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Robobcop44

Will this stop the brake judder?

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Ok, so brake judder was getting to be a real pain! Cold brakes=no probs. hot brakes= judder. Very hot brakes = violent judder!

So, after consulting with an engineer, the conclusion is that it's the discs. They are the only things that can get so hot so quickly under braking....despite the fact that they've only done 2000 miles!

Here's what I did today, and it was a pain!

I stripped everything down, removing the calipers and discs. I have put new seals and pistons in the calipers, so I know that they are good. I also noticed that the bearings were a little poor. The passenger side felt firm enough, but made a clicking noise as it went round. You could feel this clicking as it turned. The drivers' side felt too easy to turn. No resistance at all and a slight rubbing noise, although no play in either, however, what would they be doing with all the weight of the front end, plus huge braking forces on them? So, I bought two new hubs. Despite only being held on with four bolts, they were a bugger to get off. Lots of heat was needed and I had to loosen the entire hub / suspension assembly and lower it from the shock to gain access to one awkward bolt. When will the fun ever end??

I now have new hubs / bearings, reconditioned calipers and new discs and pads. I will go easy for a while to let it all bed in and then see what happens. If I still get brake judder after all this work, I will roll the car off a cliff!

Just one other point, my issues were only under braking. At any speed there is not even the slightest vibration in the steering wheel and the handling and steering felt great, or as great as it gets with a numb steering box anyway! My wife's later shape Mondeo has much superior steering and precision!

Here endeth a long, hot, dirty, difficult, tiring Saturday underneath my lovely 540i. As much as I love the car, after all this work and toil, if it's not judder free now it can go sky diving, or fire eating, or on a demolition derby!

Just one other thing. How do I stop the bloody computer from telling me that my brake pads are worn?

They aren't and the sensors are new! Is it possible to disable this pain in the arse false message?

Thanks.

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 You'll need to reset the computer to get rid of the low brake pad warning, I can't remember how to do it off hand but google should tell you, I did it on mine ages ago. And hopefully, after all that work your judder is gone and it isn't knackered upper control arm bushes causing the problem......

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Thanks for that. I'll see if that works to get rid of the brake warning.

At first it would occasionally pop up while driving, but no while braking? It then just stayed on all of the time!

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Leaving the ignition on had no effect on the pad wear warning indicator. It may be time to short the sensor wires!

Do knackered upper control arm bushings really cause judder? I've heard they can, but how does a worn bush create vibration under braking yet not the whole time?

Thanks.

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I have slight vibration at high speeds nd lots of vibration under braking also not very responsive steering could this be my control arm bushes that are worn??

Thanks nd sorry to hi jack the post

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I have slight vibration at high speeds nd lots of vibration under braking also not very responsive steering could this be my control arm bushes that are worn??

Thanks nd sorry to hi jack the post

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I had various vibration and braking issues on my e39. I replaced the upper front control arms which are notorious for causing vibrations. The vibrations improved a bit but I then noticed the steering wheel shaking under gentle braking and the car pulling to the left under hard braking. I checked the brakes thinking it might be a sticky caliper or disc problems or worn dampers. It turned out to be the lower left control arm causing the problems. Now they are both changed all problems are gone. I went for lemforder arms from Mr auto. Cheapest place on the web. My thoughs are that on high mileage e39's its worth doing all 4 arms if you have strange vibrations or braking issues.

Edited by Sasitron

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I agree, Sasitron. I haven't yet hammered the brakes at speed but after all my work they feel very good so far now they are bedded in. If I have any more issues I'll change all four control arms.

So far, I have no vibration or shaking at ANY speed at all. From 10 to 150mph it's super smooth. I only had the issue under braking. I have braked hard a couple of times from around 80 and there's no vibration. I would have thought that if it was the control arms then it should do it at that. Before I only got vibration when the brakes got hot. I wouldn't have thought that control arms would behave the same, ie only cause vibration when the brakes are hot, and then not when they cool? Anyway, time will tell!

How on earth do I stop the computer telling me that my pads are worn?? I've so far found nothing of use on Google?

Thanks.

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Hi,

Switch the ignition to position 1 for 30 seconds I think....

Cheers,

Gavin:)

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Hi Gavin, that doesn't work, but seen your other message about a certain resistance needed so I will re-splice the sensor unit back into the circuit and see what happens.

Thanks.

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I haven't seen any documents that there should be any resistance on the sensor circuit. As long as the corresponding pin on the cluster is grounded the light should go out with the measure previously mentioned.

 

The sensor circuit is very simple in series:

 

Instrument cluster - front left - rear right - ground

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So how exactly do I cancel this brake warning message? The sensor cables are ok, as far as I know, one has a voltage, the other doesn't. Front and rear read the same. The sensor both show a closed circuit and are back in situ, but the message persists!

It's bugging the hell out of me!

Please help me! Thanks.

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Have you tried resetting the IKE? Test 21 in the hidden menu. If that doesn't work, I would suggest that there is a high resistance in your wiring. As Clavurion said, the wiring is a simple loop from Pin 4 on the Blue 26 pin connector on the back of the cluster, through both sensors in series and then back to Pin 20.

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Thanks for the link sharkfan, but that procedure has no effect at all. I will try the above suggested by RosieE39/2 next.

By the way, yesterday I was surprised at what doesn't cause brake judder! I discovered that one of my one week old hubs which I fitted last Saturday was buggered! I took the wheel off to investigate a bit a brake squeal and noticed that I could wobble the brake disc....quite a lot! When I removed the disc I found massive play in the new bearing! I had only done around 50 miles on it since fitting it! If I hadn't have noticed this, what could have happened in a thousand miles?? Potentially disastrous!

Despite the fact that my front wheel will have been wobbling very badly...no brake judder!trim.0E360462-8887-40A4-8A0E-2733643EDFB9.MOV

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I can't remember. Not a particularly cheap part. The one on the passenger side is fine.

I have just (this evening) replaced the defective hub and all seems well, so far!

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it would be good to know the brand of the bearing that failed after such a short time.  Where did you buy them?  I know there are quite a few Chinese fakes out there!

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Well, I took the car out for a long run today for the first time since doing all the brake / hub work..and rework! All is good.

Servicing the calipers has made a big difference to the feel of the brakes. I now need to apply less pedal force for harder, more responsive braking. There is also no hint of brake judder at any speed, even when I've got the discs hot. In fact, the brakes have never felt this good!

Based on what I've done, I believe that the calipers were in dire need of servicing (£40 for the kit from eBay) and the hubs were worn. Although they didn't feel too bad, who knows what they were doing with the massive forces put on them when braking?

I still can't get my pad warning message off though. A friend had a similar problem and needed a new dash!

At some stage I will remove the dash to sort my failing pixel issue, and will bypass the brake sensor circuit then. If that doesn't cure it, I'll live with it!

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I had various problems with brake shudder, until I replaced both the upper and lower control arms.  Although everything felt tight, and bushes seems ok, it was only when we took them off that the problem was revealed, it was actually the balljoint at the other end of the arm that had worn out, and had no resistance and was causing the noise and vibration.

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The control arms were replaced around 4 years ago, but they still could be worn I suppose. If I get any more issues in the future I will replace them. I didn't think that they were the issue this time as I only got judder when the discs got hot. Let then cool for a minute and the judder would disappear......until they got hot again. I do think that the semi seized calipers and knackered bearings had played a big part in destroying my discs.

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