When I couldn't fix this judder issue I was so upset with the brakes, especially after coming BMW 5 series, that I was looking for another car and not a hybrid. After the brakes were fixed it was a different story, I am still not fully impressed with the brakes but not due to judder but due to it being a hybrid and the way brakes designed to work!

So, do not let your brake saga go for too long, get it done before you get disappointed in the car!  

Good luck Shahpor.

Thanks Vlad, I very much appreciate it.

I will admit feeling a bit disappointed at first and questioning whether to move on car wise, but in the end, for the moment I haven't given up hope and will look at getting something done about it.

If I could afford the time off, I would consider removing the brakes myself and taking just the discs to get skimmed, but I have just started a new job and the pressure is on, so that is not an option for now.  It does sound like it is going to be an ongoing issue though...

23 minutes ago, ColinBarber said:

Indeed.

I'd recommend trying to get an even transfer. Do 6 lots of hard braking from 50 mph to 10 mph one quickly after the other so the brakes don't cool between each run. The only difficulty is finding a quite bit of road to do it on.

Sorry, perhaps I am being dense, but do you mean try this now to potentially get rid of the warping?

Thanks.

[Shahpor]

Incidentally, I have now received the video from the investigation that shows the run out of the disc at 0.2-0.3mm against a specification maximum of 0.05mm.

[Vlady]

14 hours ago, Shahpor said:

Incidentally, I have now received the video from the investigation that shows the run out of the disc at 0.2-0.3mm against a specification maximum of 0.05mm.

Does it men that they are worn?

[Shahpor]

No, it is the different in height between the low and high spots on the disc's surface.

The technical term is actually Disc Variation Thickness (DVT) so the number specified relates to the difference in disc thickness, which in my case is 0.2-0.3mm.

[johnatg]

Run out is the amount of 'wobble' as the disc rotates. It can be caused by DVT but it could also be that the disc is not sitting true on the hub. If the latter, that can cause the former.

[Shahpor]

Quite right John, it should be noted, like you say, that Run Out can involve a few factors, one of which might be DVT.

In fact, I was told that the Lexus technician did take off my disc and have a look at the hub to make sure it was clean, which apparently it was.

[aviator888]

On 7/30/2020 at 6:05 PM, Shahpor said:

 

Anyway, I tried a local skimming place and they won't do it because it is a hybrid.  He mentioned something about needing to plug it in to a computer to wind the pistons back into the calipers?  Also, they were afraid the pistons would jump out because of the electric accumulator.

 

Not sure if "Premier" models have different brake setup, but replacing the brakes on 2012 "Luxury" easy DIY takes about 2 hours complete with caliper clean and greasing the rear caliper sliding pins. Set of decent quality rotors and pads £250- £300 all in. Pushing back the pistons by hand is easy as pie. 

Hybrid GS is a heavy car and it takes toll on brake system. I wouldn't expect more than 2 years out of front rotors anyway as the rust will do it's job in this climate.  

 

 

[Shahpor]

Sadly, my car does have a different brake setup than the Luxury.

There was a thread on here a while ago about the cost.  Basically, all the GS models except the F Sport and Premier have standard 340mm front discs that aren't that expensive, however, the F Sport and Premier have 356mm 'floating' discs that are considerably more expensive.

I agree that removal and refitting of the brakes is a relatively easy DIY job.

[OldTrout]

17 hours ago, aviator888 said:

Hybrid GS is a heavy car and it takes toll on brake system. I wouldn't expect more than 2 years out of front rotors anyway as the rust will do it's job in this climate.  

Yes it is a heavy car but it is also a hybrid and hybrids that use charging the traction Battery to slow down are not as heavy on brakes.

John

[RgrWynne]

On 7/30/2020 at 1:30 PM, royoftherovers said:

Lexus Indie Garages (1).docx Time to consider an Indie Shahpor ? I`ve attached the current list.

Hi John, you do realise the irony in recommending an indie from your list, is that one of the garages is Jemca.
Jemca own Lexus Reading and are in turn wholly owned by no other than Toyota.

I was aware of the issue of warping brakes and the suggested causes as it happened to me with a Lexus 20 years ago. As a result ever since, when I have had to brake heavily I always release when safe, and reapply where necessary to allow the heat to escape. I have not had any further issues, but I find it as puzzling as everyone else, but not had a recurrence and to be fair it is rare I guess that we have to brake severely very often.

[Vlady]

@Shahpor how is it going, what have you decided?

[Shahpor]

Hi Vlad,

I haven't actually done anything about it yet.

I did find a place that will skim the disc's, but since it needs new pads at the same time, with labour they quoted £205.  This is still quite a saving over the £345 that Lexus want for new discs and pads but I am unsure what to do.

In the meantime I am just living with it, and with an MOT coming up in less than a month and 2 new tyres needed, I think I will probably wait and see what happens with those before deciding what to do.

I will keep you up to date either way.

Thanks.

[Shahpor]

Well, here's a strange one.

I haven't done anything differently, but there has been a significant improvement with a very much reduced amount of juddering under braking?

It is still there sometimes, but no where near as bad as it was, but I haven't done any hard stops or anything, so I am at a loss to explain it.

Now, if someone could solve the ridiculous amounts of squealing, that would be great  

[johnatg]

Maybe try lubricating the interface between pistons and backs of the pads with copper grease. Might help both problems

[Vlady]

8 hours ago, johnatg said:

Maybe try lubricating the interface between pistons and backs of the pads with copper grease. Might help both problems

I agree, that means you need to take the brakes apart, easy enough though. Clean them with metal brush, you can even buy a brake cleaner, some of it is very good stuff, and then apply lubricant on sliding parts, this should help with squealing. 

[Shahpor]

Thanks John and Vlad.

The dealer did say that have attempted this twice and afterwards that they all do it, so there is not much more that could be done according to them.

The annoyance is that it is squealing badly at anything up to 60mph when the brakes aren't being applied!  So, I will be just cruising down the motorway with the loud squeal in the background.

I have had noisy brakes before, but never when they are not in use.

[Barry14UK]

sticking caliper? deformed back plate?

[Shahpor]

Potentially Barry, but since the car is under Extended Warranty, it would be up to the dealer to determine and they claim otherwise, so I am reluctant to touch it.

Frustrating, but they had a look at the brakes as part of the investigation into the disc warpage problem and gave it a clean bill of health.

A sticking caliper would have also helped explain the disc problem, which is why I asked them about it specifically. 

You would hope, perhaps wrongly, that they would be able to see something as obvious as what you suggest....

 

[Vlady]

That squealing noise would drive me mad! 

As you say, I would expect Lexus technician to notice something out of normal when they were at it, or, all they did just visually checked all discs and pads without disassembling the callipers and lubricating every sliding part, including anti-squealing plate at the back of the pads.

Can you remove the wheel and check if the whole assembly looks clean and lubricated without removing the calliper? 

[Shahpor]

Well, when I had the brakes originally fitted they claim to have cleaned and copper greased the back of the pads.  I then complained about the noise (although it was only under braking at that point), so they took them out and re-applied the grease again.  The problem then appeared to disappear until recently.  That is why I suspected it was something to do with the disc problems because it seems to have happened at the same time.

They did take off the caliper as part of the checks and said they had checked to make sure it wasn't seized, so I am assuming they did have a good look.

As far as I am aware, copper grease doesn't need any annual re-applying or anything, so I am not sure what it could be.

I could manage a wheel removal, or at least I should be able to

Like I mentioned previously, I do have an MOT coming up shortly, so perhaps I will ask them to have a look again but I will have to make sure they don't charge me £186 to apply some copper grease that should have been fine the first time..

[Britprius]

On 8/21/2020 at 10:44 PM, Shahpor said:

Now, if someone could solve the ridiculous amounts of squealing, that would be great

I had this problem, and solved it by fitting self adhesive pads to the back of the brake pad back plates. This material can be bought on eBay, and is cut as required with scissors to shape. It is not expensive, and works well. From memory it is made by Ferrodo or one of the big name manufacturers.

John.  

[Shahpor]

Interesting, I will have to look and see what I can find.  This is the first time I am hearing about anything other than copper grease.

Would it be something like this?

https://www.ebay.co.uk/itm/SELF-ADHESIVE-BRAKE-PAD-ANTI-SQUEAL-SHIMS-FITS-MOST-MAKES-MODELS-BPF1299A-/231589276066

What is baffling is that it is happening whilst I am not using the brakes, which suggests that my discs and pads are rubbing all the time?

[Britprius]

15 minutes ago, Shahpor said:

Would it be something like this?

Yes that's the item. I knew it was by a well known maker, but could not remember who. It worked very well for me, and has been for a couple of years now.
For such a small outlay it is well worth trying.

John.