[danb1979]

^^^

Exactly what I've already said and linked to my previous F01 that everything was bang on, just passed the MOT with flying colours; but steering wheel would wobble at speed/brakes wobbled when slowing down etc

Turned out to be the thrust arm ball joints were shot; after 4months of being fitted (not by me)!

Only found out when I removed them!

[martin10chk]

Sorry but I am going to go back to something that has been said earlier because it aligns exactly with my experience (a long time ago now, but the same symptoms).

Issues with suspension wear are difficult to reconcile with the fact that the OP only gets the vibration problem after driving for some time (if I am reading it correctly). This seems to me to be a brake disc issue and when I suffered the same it came back to a sticking calliper.

OP - I know you say you have felt the wheels after a drive and they are the same temperature but this could be intermittent. What happened with mine was that a sticking calliper gave rise to the deposition on discs that others have talked about. And when the discs warm up you then get the judder.

I like you changed the discs and it seemed to sort the problem but came back. The new discs had suffered deposition on account of the sticking calliper. I sorted the problem by having callipers, discs and pads replaced.

So my diagnosis of your problem would be that: a defective calliper is causing brake pad deposition onto discs. Replace the discs and it happens all over again.

[JamesStam]

Originally Posted by danb1979

^^^

Exactly what I've already said and linked to my previous F01 that everything was bang on, just passed the MOT with flying colours; but steering wheel would wobble at speed/brakes wobbled when slowing down etc

Turned out to be the thrust arm ball joints were shot; after 4months of being fitted (not by me)!

Only found out when I removed them!

Thanks. I'm wondering whether to replace them with a Lemforder set to eliminate the possibility of the ball joint or bush.
Possibly will.

[JamesStam]

Originally Posted by martin10chk

Sorry but I am going to go back to something that has been said earlier because it aligns exactly with my experience (a long time ago now, but the same symptoms).

Issues with suspension wear are difficult to reconcile with the fact that the OP only gets the vibration problem after driving for some time (if I am reading it correctly). This seems to me to be a brake disc issue and when I suffered the same it came back to a sticking calliper.

OP - I know you say you have felt the wheels after a drive and they are the same temperature but this could be intermittent. What happened with mine was that a sticking calliper gave rise to the deposition on discs that others have talked about. And when the discs warm up you then get the judder.

I like you changed the discs and it seemed to sort the problem but came back. The new discs had suffered deposition on account of the sticking calliper. I sorted the problem by having callipers, discs and pads replaced.

So my diagnosis of your problem would be that: a defective calliper is causing brake pad deposition onto discs. Replace the discs and it happens all over again.

Very interesting.
The issue is definitely WORSE after driving for a while and heating up the brakes. It varies to be honest. Sometimes it's terrible, sometimes it's noticeable. How can I determine whether or not my caliper is functioning correctly?

[danb1979]

Originally Posted by JamesStam

Thanks. I'm wondering whether to replace them with a Lemforder set to eliminate the possibility of the ball joint or bush.
Possibly will.

Remove them and see what condition they're in. The bushes should have a tiny amount of movement, that's the correct compliance. Any more and they're shot.

The ball joint should move, but be stiff at the same time. If its loose/rattles etc, shot also...

I'm a big fan of Lemforder but it can take weeks from Autodoc.

Moog are one of my other go to's and you'll get that from your local motorfactors... Great warranty too on their parts

[Watsey]

Could be a sticking caliper ir pad. I had this happen once on my current car.

I won’t go into the technical details, because it was 100% caused by a unique aspect of my aftermarket brakes, but the inner pad of one of the front brakes was not fully releasing its pressure from the disc. It was only mild pressure but the continuous friction (especially at motorway speeds) caused the disc to badly overheat to the extent that the front of the car would shake violently as soon as the brake pedal was pressed.

If it’s not brakes, I’d look for signs of worn bushes in the tension struts and/or wishbones.

[TurboWeasel]

Seems there's a couple of things going on, wobbling and juddering. They are different sensations that lead you down different diagnostic paths.

Juddering is more fierce, like the drivetrain shaking from a juddering clutch.

A wobble is more akin to a lower frequency rocking.

The former can be caused by shot control arms shaking the steering wheel, shot ABS pump pulsing the brake pedal, or a knackered clutch if it's a manual.

Rocking can come from the ZF8 downshifting at slower speeds, which would be a lot more noticeable if the rear subframe bushes and/or diff mounts, trans mounts etc were shot.

Bushings and mounts heat up whilst driving, which can exacerbate any excessive movement issues.

Seems like the discs are fine. That run out is within tolerance.

[JamesStam]

Afternoon all,
I took the car to my local indy for a diagnosis.
I explained the issues. He listened.

I have just returned.

The long and short of it is - he's unsure what's causing the problem, but can feel the rocking/wobbling when braking.

The rolling road is showing both front and offside braking force pulsating (slightly) It is worse when hot.

The LEDs (representing the resistance force applied by braking) on the rolling road, when applying a constant brake pressure, were increasing then dipping on both offside wheels. 3 LEDs differentiationwhen warm, 1 or 2 when colder.

All suspension arms and bushes were checked for play. Nothing found. (I am aware that ball joint play is difficult to see unless the arm is disconnected ).

Totally perplexed. I suspect distorting discs when hot.

Driving me nuts.

[tango222]

I had what felt like warped discs, it was the brake reaction arms changed and it went away

[danb1979]

Originally Posted by JamesStam

Afternoon all,
I took the car to my local indy for a diagnosis.
I explained the issues. He listened.

I have just returned.

The long and short of it is - he's unsure what's causing the problem, but can feel the rocking/wobbling when braking.

The rolling road is showing both front and offside braking force pulsating (slightly) It is worse when hot.

The LEDs (representing the resistance force applied by braking) on the rolling road, when applying a constant brake pressure, were increasing then dipping on both offside wheels. 3 LEDs differentiationwhen warm, 1 or 2 when colder.

All suspension arms and bushes were checked for play. Nothing found. (I am aware that ball joint play is difficult to see unless the arm is disconnected ).

Totally perplexed. I suspect distorting discs when hot.

Driving me nuts.

Unless they're cheapy ECP jobbies, it's unlikely to be the discs

As already said, it's either the thrust arms or caliper issues..

Time to take things apart

[TurboWeasel]

Originally Posted by JamesStam

The rolling road is showing both front and offside braking force pulsating (slightly) It is worse when hot.

I take it you meant both front and rear offside?

Originally Posted by JamesStam

The LEDs (representing the resistance force applied by braking) on the rolling road, when applying a constant brake pressure, were increasing then dipping on both offside wheels. 3 LEDs differentiationwhen warm, 1 or 2 when colder.

I would disconnect the ABS/TC ECU, or pull a wheel speed sensor to disable it, and try the rolling road again.

Normally a brake master cylinder splits it's outputs diagonally to offside front to nearside rear, and near side front to offside rear in case of a circuit failure, but maybe BMW split it front and rear on the same side? I can't think of anything else that would affect only one side of the car when all discs are well within runout tolerance. Worth a go for the sake of a quick plug pull. You'll probably need a code reader to clear the resultant fault code though.

You could have a faulty tone ring on one of the offside hub knuckles which is causing the ABS pump to pulse the calipers gently.

As per an earlier post, have you checked the inboard faces of the discs for pad deposits?

[JamesStam]

Originally Posted by TurboWeasel

I take it you meant both front and rear offside?



I would disconnect the ABS/TC ECU, or pull a wheel speed sensor to disable it, and try the rolling road again.

Normally a brake master cylinder splits it's outputs diagonally to offside front to nearside rear, and near side front to offside rear in case of a circuit failure, but maybe BMW split it front and rear on the same side? I can't think of anything else that would affect only one side of the car when all discs are well within runout tolerance. Worth a go for the sake of a quick plug pull. You'll probably need a code reader to clear the resultant fault code though.

You could have a faulty tone ring on one of the offside hub knuckles which is causing the ABS pump to pulse the calipers gently.

As per an earlier post, have you checked the inboard faces of the discs for pad deposits?

Thanks for the reply. Yes I did mean front and rear, well spotted.
Unsure what to unplug as described above but will have a Google etc.
I did check the inside of the discs but only with a phone torch and the wheel off (not the disc). What exactly would I be looking for? Big dark pad marks or just slight imperfections?

My next step is to try and measure run out when the discs are hot/warm and see if that causes any significant run out increase.

Thereafter, I think I'll start replacing parts one by one.

[JamesStam]

Checked the run out with hot discs.
Exactly the same.

New discs next.

[danb1979]

Originally Posted by JamesStam

Checked the run out with hot discs.
Exactly the same.

New discs next.

Have you tried some hard but safe braking to see if it clears the pad deposits? What make are your discs and pads currently?

If you do buy new brakes, stick with ATE, OEM BMW or Jurid / Textar. Don't buy brakes from ECP

See what Douglas Park BMW on ebay can offer and try Cotswolds BMW too...

I'd fit new pads too. Makes a lot of sense to keep it all new and matched

[TurboWeasel]

Exactly the same as your previous measurements (0.02 - 0.04mm), or they are wildly off only when the discs are hot?

If it's the discs, as above, get genuine or a decent brand. I would check the hubs with the DTI for runout before fitting new discs. It's quite possible an ape over tightened the wheel bolts at some point, which can distort the hubs. If the hubs are distorted, the new discs will conform to that shape, meaning they will also warp!

[JamesStam]

Originally Posted by danb1979

Have you tried some hard but safe braking to see if it clears the pad deposits? What make are your discs and pads currently?

If you do buy new brakes, stick with ATE, OEM BMW or Jurid / Textar. Don't buy brakes from ECP

See what Douglas Park BMW on ebay can offer and try Cotswolds BMW too...

I'd fit new pads too. Makes a lot of sense to keep it all new and matched

Currently I have Pagid pads and Bosch discs on the front.

I did do some hard braking but it made no difference.

I have bought some Textar discs.

I wasn't planning on changing the pads for two reasons;
- Plenty of life left on them
- I want to rule in or out one component at a time.

Happy to be guided otherwise.

Thanks.

[JamesStam]

Originally Posted by TurboWeasel

Exactly the same as your previous measurements (0.02 - 0.04mm), or they are wildly off only when the discs are hot?

If it's the discs, as above, get genuine or a decent brand. I would check the hubs with the DTI for runout before fitting new discs. It's quite possible an ape over tightened the wheel bolts at some point, which can distort the hubs. If the hubs are distorted, the new discs will conform to that shape, meaning they will also warp!

Sorry, to be clear, the discs are the same run out measurements whether hot or cold (0.02mm - 0.04mm).

I will check the hubs prior to installation of the Textar Pro + discs I just bought on eBay.

Due in a couple days.

I have also bought some Lemforder control arms from Autodoc so will have them replaced after the discs.

Thanks for your continued advice etc.

[danb1979]

Originally Posted by JamesStam

Currently I have Pagid pads and Bosch discs on the front.

I did do some hard braking but it made no difference.

I have bought some Textar discs.

I wasn't planning on changing the pads for two reasons;
- Plenty of life left on them
- I want to rule in or out one component at a time.

Happy to be guided otherwise.

Thanks.

Replace the pads. They wear with the discs and you'll have to go through the bedding in procedures again anyway, so may as well start with all fresh items... And pads aren't expensive. Again, stick with the brands as above. Jurid are the OEM maker FYI.

Are you fitting it all or asking a garage to do it?

Either way, ensure that the hub face is absolutely spotless and NO grease is used whatsoever. This is often overlooked and cause cause further issues.

BMW states no grease / anti seize to be used at all bar a fine smear on the hubs outer lip, and that's it

[JamesStam]

Originally Posted by danb1979

Replace the pads. They wear with the discs and you'll have to go through the bedding in procedures again anyway, so may as well start with all fresh items... And pads aren't expensive. Again, stick with the brands as above. Jurid are the OEM maker FYI.

Are you fitting it all or asking a garage to do it?

Either way, ensure that the hub face is absolutely spotless and NO grease is used whatsoever. This is often overlooked and cause cause further issues.

BMW states no grease / anti seize to be used at all bar a fine smear on the hubs outer lip, and that's it

Ok, will do. Hopefully I can find some Jurid ones fairly quickly - I'm not paying £100+ for BMW pads.

I'll be changing the front discs. I note the guidance about the grease - what about back of the pads etc?

[Allworth]

Originally Posted by JamesStam

I note the guidance about the grease - what about back of the pads etc?

Yes, do grease.
Procedure from ISTA. Also, you may want a proper brake pad paste other than copper.

[danb1979]

Originally Posted by JamesStam

Ok, will do. Hopefully I can find some Jurid ones fairly quickly - I'm not paying £100+ for BMW pads.

I'll be changing the front discs. I note the guidance about the grease - what about back of the pads etc?

I use this and would highly recommend it

Liqui Moly 3418 Ceramic Paste 50 g https://amzn.eu/d/eQA32Rb

Stay away from copper grease. It had it's time..

[Mr.Smartepants]

Originally Posted by danb1979

Stay away from copper grease.

Why? It causes no harm and was recommended for years.
Are there better products? Yes. But there's nothing wrong with copper grease.