[Alex e92]

Hi all, been on this forum for a while now but only just got around to making an account as I thought I would like some opinions on a current issue.

I have got a 2009 e92 335i which I've had since the start of July, now I got the car checked over by a friend that works for a BMW main dealer just to make sure everything was 100% as me and one of my mates who has a 2006 e90 335i went down to the Nurburgring at the start of August which is where this braking issue first occurred.

Now what happens is when the brakes get hot either on a track or either a fast drive down a B-Road there is a awfully violent steering wobble when braking, the harder you brake the more violent it is and when the brakes are really hot it can even be felt through the whole car. There is no pulsation that can be felt through the pedal at all. Obviously only just buying my car I'm not sure how old the discs and pads are but the pads on the front look fairly new (idrive reads 80k left in them). The odd thing is my friends car which had brand new EBC ultimax discs and yellowstuff pads fitted to the front of it before we left has exactly the same problem, if not more of a wobble than my car.

Now I suspect the issue is coming from the front brakes and it is that potentially that the discs are warped but what I don't want to do is replace them and then the exact same problem occurs again. Ive read some people have had issues with control arms but I want some peoples opinions or if anyone has experienced the same or similar issue before?

[old grey steve]

Vibration could be a number of things: It could be anything but the popular options lie below

1/ seized calliper(s)steering wheel will in essence shake up/down when brakes are applied
2/ distorted/warped discs again you'll get a general vibration due to run out o the disc(s) perhaps the most common assumed issue
3/ disc(s) are lipped, worn, corroded and have over time due to inefficiency suffered or due to the above perhaps have gone through an abnormal heat cycle(check your discs to see if they are scored or discoloured-if they look blue or god forbid even red then that'll tell you what you need to know.
4/ past tense but brakes when attented to in the past haven't been cleaned thoroughly before being re aseembled therefore items such as the sliders are contaminated with dirt which means over time one side may suffer more than the other for instance which would lead you to suspect a calliper issue.

Simple way to at least put you on the right path would be to spin each wheel to see if there is resistance when your trying to spin them by hand if you can barely turn the wheel off the ground with your hand then you're on the right track.

If your discs look like any of the items below both these items were for the bin




and once replaced custoemr had good brakes. In the first picture you can clearly see the blue discolouration

[Alex e92]

Thanks for your help on this!

Im going to get it booked in to be looked at and see what happens from there.

[ade146]

There is as much written about brakes on the internet as there is porn.

Its usually a pad imprint on the disc where someone has held their foot on the brake after they have come to a stop. This causes a high spot on the disc which in turn heats up more than the rest of the material.

Everything I have read suggests you can clean the discs up if it hasnt had time to change the molecular structure which it does over time.

In practice most garages just change them without really checking them.

Only once have I managed to clean the discs with a vibration after some heavy track use which did cure it. Most of the time I have given up and changed the discs. My rally car is prone to problems as you finish the stage with hot brakes and hold the car while time cards are sorted out. It gets used so hard that they clean up again. There is plenty of technical reading out there on this subject.

[Dan-]

My 335d sometime does this when hot during a track day or blast I'm running brand new M3 CSl 2 part discs (worn warp easily) and DS2500 Pads and can feel it if I have to slow from 155 to 30 or something after heavy braking, just learnt to live with it tbf

Would be interesting to see what is found out

[PAULDON]

Mine has exactly the same problem, when i get round to sorting it, the main culprit for this problem is when pads/discs have been replaced the fitter did not grease the sliders on the pad carriers. Causing the pads to brake unevenly, due to uneven pressure. 1/2 hour fix each side, just remove pads and grease sliding rods.

[Alex e92]

Thats an interesting response PAULDON and I am wondering whether mine will be something similar to that as I suspect the front pads were replaced not long before I got the car. I am going to get it looked at the start of October so will let you know how I get on Dan-.

[spirocheter]

I just posted on this issue with my 335d last week, with new discs and pads all round about ten months ago and less than 10k miles back. All Pagid components. No brake pedal pulsation, only noticeable from speed or heavy braking. Too dangerous to ignore, I'm having new front pads and discs fitted Monday coming. Not Pagid. I will be returning these to ECP to see if they'll honour the warranty. The discs aren't warped but have worn more closer to the bell apparently, mechanic thinks this is a manufacturing defect. He's fitting Durabrakes which his supplier warranty, we'll see how we get on!

[Alex e92]

To finally update this I have now had the chance to get this looked at. Only thing that was noticed was a slight runout on the front discs so I have had them skimmed and driving home tonight there was no noticeable 'steering wobble' like there had been. I now plan to change the current pads which I believe to be Pagids to DS2500's and then see how it goes.

[mob17]

Just make sure you bed them in properly

[Alex e92]

Getting the pads fitted on Tuesday and then the bedding in procedure will commence! Also managed to get hold of some Goodridge braided brake hoses so they will be fitted at the same time.

[Alex e92]

Just to update this if anyone is interested. I have since had front discs skimmed, new pads in the front and new discs and pads on the rear. I found after all of this the problem was still apparent. Since then I have had the front control arms polybushed and that seems to have solved the issue at normal road speeds. I will hopefully report back with good news after a trackday.

[djgandy]

Originally Posted by Alex e92

Just to update this if anyone is interested. I have since had front discs skimmed, new pads in the front and new discs and pads on the rear. I found after all of this the problem was still apparent. Since then I have had the front control arms polybushed and that seems to have solved the issue at normal road speeds. I will hopefully report back with good news after a trackday.

Should have just gone to M3 control arms. It's kinda good to see that these sort of problems are often the same issue, the crappy stock control arm bushes.

[mob17]

Originally Posted by Alex e92

Just to update this if anyone is interested. I have since had front discs skimmed, new pads in the front and new discs and pads on the rear. I found after all of this the problem was still apparent. Since then I have had the front control arms polybushed and that seems to have solved the issue at normal road speeds. I will hopefully report back with good news after a trackday.

Keep us updated.

The front control arms bushes going are quite a common problem i think.

[old grey steve]

Originally Posted by mob17

Keep us updated.

The front control arms bushes going are quite a common problem i think.

Indeed por road speed humps etc. seem to shorten their life poly bushing might well be a good move

[AWSAWS]

I wonder if tracking could also cause this? I'm on ecb slotted and dimpled discs with yellow stuff pads. Luckily I don't have the issue.

[Alex e92]

Just an update on this I have still got the wobble but it's now only when braking from around 90mph upwards. Now I have noticed I have got a slight steering wobble just when driving which is noticeable 70mph and beyond so my next step is to have all wheels checked for buckles and also all 4 wheels balanced.

Any other thoughts would be appreciated.

(all testing for this has been done off UK for anyone who thinks I go past the speed limit)

[Alex e92]

An update on this once again as I still have the ongoing issue.

This is now the list of steps I have taken in the attempt to cure it;

- Front Discs skimmed.
- New front brake pads.
- New braided brakes lines
- Front control arm bushes polybushed
- Rear pads and discs replaced with new
- New front outer track rod ends
- New rear outer track rod ends
- New rear toe inner and outer bushes
- New lower lateral arm inner/outer bushes polybushed
- New front drop links
- All 4 tyres replaced with non run-flat Michelin Pilot Super Sports
- All 4 wheels balanced several times
- Wheel alignment carried out at least 5 times

Also I have full AP coilovers fitted to the car but bare in mind that this issue started over a year ago now on what was a completely standard vehicle. Also the steering shake will only occur from high speeds, it does not occur or is not noticeable at lower speeds.

Any help or suggestions would be much appreciated.

[Aragorn30d]

have you actually replaced all four lower front control arms? Or just polybushed them?

Balljoints are probably worn.

[djgandy]

Originally Posted by Aragorn30d

have you actually replaced all four lower front control arms? Or just polybushed them?

Balljoints are probably worn.

Balljoint wear is quite common, hence most just replace arms with M3 ones.

[Alex e92]

They have only been polybushed, another thing that has been suggested to me is the front wheel bearings.

[mjn77]

I had something very similiar on my E46, next step was two new front hubs.