BMW E39 brake judder where to start??

[boingboing]

I have a year 2000 BMW 523i E39 that is suffering from brake judder.

I get the judder at any speed when braking, not just at high speed, the car does not see to shimmy at 50-60mph that I have read about on this site, or pull to one side if I take my hands off the wheel

The car has just passed an MOT and I did ask them to check the bushes on the front but no problems were found.

So where do I start, I have not owned the car to long and has had M series alloys and brand new tyres fitted by the previous owner.

[ShineOn]

My first thought, as it is only when braking, is a warped front disc (or indeed, a pair of warped discs).

[boingboing]

Thanks ShineOn as that is my thinking also.

Just that the discs and pads do not look that old on the front and still look to have plenty of life in them but will replace them anyway and see what happens

[Peter]

You do mean juddering felt through the steering wheel, not juddering through the pedal, without steering wheel judder? Pedal feel only, look at the rears.

Could still be suspension wear on the E39, as many cars pass the MOT and still need new parts to cure judder.

Even if it is discs, it can be the mounting on the hubs wasn't good, causing a bit of run-out. E39 cars require attention to detail on assembly, as one little error will be amplified, as it does for shimmy.

Peter

[wreeve]

My money would be on suspension. I've taken off bushes which look perfect but replacement cured brake judder.
I would go for replacing the traction arm bushes first and see what happens.

[cocovs6]

I have a similar issue with brake judder on my 540i.When applying brakes lightly I get a bit of judder tends to be worst around 50mph.However when braking harder no judder evident.

Probably down to disc not sitting perfectly on hub or even build up of crap on your brake pads which then can be transferred to discs which many people then called warped discs.

It seems to be more of a problem with autos as they are constantly sitting with brakes on unlike manual cars so any heat on discs can lead to a deposit being left on disc from pads.

As other members have mentioned replacing front bushes may cure this but in my case actually made judder more noticeable.In the end pair of front shocks and wheel alignment cured most of the problems.

[wreeve]

My theory about the judder is that the suspension and bushes are designed to iron out all the little imperfections and tolerances in brake discs, tyres, and wheels. When it wears it can't do that so if you have discs which are perfectly OK and within tolerance you will feel them. Replace with "perfect" new ones and the problem goes away for a while. Same with the tyre and hunter balancing. Normally the car should be able to cope but if its tired then you get shimmy. Getting the wheels and tyres "perfect" on a hunter machine fixes it. It's not fixing the problem just masking it.
There are a lot of rubber bushes to change in the front of a E39 and then the shocks after that.
Just my opinion I am sure there are other causes.

[Harry]

If you haven’t done so already get the wheel balance checked. Been there done that. Warped disks are the next most likely cause. Good luck with it.

[E39mad]

I went through this about two years ago:

Started with balancing wheels and then alignment check, then went onto brakes and a disc was warped due to a sticking caliper!

If it was not brakes/caliper would have gone down suspension route of lower arm bushes, then arb links.

[Hearty]

I'd go for warped discs. Had this twice on mine.

Make sure you replace both discs and all pads - I used Bosch discs and pads that were designed to work with each other, and had no problems for 10k miles . . .

[boingboing]

Problem resolved

Had the discs and pads changed today and no more judder

Just hope it stays this way

[ice959]

some causes of brake disc warp:

harsh (late) braking all the time

sudden cooling when discs are warm ie car wash or driving through massive puddles - I always drive around big puddles!

also after you have done a long journey and your discs are at huge temps try not to squeeze on the brakes when waiting at give ways and round abouts as this causes immense heat build up at that point of the disc.

just my 2 pence!

oh and on my e39 my brake judder was due to my rear brake discs!

[v00d0019]

Judder from the back on my E46 touring was caused by a siezed caliper.

Stripping down, cleaning then bleeding brakes seems to have cured it.

Colleague here found the same thing with his E39 530d.

[recymech]

What did you use to clean and lubricate it with? Dont want to use anything detrimental to the brakes.