Vibration when braking

[cws196]

I've noticed over the previous 2weeks that I'm getting a rumbling sensation/slight judder when braking - when you press the brake pedal it's a feeling akin to driving over small rumble strips! The problem starts when braking at over 40mph, is worse the higher the speed and is most noticeable on a smooth road. You can feel the vibration very slightly through the brake pedal and steering wheel.

- ATE pads and (drilled) discs on the front, last replaced in Dec2013, vents holes are clear/no corrosion/no bad scoring/no pronounced lips on the discs and good pad life

- original pads/discs on the rear (mileage is 128K) but pads and discs look fine ie no corrosion, scoring, pronounced lips etc.

- wheels are not getting hot ie no obvious signs of caliper binding

- no appreciable suspension play, knocks or clunks

- tracking all seems fine

I've attached a picture of the driver-side discs, front and rear.

Any ideas.....?

 

[nsiddiqui]

vibration whilst braking is usually a warped disc. It also makes sense for it to be a warped disc if the faster you go the more the vibration when braking.

 

[RichardF]

You need to check the inside face of the disc/pad also. Often worse where you can't see it.

 

[paulshep69]

You need to check the inside face of the disc/pad also. Often worse where you can't see it.

Just replaced mine because of exactly this. My car sits for 2 weeks, whilst I'm away offshore. The discs looked fine on the outer face but were badly corroded on the inner face. Well worth a check as Richard says.

 

[cws196]

Thanks all.

The car is sat around most weekdays now so the above all figures. Seeing as the discs/pads appear to have plenty of life left yet (ie pad thickness is good and the discs are not badly 'lipped') I may investigate the cost of getting them skimmed.

 

[grumpyoldgit]

Looks like you have the bigger 330mm sports discs on the front. Bear in mind that the thickness of new discs is 28mm and the minimum 'advised' thickness is 26mm.

 

[whitenemesis]

I would try a few 'emergency' stops from high speed before anything else. Sometimes glazing and/or pad deposits can cause a vibration.

Does anyone skim discs any more? Can't be cost effective, new discs aren't that expensive..

 

[cws196]

Googled and found several places who will skim discs.

.....I'll try a few emergency stops!

 

[KeithJG]

When i bought my motor 30 months ago it had aftermarket discs and pads all round fitted by the previous owner. Although they had only done a few thousand miles there was a vibration from speeds above 60mph when braking fairly hard.

I had new Goodyears fitted all round (which replaced supposedly high end Budget tyres) which did seem to help but i don`t like feelings like this with a quick motor so today i have just had all discs and pads replaced with Mercedes parts which was actually kit 954 Equipment Package as per spec. of my motor. The parts were just £284 including courier from Newcastle.

I could not get down to Olly`s this month so they were fitted local, really pleased with the work.

When out on the road the difference is really startling, no vibration and the brakes even after 20 miles feel superb and powerful.

Why owners use cheap fuel and aftermarket parts for their prize Mercedes i will never know?

 

[David404]

Why owners use cheap fuel and aftermarket parts for their prize Mercedes i will never know?

Agree entirely. Always been of the opinion that ultimately the cheapest way to maintain a car is to do it right.

I bought my W211 because I want to feel like I'm driving a £35k-£40k car but on rather less money. I let somebody else drive my car for 7 years and 65k miles in return for a 75% discount. But I still want it to look and feel like it did when new.

 

[E55BOF]

Why owners use cheap fuel and aftermarket parts for their prize Mercedes i will never know?

Perhaps it's not their 'prize' Mercedes; perhaps it's just a car at the end of the day.

I agree on the fuel; I use Momentum or V-Power petrol, because I persuade/delude myself that they will have good additive packages in them.

However, I have Bosch pads and ATE discs on the front of my 55K; they work very well.

I fear that any sense of superiority you may feel because you never use aftermarket parts is both illusory, and deluded. A (genuine) OE-spec Bosch/Pierburg/Mahle/Jurid/Whatever part in the manufacturer's box is the same part as in a Mercedes box. Mercedes would like you to buy theirs, of course, but this is business, not tender solicitous concern for you or your car.

Using only OE parts will no doubt pay dividends when you come to sell the car, but I don't fret about what my cars will be worth when I sell them, and I don't look after them so somebody else can enjoy them after me; I look after them for my own enjoyment.

It's just a car...

 

[brucemillar]

Mercedes do not make discs, pads or shoes. Therefore you are always buying aftermarket parts. Some people like the feeling that owning the Mercedes Logo on the box that their aftermarket parts come in, gives them. That logo tends not to enhance braking distances.

Mercedes parts are built to a specification. Before you start to feel good about this? So is the steel that they make their body panels from. History tells us that Mercedes managed to clone (and some say better) the fast rusting process. To counter this and to make you feel better they gave us the 30 year paint warranty. To get the wording correct they employed Bill Clinton's speech writer then had it proof read by Morecambe & Wise.

 

[Mr Kripling]

Most "warped" discs are usually due to lack of cleaning of the wheel bearing face which then results in excessive run-out of the disc. Over time, this leads to uneven wear on the disc which then eventually gives rise to increased judder.

As a result, it's more likely that the installation was the problem rather than the aftermarket parts.

 

[brucemillar]

I am told, that "warped" discs are very unusual. What you do get is "Disc Flutter" and that is usually caused (as Mr Kipling states) by poor preparation of the surfaces at installation. Once the disc has become worn, due to flutter, it is too late to correct it by grinding or extensive braking, even if you have now corrected the dirty faces.

The feel of flutter is no different to warping! but modern manufacturing makes warping unlikely. Add to this the fact that most road cars will never generate anything like enough heat to warp a disc and you have an urban myth in the making.

Cross drilled and mahoosive calipers, are fitted for looks rather than improved stopping distance. There is mechanical equation that disproves the theory that cooler discs and bigger pads will actually slow you down any quicker. To do this you need carbon discs and massive temperatures (see F1 for some clues) to achieve this on a road car you would have to sit with your foot on the brake whilst driving and even then would be unlikely to generate enough heat through a steel disc to make a noticeable improvement.

 

[Mr Kripling]

Big brakes only really make a difference with higher speeds and larger/stickier contact patches for the tyres. If you can engage the ABS by stamping on the brakes at a given speed in a car, larger brakes will make virtually no difference to braking performance.

As for ceramics, the main reason they're used in racing is their lower weight. They don't provide any extra resistance to fade over steel discs and, on road cars at least, are mostly a marketing job.

 

[RussM]

I'm not sure if it's related, but after buying my w204 c350d I noticed brake judder from the front.

It's got the auto engine stop and 'hold' function, whereby once stopped if you keep your foot on the brake a little harder, the engine stops, if you press it harder still the brakes come on and stay on so you can take your foot off the brake.

Which in theory is a good thing except I'm not convinced if this is done repeatedly then you'll be putting heat into the discs at the pad contact point when stopped (from the hot pads) and could affect their run-out?

Anyway they were replaced under warranty after just over 7,000 miles from new, I don't use 'hold', never have, but the previous owner may have or the guy that drove it up from the London dealership. Just my 2p.

 

[zenman63]

The brakes I my ML63 had just been changed before the guy sold it to me, all looked very new and when I test drove it felt fine but on the way home from Southampton braking from speed it vibrated badly.
First job was strip the brakes to see what he had done, stared at the front and the hub face was ok, rears needed the park brake adjusting and that was when my son suggested clocking them with a dial gauge.
Rears were spot on and the one front I had apart and cleaned also good, the last front we just clocked was off the scale and went all the way around the dial!
We pulled the calliper and disc off only to find on one side of the hub polished black rust a large crust of it, so cleaned the face up and the inside of the disc and it now clocks fine as the others.
Road test however still vibrates but so much better and improving all the time.