BRAKES/ discs warped,calipers? IDEAS?

[AndrewLast]

Hi 

Since few mths ago i started having problems with my brakes on my 2015 Lexus IS 300h. Went to a mechanic and been told FRONT discs are warped as he measured/checked them so got new discs from Lexus changed them and new pads so all good for a mth or so then back to the same problem and to the mechanic. Again took discs off and went for skimming as i was told not to buy new ones again. One was warped so fix it and put then back on the car. After about 2 mths again the same problem so went and got again new discs and pads. Everything ok for a while but now same problem back again. No one knows the exact problem. ANYONE any ideas,please.Tired of buying and fixing the same things again and again for the last 6 mths and they are expensive too.

Thank you 

[NemesisUK]

Make sure the disc to hub mating surface is spotlessly clean when fitting new discs.

Before replacing anything try a few emergency stops from high speed, (where safe to do so!) but don't come to a complete stop each time. This will clean off any pad deposit from the disc faces. If the problem goes away it could be your driving style is causing the issue. Do you come to a stop from speed and hold the brakes on?

[AndrewLast]

6 hours ago, NemesisUK said:

Make sure the disc to hub mating surface is spotlessly clean when fitting new discs.

Before replacing anything try a few emergency stops from high speed, (where safe to do so!) but don't come to a complete stop each time. This will clean off any pad deposit from the disc faces. If the problem goes away it could be your driving style is causing the issue. Do you come to a stop from speed and hold the brakes on?

Everything was cleaned properly,been there seen it...sandpaper used,still brush and all. Did tried emergency stops too.

As i said changed discs 3 times and still not ok. Thinking about replacing calipers but been told they are ok. 

[NemesisUK]

34 minutes ago, AndrewLast said:

Did tried emergency stops too

And any difference?

What were/are the symptoms you experienced?

Did your mechanic use a dial gauge to measure the disc run-out?

If you've tried everything suggested and still have issues I'd suggest finding a different garage/mechanic.

[Mr Vlad]

Hi Andrew. This must be a very annoying issue and one which I find unbelievable on that car. I would advise taking your car to Lexus and get their opinion and get remedied. There must be an underlying issue which Lexus should sort.

I've never heard of such an issue or experienced it and I drive like a looney.

[GS300h2014]

I believe your car has sliding pin calipers. A relatively cheap next step would be to get a different mechanic to check that the sliding pins do slide and that the pads are not jamming in the pad carriers as mechanics don't always derust the carriers before fitting new pads.

[Cotswold Pete]

I always scream when I hear 'a mechanic says the brakes are warped'.  Discs only warp if run red hot glowing and then you hit them with a ruddy great hammer, and as they cool down they are now warped.  Either that or the discs are made of such cr*p metal they warp because they are just good at bending themselves, but you still would need to lump the disk with some force that no brake pad is ever going to exert.

I had problems with my LS until I went back to OEM disks and OEM Pads new shims and a darned good clean up of all that is to do with braking, and also making sure after any period of braking to take foot of the brake pedal and apply handbrake or park.  Any inferior junk in any brake pad is more likely to stick itself to the disk when both are heated and stationary (so no air moving over the interface).

The pads may be sticking more than usual due to other problems with the braking system, which comes from the other parts bringing pad and disk together are possibly sticky/sticking or slightly out of true.

As you have (from the sounds of it) already had new OEM discs and pads, gotta be something else, and making sure foot off brake pedal is the order of day as soon as you come to a stop (eve for a few seconds).

I feel for you having been on the same journey over 2 years with various mechanics who wanted to un-warp my discs.

[hockeyedwards]

Had to giggle a bit as my dad has had many a discussion with 'mechanics' about how they 'know' discs are 'warped' and he made similar sentiments.

I suspect though as mentioned above, if you have replaced both discs and pads, but the problem persists, it is not the pads or discs but rather something further up the chain.

What are the symptoms that lead you to seek a mechanics opinion on your brakes? Might give some further clue as to what is the actual culprit.

 

[AndrewLast]

4 hours ago, NemesisUK said:

And any difference?

What were/are the symptoms you experienced?

Did your mechanic use a dial gauge to measure the disc run-out?

If you've tried everything suggested and still have issues I'd suggest finding a different garage/mechanic.

No difference at all.

Been to 3 mechanics,all used to gauge for measurements. Even called lexus told them that i got the discs(parts) from them and explained what happend,symptoms and all and within a few weeks since i bought the discs from them they got warped. Been told that i have to leave the car with them to investigate the matter sending the complaint to some place and that might take up to a week and nothing else could be done. I need the car cant leave it there for a week or so and they said u better change the calipers too but the price they gave me for 2 calipers is crazy. About 700-800 euros parts only.

[hockeyedwards]

And how exactly 'warped' were the discs with these gauges?

Also apologies for the repeat, but what are the symptoms you were experiencing...

[AndrewLast]

1 hour ago, hockeyedwards said:

And how exactly 'warped' were the discs with these gauges?

Also apologies for the repeat, but what are the symptoms you were experiencing...

They were warped 1st and 2nd time from the measurements. 3rd time just i change them without any measurements.

symptoms: when i push the pedal bit by bit seems to be ok but when i push it harder and longer feels a bit shaking kind of or like pedal goes up and down a bit. Thats the feeling 

[AndrewLast]

5 hours ago, Mr Vlad said:

Hi Andrew. This must be a very annoying issue and one which I find unbelievable on that car. I would advise taking your car to Lexus and get their opinion and get remedied. There must be an underlying issue which Lexus should sort.

I've never heard of such an issue or experienced it and I drive like a looney.

Was thinking about that,been talking to them last week when they did my service (oil,filters) and been told they should investigate the matter but for the begining i should thinking about startimg with changing the calipers which will cost me about 7-800 euros for 2 parts only. Thats mad

[AndrewLast]

3 hours ago, GS300h2014 said:

I believe your car has sliding pin calipers. A relatively cheap next step would be to get a different mechanic to check that the sliding pins do slide and that the pads are not jamming in the pad carriers as mechanics don't always derust the carriers before fitting new pads.

Hi. Should i change this pin calipers or fix them? Car is only 5 yrs old 75000km(47k mls) on the clock. 
Never ever in my life had such problems with any car 

Edited December 14, 2020 by AndrewLast
Didnt finished all sentences. Hit send by mistake

[hockeyedwards]

Food for thought...

Could have just been uneven pad material building up on the braking surface on the disc.

Most discs are unlikely to actually be warped, new discs are even more unlikely as they haven't been through enough heat cycles.

Were the calipers cleaned sufficiently after replacing the first set of pads or just whammed in without a decent clean out? I did my F's front pads and the calipers were full of old brake dust, clean the shims too and reapplied copper grease before putting in the new ones.

Have you gone through any sort of bedding in process for the new pads? Unforunately I am not super in the know of the pad quality for the IS300h's and whether they require it or not?

Also I am very sceptical of the suggestion 'change the calipers' - why? What is the diagnosis/ investigation that proves this is the problem?

If you just start blanket replacing parts blindly you might 1) gain no insight into what the actual underlying problem was/ is and 2) develop unnecessarily deep pockets for something that could have been a simpler/ cheaper fix. Some times a little patience goes a long way and saves you some of the queens pounds!

 

[Cotswold Pete]

Totally agree with Kieran about a darned good clear out and making sure shims and copper grease sorted.

If calipers are not 100% moving as needed, then chances are the pads are sitting on the disk when they should not be, they then start bonding small amounts of material to the disc, and over time the disk surface is out of true.  I would say lumpy surface not a warped surface.  Once this process begins then the only way is to clean the disc as well as the pads, and work out what is causing pad to disc contact when there should be none.

I assume if runout not correct then that causes problems from the word go.

Also seen some people say a dirty interface between wheel and hub can cause odd problems, but usually when there is really significant build up of filth on the hub.

Being in Dublin its a shame you could not take the care to Japex in Hemel Hampstead, they might have some ideas.  Maybe they might know of a company your side of the water that could help.

 

[Barry14UK]

Yes it's also essential that the wheel surfaces that mate with the discs are clean and true and that the wheel nuts are gradually tightened in an opposing pattern and finally to the correct torque.  I would expect a mechanic would do this and because it's difficult to check run out on the discs with the wheel in place.  Sometimes, you can have a sticking caliper piston which means pads drag on the affected wheel. This could cause brake pad material to be deposited on the disc in the same way as can happen if brakes are held on to a disc when hot.  However, one assumes the OP is an experienced motorist and would be aware of this.   It's possible that some crud is stopping both caliper pistons fully freeing off but unlikely.  It is also unlikely that badly finished discs and pads were supplied by Lexus.  It is possible that there is some restriction back to the master cylinder and it might be a good idea to change the brake fluid if this has not been done. If the front wheels are lifted off the ground and the brakes are applied with car powered up it should be possible to check how well the pads are easing off as the brake is released.

I don't think the OP can do much more than has been suggested already in this thread regarding thorough cleaning and greasing appropriate parts.  

The oscillation felt in the brake pedal is caused by the slight movement of the pads as these go over the built up pad material deposited on the disc which can pass backwards and forwards between the discs and pads in an increasing way.  We know discs do wear away but only slowly where everything is properly set up and working smoothly.

Many years ago I had dragging brakes on and old Fiat. Under pedal pressure the brakes were working but dragging.  I took everything apart and on cutting the  flexible rubber pipes to the calipers found that these had swollen to the extent that they hardy allowed any brake fluid  in to the caliper and none was returning, leaving the pads permanently rubbing the disc.  I wouldn't expect this to happen nowadays, particularly on a Lexus but it does show how important it is that the pads are free to move away from the discs without restriction.