DaveK

Just seemed to have started this morning. If I brake (and doesn't even have to be very hard) the steering wheel starts vibrating (actually, it's trying to turn itself a few degrees in each direction, but I guess this is what people call vibration).

I checked that the wheels were fully bolted on when I got home but haven't had time to do much else. Tyre pressures look OK - probably not perfect (can't remember when I last checked them) but they are certainly not too low.

Since it seems fairly sudden (never noticed it before) I wonder if I've just lost a wheel weight. I had the wheels refurbed at the service in May - and I guess they must have removed the weights / rebalanced. I'll pull the wheels off when I get the chance and take a look - but if it's not that, what else could cause this?

Andy Roe

As it's only happening under breaking, have a look at the brakes - warped or cracked discs perhaps? Loose caliper/pad?

DrJupeman

Does it happen when you brake harder? Generally a warped feel, which is often really uneven pad transfer to the rotors, is most noticeable under light pedal pressure. Truly warped rotors will feel worse under heavy braking.

SimonExtreme

The one thing I will guarantee you that it isn't is warped brakes Now, where is the hobby horse icon as I am about to climb on mine

I have researched the issues arround alleged "warped" disks for a long time because it is a problem that plagues Mitsubishi Evo's. In simple terms, the diagnosis of "warped disks" is given to a host of problems that are not the disks warping.

Rather than me, a nobody with no proven experience go on about it, this link is one of the best about this subject.

Warped Disks?

Based on this and other articles, I did a systematic study of warped disks in Evo's and can honestly say I have never seen a warped disk. Furthermore, I have never seen a warped disk on any car or even a race car. In every case I have looked into (literally 100's), there has been another explination.

SimonExtreme

Dave

As to your problem, a few things spring to mind. The fact that it came on suddenly and the other info given, I would suspect wheel weights as you have. Wheel balancing is something that isn't just about the weights. Have you kurbed the car recently?

Going on from there, have you changed pads or disks recently. If not, I doubt it is related to that. I might be concerned about bearings but I would assume you aren't hearing any bearing type noises. I am not sure what could make the run out on the disks change, but that is another source of the vibrations.

Its a shame I am going away in the morning because you must be fairly close to me (Surrey) and I would have been happy to meet up and take a look. If you haven't got it sorted in 2 weeks, let me know!!

jeffnudd

First of all i would simply go up and down the road several times and do some good braking, when the brakes warm up the vibration should get worse if there is a disc problem.

I that situation i would got to a garage and borrow their brake tester for five minutes and see if there are fluctuations on the front brakes.

I have had vibrations before like yours and found a tyre had gone out of shape. (Buldged), i know your going to say yes only under braking but it was the problem, changed the tyre and everything was ok :-)

garrett376

Usually new brake rotors cures this problem - if you look at your rotors, they are likely at or very near their wear point.

Michael Delaney

Here we go. The brake rotor/pad wear wars are about to begin. Gentlemen, let's keep it civil.

Bearclaw

I bought into this and tried "seasoning" the new rotors and pads on another car exactly as described in the article, and guess what I still got later on? Something that walked like a duck, quacked like a duck - and vibrated like a warped rotor. And new rotors cured it. So call me "Stoptech Skeptical".

garrett376

Barry were your rotors near being worn out? They seem to act that way when worn out... whether they're warped or not, who cares because they need to be replaced anyhow!

Bearclaw

On the Volvo that I tried this on, the rotors had one cut on them but still had plenty of meat. I had the warpage show up a few thousand miles later. I tried this on a Camry as well, Toyota had an inherent design problem with their rotors (too thin - my view), I re-bought new rotors more than once because of it, but my complaining fell on deaf ears. But that technique didn't help or prevent anything as far as I could tell.

Larry Herman

Every time, and I mean EVERY TIME that we have had pulsing problems with brakes, it has been pad related. Even the over-worked, under-cooled Mitsubishi EVO 8 that we had and went nuts trying to fix the vibrating brakes (like SimonExtreme) was finally cured by changing to Pagid RS-19 pads. For those of you who like to change rotors, be my guest. I only ever have to change mine when they are completely cracked and worthless. Those who understand this know what I mean. First shot fired!

Euromagination

pad transfer...

have experienced it on a few cars, most recently my Evo VIII (just like Larry H. above) as the stock pads were quick to melt over (aka transfer) to the rotors when hot and stopped; thus creating a high spot on that part of the rotor. once the high spot is created and hardened onto the rotor, the pad will run over it upon each pass from there on out and create a vibration.
i have since changed pads and rotors and the problem is gone. machining the rotor surface will turn out to be only a temporary solution to the problem because you will still have the same offending pad/rotor combination. only real solution is to change the pad as Larry says above. or you can do as i did and change the entire pad and rotor combo.

definitely not a warped rotor. that's pretty much bs except for extremely rare cases; no offense to anyone.

Bearclaw

No offense taken. Maybe my problems warrant further investigation, sounds like I'm blaming the wrong component. I bought factory pads for the Camry. I bought some good aftermarket stuff for the Volvo. Maybe not good enough.

That's why I come here - for enlightenment.

And good fellowship too, of course.

SimonExtreme

I know it's a controversial subject but having been involved with Evo's for years and had this problem, a few of us decided to look at it once and for all. I am going to slightly disagree with Larry. I never went nuts over it because I knew from day one what the issue was and always used agressive pads to "clean" the disks. However, you get so amny sceptics that I looked at it a lot further.

On the Evo, the broblem is the Brembo disk material. It is possible to cure the problem with different disks, as well as agressive pads. Seen under a microscope, the Brembo disk metal has more fissions than .............. well, you wouldn't believe it. Some disks seem to have more holes in the surface than surface! It is into these fissions that you get the build up and why it comes back and back and back. All disks have these fissions (even carbon disks!), its just some are more significant than others.

I hadn't realised that this was such a hot topic here! Frankly, I don't care any more if people believe it. If they want info/advice, I will provide it. If they listen, they will save money. If they don't, why should I get upset.

Bearclaw - I use the Stoptech link because it is the easiest way to post information on the subject. I could have posted a link to a thread that I think you can still access on the MLR website but it runs to about 30 pages and winds all over the place. Or I could have tried to paste and copy various other things I have or even scan it. However, I honestly had so much of this over the last 5 years that \i really cannot be bothered by the arguement.

I did, however, recently read an item by a top race engineer who supported the deposit side of the arguement but did say that he had actually seen 2 warped disks in his time. But he had been in racing for about 35 years! So maybe we are all wrong and it is a common occurance