Warped discs

[KennyN]

My problem is that I have zero mechanical knowledge which is where these forums come in handy. I feel like I need to tell MB what problem they should be looking for which is obviously ridiculous but seeing as they have tried and failed twice to rectify it, 3 times if you count the brake changes before I bought it!!!

They reified the problem in October , the problem has returned some five months later.

At least now you know the issue seems to be with the front discs , which is a start.

There was a chap on the other MB forum that had a similar issue with his E-class (he is not the only one) , he tried numerous things to rectify the problem - front discs / hubs / calipers / pads / bushes etc , he ended up getting rid of the car as the fault always returned after time. I skimmed a set of newish discs for him and they were warped even after minimal mileage , the fault disappeared only to return sometime later , i never got a chance to check the discs again as he got shot of the car.

Your car is still under the 12m used car warranty period and well within the 12m warranty of the discs that were fitted in October , so IMHO you have a couple of options.

1 - Start the battle with the dealers , either the supplying dealer or the one that fitted the new discs in October.

2 - Buy a set of new discs (Brembo / ATE / Pagid) from the likes of ECP and have them fitted and see if the problem disappears straight away , if it does then move on. If it doesn't then refit the original discs and - Start the battle with the dealers , either the supplying dealer or the one that fitted the new discs in October.

K

 

[geoffus]

I skimmed a set of newish discs for him and they were warped even after minimal mileage , the fault disappeared only to return sometime later

Were the discs warped before you skimmed them?
They warped again shortly after ?
So the problem was the discs material, I would imagine it takes a lot to warp a disc during normal driving.

 

[KennyN]

Were the discs warped before you skimmed them?
They warped again shortly after ?
So the problem was the discs material, I would imagine it takes a lot to warp a disc during normal driving.

New discs were fitted , problem disappeared , wobble returned and i checked his discs and they were warped not by much but warped , i skimmed them and he refitted them and problem went away - only to return some months later at which point he was so pi$$ed off with the wobbly car and got shot of it.

K

 

[geoffus]

New discs were fitted , problem disappeared , wobble returned and i checked his discs and they were warped not by much but warped , i skimmed them and he refitted them and problem went away - only to return some months later at which point he was so pi$$ed off with the wobbly car and got shot of it.

K

Strange that both discs had warped for no apparent reason, if it had been one you may have said sticking caliper or hub bearing failure, but both ?

 

[KennyN]

Strange that both discs had warped for no apparent reason, if it had been one you may have said sticking caliper or hub bearing failure, but both ?

Very much so , both calipers were replaced along with the hubs from what i recall. It would need some seriously heavy braking to warp a new set on OEM discs especially on the road.

Seems odd that they are OK for a while once skimmed or replaced , then the wobble starts again a few thousand miles later ??

K

 

[tonysmb]

I've seen several reports of people stating that they experience brake judder several months after new discs have been fitted, often over a period of time and several sets of discs. I can't say I've been aware of it previously, over many years. What's changed?

Well, one thing is that many cars are now autos, have electric park brakes and/or 'hold' systems. As a result, many drivers now hold their cars on the footbrake, don't use the parking (old handbrake) brake whereas previously they would select neutral, footbrake off, handbrake on.

In addition, many people with autos are regularly using their brakes, certainly more so than with a manual. Are discs getting hotter (especially the front set) than used to be the case and then regularly being held on the footbrake (or 'hold' - effectively same thing), eventually creating hot spots and then slight warping?

I've tried explaining to several people (including younger family members) that holding a car on its footbrake when the brakes are hot is not a good idea but it doesn't seem to register, especially when they're too busy using their 'connectivity' systems to think about the actual car.

I'm not saying this is the problem but it might well be a factor.

 

[Petrol Pete]

I too have heard what tonysmb ^^ Has heard . brake 'wobble' disappears with new discs/pads only to return a few thousand miles later. I have never encountered 'warped discs' on any car I have ever owned and personally I do not actually believe it even exists on a modern road car that has been driven normally .

Getting a (for example) 11 Kg, 345 mm Brembo cross drilled ventilated disc to warp during normal road use would (IMHO) take some doing.

Just my opinion , of course.

 

[sgregory124]

I've seen several reports of people stating that they experience brake judder several months after new discs have been fitted, often over a period of time and several sets of discs. I can't say I've been aware of it previously, over many years. What's changed?

Well, one thing is that many cars are now autos, have electric park brakes and/or 'hold' systems. As a result, many drivers now hold their cars on the footbrake, don't use the parking (old handbrake) brake whereas previously they would select neutral, footbrake off, handbrake on.

In addition, many people with autos are regularly using their brakes, certainly more so than with a manual. Are discs getting hotter (especially the front set) than used to be the case and then regularly being held on the footbrake (or 'hold' - effectively same thing), eventually creating hot spots and then slight warping?

I've tried explaining to several people (including younger family members) that holding a car on its footbrake when the brakes are hot is not a good idea but it doesn't seem to register, especially when they're too busy using their 'connectivity' systems to think about the actual car.

I'm not saying this is the problem but it might well be a factor.

I think this is spot on. Stands to reason that braking from high speed to a stand and holding the car on the brakes for a period of time (i.e at lights etc) cannot be good for the two surfaces, leading to pad material potentially transferring to the disc and causing judder afterwards, unless cleared with a good few long hard braking runs from high speed.

 

[Bellow]

I've tried explaining to several people (including younger family members) that holding a car on its footbrake when the brakes are hot is not a good idea but it doesn't seem to register, especially when they're too busy using their 'connectivity' systems to think about the actual car.

Back when rally drivers used to have to stop to collect a time card at the end of a stage they always sat without the brakes being applied. Eliminated the possibility of warpage and pad deposits on the disc.

Vented discs are centrifugal air pumps and don't offer much cooling at slower speeds. In the cut and thrust of city driving it isn't difficult to put heat into brakes then say, come to a sudden halt for say, an unexpected red light - then sit there with the brakes on. A bit of pad deposited there, some motorway work where the high spot of the deposit keeps brushing the pad and adding to it - and it isn't long before there's enough to create a judder.

Apply brakes firmly when needed and only when needed. That's how Walter Rohrl lapped the 'ring in a Porsche 911 variant that no amateur could complete the lap with without fading the brakes.

 

[geoffus]

I remember my old escort R/S Turbo getting brake fade around Olton Park on a track day, discs got so hot they were nearly glowing, Drove home afterwards and no hint of a wobble or warp, one chap in a cosworth had his brakes actually on fire. Wobble and warp must be a new thing on Mercs.

 

[Bellow]

I used to traverse the Cairn O Mount and arrive in Banchory with discs that were dark brown when they'd cooled. No juddering.
I suspect the current issues people are having are related more to sitting stationary than when in motion.

 

[jaffajim0]

MB selling dealer picked the car up and checked the hubs and the callipers and found no problem. Said the discs were slightly warped and blue which indicates lots of motorway miles and heavy braking. I’ve not had the car a year yet and only done just over 8k miles, 8”0% local, and I HATE heavy braking so that is not the issue. They’ve changed the front discs, “as a goodwill gesture" which I assume means don’t bother coming back if it recurs!!
I no longer use the hold button and now select P when I have to stop but if that was the cause I imagine there would be many more drivers complaining of this issue and surely somebody in MB would be putting my right, no??
To be honest if it does recur I shall just get shot of the car and assume I’ve got an unlucky one and get another which is what I want to do not but I can’t find the same model within my price range.

 

[DSM10000]

MB selling dealer picked the car up and checked the hubs and the callipers and found no problem. Said the discs were slightly warped and blue which indicates lots of motorway miles and heavy braking. I’ve not had the car a year yet and only done just over 8k miles, 8”0% local, and I HATE heavy braking so that is not the issue. They’ve changed the front discs, “as a goodwill gesture" which I assume means don’t bother coming back if it recurs!!
I no longer use the hold button and now select P when I have to stop but if that was the cause I imagine there would be many more drivers complaining of this issue and surely somebody in MB would be putting my right, no??
To be honest if it does recur I shall just get shot of the car and assume I’ve got an unlucky one and get another which is what I want to do not but I can’t find the same model within my price range.

The dealer is talking "round objects"!

I hope it fixes your problem but part of me thinks not.

Good luck anyway

 

[JHS]

Back when rally drivers used to have to stop to collect a time card at the end of a stage they always sat without the brakes being applied. Eliminated the possibility of warpage and pad deposits on the disc.

Vented discs are centrifugal air pumps and don't offer much cooling at slower speeds. In the cut and thrust of city driving it isn't difficult to put heat into brakes then say, come to a sudden halt for say, an unexpected red light - then sit there with the brakes on. A bit of pad deposited there, some motorway work where the high spot of the deposit keeps brushing the pad and adding to it - and it isn't long before there's enough to create a judder.

Apply brakes firmly when needed and only when needed. That's how Walter Rohrl lapped the 'ring in a Porsche 911 variant that no amateur could complete the lap with without fading the brakes.

Exactly how I have always used my brakes, even in the days of drums all round. Never had a warped disc or cracked drum.

 

[BlackC55]

These "lightweight" discs are a PITA.

There is a very specific fitting procedure with them. If you don't follow it they will warp.

 

[Tsb1983]

Had a similar issue back in 2017 - dealer changed discs and pads and was fine after. I think it’s best to do discs and pads at same time personally.

 

[keith of kent]

Perhaps the problem is caused by rust between the disc and hub pushing the disc slightly out of line. The rust perhaps being caused by acid wheel cleaner used by hand car washes.
Many cars have rusty caliphers/discs that I think is caused by this. Our MB's are 4 & 7 years old, no rust but washed at home without alloy wheel cleaner

 

[chic0821]

Said the discs were slightly warped and blue which indicates lots of motorway miles and heavy braking.

Motorway miles does not cause overheating as you hardly ever use the brakes. You say you don't do heavy braking which then suggests that a piston is sticking keeping a pad against the disc which will cause overheating & blueing. Also any competent garage can do brakes. They all work the same on all cars, Mercedes aren't magic, (there is a sequence for winding back the parking brake) but decent garages know this so you don't need a main dealer or indi

 

[geoffus]

These "lightweight" discs are a PITA.

There is a very specific fitting procedure with them. If you don't follow it they will warp.

Special procedure? Can you elaborate? I thought you just cleaned the hub and slide them on, tighten the disc screw and the wheel holds them tight and square ?

 

[colinallcars]

Special procedure? Can you elaborate? I thought you just cleaned the hub and slide them on, tighten the disc screw and the wheel holds them tight and square ?

Hope you’re right, I’ve been doing that for years and never had a problem with warping!