Front brake discs warped W212 E220

[Craiglxviii]

Well, my first experience of the wonderment that is MB Customer Services.

As some of you know I had to have a full brake disc & pad change in the last week of July, 5 months and 5000 miles after taking the car over.

MB were unable to book me in and this was 2 days before our French road trip was due to start, so I called around, found a local brake shop who could get the parts in and do the job, and shelled out £300 to get it done in time.

Reported to MB on our return who promised to look into it, just had the call.

"We ascribe this to normal wear and tear and are not willing to offer a refund. Brake discs warp due to being repeatedly heated and cooled as pressure is applied to the brake pedal."

Well, no sh1t Sherlock. In 5000 miles? I don't think so.

This is their final decision too so I'm happy to request an independent investigation. They aren't even willing to look at the damn parts.

Advice please, gents? Anyone had anything similar recently?

 

[PovertySpec]

"We ascribe this to normal wear and tear and are not willing to offer a refund. Brake discs warp due to being repeatedly heated and cooled as pressure is applied to the brake pedal."

Is right though. Depends on the braking style. Brake hard = generate heat. Repeat frequently = potential to warp although you don't expect it on a Merc.

Read the road far enough ahead and brake discs and pads last ages.

How old were the discs and pads when you took over the car?

Maybe the previous owner was a serial brake abuser?

 

[Craiglxviii]

Is right though. Depends on the braking style. Brake hard = generate heat. Repeat frequently = potential to warp although you don't expect it on a Merc.

Read the road far enough ahead and brake discs and pads last ages.

How old were the discs and pads when you took over the car?

Maybe the previous owner was a serial brake abuser?

Sorry, to clarify.

The car was built in Nov '15. I took it on from new with only 280 miles delivery mileage in Feb '16. Originally-fitted brake discs, and I'm not a heavy-braking driver.

If it was a used car then I would ascribe it to wear and tear, but the fact that I've had it from new, it's only 10 months old anyway and that this happened on about 5300 miles total distance travelled leads me to point to quality problems at the brake disc end.

 

[PovertySpec]

Sorry, to clarify.

The car was built in Nov '15. I took it on from new with only 280 miles delivery mileage in Feb '16.

O I C.. Sorry, 5k seems very low.

Small claims if you're already at deadlock.

 

[DREAMER NO2]

Not on .I have only had this once in all my years of repairing cars. Running a small time garage just for friends over time. And that was once i fitted set of discs on my own Volvo 740 .And after a few weeks it had both the front discs warped .Reason i went on a long trip before this , and on my return i washed the car down with cold water. From then, i had the problem .

 

[daibevan]

5000 miles & 10 months? Pathetic

 

[Craiglxviii]

O I C.. Sorry, 5k seems very low.

Small claims if you're already at deadlock.

What MB don't know is that I have access to the OEM customer warranty faults database, so I am pulling the claims made against them for warped brake discs off now.

If they want to I'll happily see them in court.

 

[PovertySpec]

Last time I experienced warped discs was on a Fiesta in the mid 80's, got them skimmed for £10 each.

If they want to I'll happily see them in court.

Don't think it would get that far once they saw the particulars of claim and you'd paid the fee.

 

[malcolm E53 AMG]

Not very good is it Craig!

In normal driving you would expect at least 25K miles from a set of discs and some a lot more.

At 5K miles there is obviously a fault somewhere as you don't 'race and rally' the car, the problem lies either in the tolerances in manufacture or metal content. Unfortunately most manufacturers get away with fobbing the general public off with tales of normal wear and tear so stick to your guns and I'm sure you will get a reasonable result.

The only complication being that you incurred £300 of expenditure on replacing the original discs before MB could inspect them so a good job you kept the offending items.

Good luck with the claim!

 

[Craiglxviii]

Not very good is it Craig!

In normal driving you would expect at least 25K miles from a set of discs and some a lot more.

At 5K miles there is obviously a fault somewhere as you don't 'race and rally' the car, the problem lies either in the tolerances in manufacture or metal content. Unfortunately most manufacturers get away with fobbing the general public off with tales of normal wear and tear so stick to your guns and I'm sure you will get a reasonable result.

The only complication being that you incurred £300 of expenditure on replacing the original discs before MB could inspect them so a good job you kept the offending items.

Good luck with the claim!

Deliberately so, yes. I had already told my local stealership that I'd be keeping the parts as they couldn't give me a spot to have the car in for inspection until the week after I was due to return, and no way was I going to drive 2000 miles with warped discs. They're sat in the garage now along with the pads. They couldn't actually give me a date to do any work on the car, you understand, just to inspect it first.

Just not good enough.

I had half expected the fobbing off, but at 5000 miles it's a bit fishy. I'd expect 25-30k, I'm used to getting discs changed every 15-18 months or so.

So I guess it's report run, then court fee time.

 

[hotrodder]

Brake discs don't warp. Read this thread http://forums.mercedesclub.org.uk/showthread.php?p=1224778#post1224778 and then google brake DTV... i posted several links to articles on the subject in that (and probably other threads about "warped" discs), the links may be broken but pretty much every single brake manufacturer in the known universe has published countless articles on the subject so it shouldn't be hard to find a bunch

If the [strike]mechanic[/strike] fitter diagnosed warped discs by measuring runout then they achieved nothing as a single DTI cannot tell the difference between runout caused by rust/grit between mounting faces, rusty hubs, uneven disc wear/uneven pad deposits causing thickness variations or a lump of cast iron that has physically warped like a buckled wheel (not something cast iron likes doing without cracking). All a DTI can do is quantify runout which is most useful after fitting new discs because if it's excessive DTV is likely develop about 3 - 6000 miles later.
A decent (i.e. resolution of 10ths of a thou) micrometer is the simplest way to check for/confirm disc thickness variation albeit fairly tedius as you need to take loads of measurments

 

[Craiglxviii]

Brake discs don't warp. Read this thread http://forums.mercedesclub.org.uk/showthread.php?p=1224778#post1224778 and then google brake DTV... i posted several links to articles on the subject in that (and probably other threads about "warped" discs), the links may be broken but pretty much every single brake manufacturer in the known universe has published countless articles on the subject so it shouldn't be hard to find a bunch

If the [strike]mechanic[/strike] fitter diagnosed warped discs by measuring runout then they achieved nothing as a single DTI cannot tell the difference between runout caused by rust/grit between mounting faces, rusty hubs, uneven disc wear/uneven pad deposits causing thickness variations or a lump of cast iron that has physically warped like a buckled wheel (not something cast iron likes doing without cracking). All a DTI can do is quantify runout which is most useful after fitting new discs because if it's excessive DTV is likely develop about 3 - 6000 miles later.
A decent (i.e. resolution of 10ths of a thou) micrometer is the simplest way to check for/confirm disc thickness variation albeit fairly tedius as you need to take loads of measurments

What I know is this:

No problem at all for the first 5000 miles.
Over the space of 2-3 days we noticed that the car began juddering during light braking at high speed only.
Replacement brake discs and pads fitted and the problem has gone.

Now there had been some question over whether or not the wheel was buckled due to hitting a pothole, this turned out to not be the case. The tyre sidewall was gashed but no buckling of wheel. The juddering did not present itself at low speeds, or high speeds, but only under braking.

I'm familiar with the metallurgy of cast iron and its propensity to crack under thermal loading cycles.

I wouldn't bother with a micrometer, I'd just ask a local engineering firm to run their laser CMM over the disc instead. £50 to save an afternoon's work.

Whatever the actual cause of the problem is, it doesn't take away from the fact that it shouldn't have happened to a car of half a year of age and under 5000 miles of total distance travelled from the moment it rolled off the line.

 

[hotrodder]

I'm familiar with the metallurgy of cast iron and its propensity to crack under thermal loading cycles.

CI isn't especially prone to cracking from thermal cycling, if it was it wouldn't be used for cookware, fireplaces, traditional ranges, radiators and so on. What i said was it doesn't like being bent/physically distorted without cracking. Whether the strain is the result of physical stress or a large thermal gradient resulting in uneven expansion

Whatever the actual cause of the problem is, it doesn't take away from the fact that it shouldn't have happened to a car of half a year of age and under 5000 miles of total distance travelled from the moment it rolled off the line.

Agreed. Don't expect to have problems with a new car, household applience, telly or whatever but $h*! happens hence warrenties and Sale of Goods act etc. How problems are dealt with is the important bit which is where it usually goes properly wrong. You were spun a load of utter nonsense by MB and they (along with many others in the motor trade) get away with it because people STILL believe brake discs "warp".

A bicycle with a buckled wheel doesn't get brake judder because when one brake pad is being pushed away the other is being pulled in. If a brake disc physically warped without cracking it would NOT cause a brake judder for the same reasons, one piston(s) is pushed back into the caliper at the same time and rate as the other side is free to slide further out. If the 'buckle' is bad enough for the disc to constantly touch the pads in the same spot(s) each revolution then eventually that can lead to uneven wear which brings us to

If one or more spots on the disc are a tiny (seriously, talking tiny numbers) bit thinner (or thicker due to uneven pad deposits) then when the pads run over the high or low spot it's gonna be felt through the pedal as brake fluid is obviously incompressible. Same thing can happen with a bicycle if the rim gets dented, had this the other week with my road bike. Dunno how it happened without the tyre getting damaged but was getting a judder/pulsing through the brake lever until i knocked the dent out of the rim

Probably never gonna find out if there was a burr or some grit that got missed when the car got assembled or if the disc was out of spec but if the disc runout was slightly excessive then the after a few thousand miles a couple of spots on the disc are gonna end up microscopically thinner which, when the 'step' gets big enough is gonna manifest as a judder. Uneven pad deposits can result in the same thing but can often be fixed by using the brakes properly i.e. several repeated hard applications
If the excessive runout is down to a hub with too much runout (whether it's badly made or, on older stuff, rusty) then fitting new discs will only fix the problem for a few thousands miles before the cycle repeats and i have to rant about the myths of "warped" discs again

Probably be an utter waste of time (like trying to proove there was something wrong with a clutch and you weren't slipping it excessively etc) but personally my approach with MB would be to throw their "discs warp" statement back at them... like i said pretty much every single brake manufacturer in the known universe has published countless articles about disc thickness variation, what causes it and how to prevent it

 

[EmilysDad]

Cheap materials is my guess. I replaced discs with pattern on AN Other car years ago, within 3/4000 miles they were 'warped'. Rather than replacing both (due to being as new), I just replaced the one disc I had problems with, and again had a 'warped' disc within a similar mileage. Sold a kidney & paid Vauxhall to replace them both and never had another problem. Supplier of pattern discs were not interested .... apparently I'd fitted them wrong.

I know it's not quite the same as your case Craig as your discs were new on a new car, but it does seem to point to crap (ie cheap) parts fitted in the first place.

 

[om613]

The buckled bike wheel analogy is a very good one.

My car came with recently fitted discs and pads. The vendor said they'd buckled.. It had only done a few hundred miles from the look of things.

I cleaned the hub faces, properly, not just a wipe over, and the vibration had gone.

 

[PovertySpec]

personally my approach with MB would be to throw their "discs warp" statement back at them

For £300 and all the aggro going small claims my personal approach might be to make a statement and throw their "warped discs" through their nice expensive glass front door at 4am wearing a boiler suit and a bally

Only joking!

 

[erickh]

5k is not realistic. I would expect at least 15k to 20k for a Mercedes part. Mine still going, and I'm been driving over 34k

 

[Craiglxviii]

5k is not realistic. I would expect at least 15k to 20k for a Mercedes part. Mine still going, and I'm been driving over 34k

Yes, as I said before my old Golf would do 40k to a set with no problems at all and I'm sure did more than that, I'm remembering 6-7 years back now.

 

[erickh]

Yes, as I said before my old Golf would do 40k to a set with no problems at all and I'm sure did more than that, I'm remembering 6-7 years back now.

Any luck getting it replaced by Mercedes?

 

[television]

I spent some time in the engineering field, We could have a cast iron bed that had a minor fault, put it on the surface grinder and the whole thing could twist.

Cast iron heads can and do warp, or go out of true.

The same goes for brake disc, they can be fine when made, you do a few k miles and the surface wears down,and a stress point is relived and it goes out of true.