Brake pulsing/disc warping
Discussion
(Short version)
What could cause front discs to keep warping or wearing unevenly every time they are replaced?
(Long version)
I have a 2017 F30 320d with a problem that my garage cannot get to the bottom of.
The problem first occurred about 2 years ago, when the car had done around 35,000 miles. It started with a gentle pulsing as I braked. The frequency of the pulsing was wheel speed related and you could feel it in the peddle and also in your bum as the retardation increased, and then decreased with every turn of the wheels.
This got worse and worse over the passing miles and became really intrusive. The car was shortly due a service so I put up with it for a while, as it continued to get worse.
When it went in for a routine service I asked them to take a look at it and, sure enough, they said the front discs were warped and needed to be replaced. This completely solved the problem.
3000 miles later and I sensed the problem was returning. Sure enough, as the miles passed it got worse and worse all over again. It went into the garage and I explained the symptoms, that it had done exactly the same thing before and that there must be something else wrong that is causing the discs to warp, maybe wheel bearings, for example. They could not find any underlying issues and just changed the front discs and pads again. The car was fine again.
3000 miles later, you guessed it. The same thing all over again. Back into the garage for another inspection and another set of front discs and pads. This time they noticed a slightly buckled front wheel, which was straightened. Away I went, car feeling normal again.
3000 miles on brings us up to date and the brakes are starting to pulse again.
Does anybody have any ideas what could be constantly causing the discs to warp or wear unevenly? The car is not driven hard so the brakes never get particularly hot.
What could cause front discs to keep warping or wearing unevenly every time they are replaced?
(Long version)
I have a 2017 F30 320d with a problem that my garage cannot get to the bottom of.
The problem first occurred about 2 years ago, when the car had done around 35,000 miles. It started with a gentle pulsing as I braked. The frequency of the pulsing was wheel speed related and you could feel it in the peddle and also in your bum as the retardation increased, and then decreased with every turn of the wheels.
This got worse and worse over the passing miles and became really intrusive. The car was shortly due a service so I put up with it for a while, as it continued to get worse.
When it went in for a routine service I asked them to take a look at it and, sure enough, they said the front discs were warped and needed to be replaced. This completely solved the problem.
3000 miles later and I sensed the problem was returning. Sure enough, as the miles passed it got worse and worse all over again. It went into the garage and I explained the symptoms, that it had done exactly the same thing before and that there must be something else wrong that is causing the discs to warp, maybe wheel bearings, for example. They could not find any underlying issues and just changed the front discs and pads again. The car was fine again.
3000 miles later, you guessed it. The same thing all over again. Back into the garage for another inspection and another set of front discs and pads. This time they noticed a slightly buckled front wheel, which was straightened. Away I went, car feeling normal again.
3000 miles on brings us up to date and the brakes are starting to pulse again.
Does anybody have any ideas what could be constantly causing the discs to warp or wear unevenly? The car is not driven hard so the brakes never get particularly hot.
Most often it's due to brake pads - uneven brake pad deposits on the discs. Get a harder compound. BTW, what discs and pads do you have - brand and exact type/model?
I would not suspect sticky callipers at such a new car; if any of them s sticking the affected wheel should be significantly hotter than the others.
I would not suspect sticky callipers at such a new car; if any of them s sticking the affected wheel should be significantly hotter than the others.
Edited by naturalaspiration on Sunday 6th February 21:52
Edited by naturalaspiration on Sunday 6th February 21:57
It‘s complicated.
Your suspension is a system. Every system has a natural frequency. If you excite it at this frequency it will vibrate, a lot.
Some suspension has a natural frequency that is close to a brake induced excitation frequency. It’s not that there is anything really wrong, or broken.
So, try one or a combination of these…change your discs, clean the mating surfaces completely between hub and brake, or better still fit new hubs. Try a more aggressive brake pad, maybe sintered metal. Fit new/uprated suspension bushes from an M3. Swop your tyres Front to rear.
Your suspension is a system. Every system has a natural frequency. If you excite it at this frequency it will vibrate, a lot.
Some suspension has a natural frequency that is close to a brake induced excitation frequency. It’s not that there is anything really wrong, or broken.
So, try one or a combination of these…change your discs, clean the mating surfaces completely between hub and brake, or better still fit new hubs. Try a more aggressive brake pad, maybe sintered metal. Fit new/uprated suspension bushes from an M3. Swop your tyres Front to rear.
I had this on my 530i touring after replacing the discs and pads...it did my head in and I ended up replacing lots of bits including the wheels (which were both buckled)
Mutilple garages said the same thing "discs are warped mate" I always questioned this though as steel that thick doesn't just bend out of shape.
Anyway, after replacing various suspension bits and the wheels it got a better and eventually disappeared completely.
I'm glad I didn't just replace the discs as it seemed daft to me that virtually brand new discs would suddenly warp. My feeling is that it was something to do with the brake pad deposits coupled with knackered wheels and trackrods.
Mutilple garages said the same thing "discs are warped mate" I always questioned this though as steel that thick doesn't just bend out of shape.
Anyway, after replacing various suspension bits and the wheels it got a better and eventually disappeared completely.
I'm glad I didn't just replace the discs as it seemed daft to me that virtually brand new discs would suddenly warp. My feeling is that it was something to do with the brake pad deposits coupled with knackered wheels and trackrods.
Disks don't warp from road driving they really don't any garage that says they do are liars same for changing pads utter BS but was does wear out is your suspension when you brake you put stress through it and it shows up as brake judder, as for fitting M3 bushes well that's hilarious if they are worn just fit the ones BMW designed for your car not another model.
Wills2 said:
Disks don't warp from road driving they really don't any garage that says they do are liars same for changing pads utter BS but was does wear out is your suspension when you brake you put stress through it and it shows up as brake judder, as for fitting M3 bushes well that's hilarious if they are worn just fit the ones BMW designed for your car not another model.
It’s not hilarious. It’s an attempt to gain modal separation. It’s how cars are tuned. I’m just heading into work to do exactly that. The car is being measured on a rig to see if it works. Weird, no one is laughing!See 3.3
https://citeseerx.ist.psu.edu/viewdoc/download?doi...
Edited by Kawasicki on Monday 7th February 05:30
Thanks everybody for the quick replies, it is much appreciated.
Next question, to test naturalaspiration's theory, is there a way of cleaning the pad deposits off the discs to see if the problem goes away for a while?
naturalaspiration said:
Most often it's due to brake pads - uneven brake pad deposits on the discs. Get a harder compound. BTW, what discs and pads do you have - brand and exact type/model?
I would not suspect sticky callipers at such a new car; if any of them s sticking the affected wheel should be significantly hotter than the others.
This has the ring of truth about it. I need to call the garage to check, but I think the problem started accuring after the front pads were changed for the first time.I would not suspect sticky callipers at such a new car; if any of them s sticking the affected wheel should be significantly hotter than the others.
Lincsls1 said:
Have you had the calipers thoroughly inspected for smooth and correct operation?
A sticking piston for example could cause this problem.
No, I haven't but the pads are not wearing out particularly quickly and I'm getting over 50 mpg so I think this is unlikely.A sticking piston for example could cause this problem.
Higgs boson said:
This.
Although, 3000 mile intervals is weird.
Is there a chance that the car sits for a while, unused, after such a duration?
No, the car never sits for more than a day without being used. I am thinking that the problem is being caused by uneven deposits of pad material on the discs and that it takes 3000 miles for this to get to a noticeable level. From there on it just gets progressively worse.Although, 3000 mile intervals is weird.
Is there a chance that the car sits for a while, unused, after such a duration?
Kawasicki said:
It‘s complicated.
Your suspension is a system. Every system has a natural frequency. If you excite it at this frequency it will vibrate, a lot.
Some suspension has a natural frequency that is close to a brake induced excitation frequency. It’s not that there is anything really wrong, or broken.
So, try one or a combination of these…change your discs, clean the mating surfaces completely between hub and brake, or better still fit new hubs. Try a more aggressive brake pad, maybe sintered metal. Fit new/uprated suspension bushes from an M3. Swop your tyres Front to rear.
The suspension has been checked and no problems have been found. The rate at which the problem occurs is not getting quicker so I don't think it is related to bushes deteriorating, and I would be very surprised if that was the problem as it first became noticeable when the car was only 2 years old.Your suspension is a system. Every system has a natural frequency. If you excite it at this frequency it will vibrate, a lot.
Some suspension has a natural frequency that is close to a brake induced excitation frequency. It’s not that there is anything really wrong, or broken.
So, try one or a combination of these…change your discs, clean the mating surfaces completely between hub and brake, or better still fit new hubs. Try a more aggressive brake pad, maybe sintered metal. Fit new/uprated suspension bushes from an M3. Swop your tyres Front to rear.
Next question, to test naturalaspiration's theory, is there a way of cleaning the pad deposits off the discs to see if the problem goes away for a while?
Some hard & firm braking, from speed, when safe to do so will clear pad deposits. Drive around normally after to let the brakes cool…
But this may not cure it; as others have said, it can be bad callipers (seized components), failed/failing bushes, inner tie rods & track rod ends failing/seized, failing top mounts, ill fitted suspension (ie shock/spring not mounted correctly - although this may be more related to older BMWs)
Can also be tyre & alloy issues…
Brakes don’t warp unless they’re crap from factory
Thoroughly cleaned mounting surfaces is paramount also; and adding no grease is key for me also. I never do this now and have had no issues, at all. A lot of the more modern cars require this as per the TIS manuals etc
I personally use ATE discs and their ceramic pads now; never had any issues with these and as the pads are a bit more aggressive (and great for very little brake dust) they keep the disc faces clean really well. I’ve got them ordered for my F01 via Autodoc
Textar, Jurid, TRW and ATE are OEM FYI. The ceramic pads aren’t OEM, but they’re a worthy upgrade IMO
Brembo discs are good, I’ve always found their pads to be crap though
But this may not cure it; as others have said, it can be bad callipers (seized components), failed/failing bushes, inner tie rods & track rod ends failing/seized, failing top mounts, ill fitted suspension (ie shock/spring not mounted correctly - although this may be more related to older BMWs)
Can also be tyre & alloy issues…
Brakes don’t warp unless they’re crap from factory
Thoroughly cleaned mounting surfaces is paramount also; and adding no grease is key for me also. I never do this now and have had no issues, at all. A lot of the more modern cars require this as per the TIS manuals etc
I personally use ATE discs and their ceramic pads now; never had any issues with these and as the pads are a bit more aggressive (and great for very little brake dust) they keep the disc faces clean really well. I’ve got them ordered for my F01 via Autodoc
Textar, Jurid, TRW and ATE are OEM FYI. The ceramic pads aren’t OEM, but they’re a worthy upgrade IMO
Brembo discs are good, I’ve always found their pads to be crap though
Edited by d_a_n1979 on Monday 7th February 13:11
Edited by d_a_n1979 on Monday 7th February 13:12
Just adding someone else's experience for reference:
https://www.6post.com/forums/showthread.php?t=1698...
https://www.6post.com/forums/showthread.php?t=1698...
Sounds like the exact same problem I had with my girlfriends Renault Twingo. When we test drove the car the brakes were 'pulsing'. The dealer agreed to replace the discs and pads before we picked the car up, which they did. A few thousand miles later they started pulsing again. I put it down to the dealer doing something wrong so I ordered new discs and pads again and fitted them myself. Again after a few thousand miles the same pulsing came back. I stripped everything down and cleaned all the mating surfaces. Discovered some damage to the hub face so filed it down flat, mounted the discs and checked the runout. The passenger side only had around 0.003" runout, which is fine, but the drivers side was around 0.013" runout! Removed the disc and checked the hub and even the hub was running out. Came to the conclusion that the car must have had a bump of some sort as even one of the alloys was slightly different to the other 3! I ended up having a local garage skim the disc while on the car and the problem never returned. Cost £20 to get it done. We never kept it long afterwards but obviously if someone replaced the discs again then the problem would reappear.
I suppose while the disc is new it feels fine and smooth. After a while the disc wears unevenly and the thickness varies, resulting in the pulsing feeling.
If you can I would check the disc runout and work back from there to find the cause of the runout.
I suppose while the disc is new it feels fine and smooth. After a while the disc wears unevenly and the thickness varies, resulting in the pulsing feeling.
If you can I would check the disc runout and work back from there to find the cause of the runout.
Matt W said:
(Short version)
What could cause front discs to keep warping or wearing unevenly every time they are replaced?
(Long version)
I have a 2017 F30 320d with a problem that my garage cannot get to the bottom of.
The problem first occurred about 2 years ago, when the car had done around 35,000 miles. It started with a gentle pulsing as I braked. The frequency of the pulsing was wheel speed related and you could feel it in the peddle and also in your bum as the retardation increased, and then decreased with every turn of the wheels.
This got worse and worse over the passing miles and became really intrusive. The car was shortly due a service so I put up with it for a while, as it continued to get worse.
When it went in for a routine service I asked them to take a look at it and, sure enough, they said the front discs were warped and needed to be replaced. This completely solved the problem.
3000 miles later and I sensed the problem was returning. Sure enough, as the miles passed it got worse and worse all over again. It went into the garage and I explained the symptoms, that it had done exactly the same thing before and that there must be something else wrong that is causing the discs to warp, maybe wheel bearings, for example. They could not find any underlying issues and just changed the front discs and pads again. The car was fine again.
3000 miles later, you guessed it. The same thing all over again. Back into the garage for another inspection and another set of front discs and pads. This time they noticed a slightly buckled front wheel, which was straightened. Away I went, car feeling normal again.
3000 miles on brings us up to date and the brakes are starting to pulse again.
Does anybody have any ideas what could be constantly causing the discs to warp or wear unevenly? The car is not driven hard so the brakes never get particularly hot.
One thing that has cropped up on the BMW 5 forums is a damaged hub/bearing:What could cause front discs to keep warping or wearing unevenly every time they are replaced?
(Long version)
I have a 2017 F30 320d with a problem that my garage cannot get to the bottom of.
The problem first occurred about 2 years ago, when the car had done around 35,000 miles. It started with a gentle pulsing as I braked. The frequency of the pulsing was wheel speed related and you could feel it in the peddle and also in your bum as the retardation increased, and then decreased with every turn of the wheels.
This got worse and worse over the passing miles and became really intrusive. The car was shortly due a service so I put up with it for a while, as it continued to get worse.
When it went in for a routine service I asked them to take a look at it and, sure enough, they said the front discs were warped and needed to be replaced. This completely solved the problem.
3000 miles later and I sensed the problem was returning. Sure enough, as the miles passed it got worse and worse all over again. It went into the garage and I explained the symptoms, that it had done exactly the same thing before and that there must be something else wrong that is causing the discs to warp, maybe wheel bearings, for example. They could not find any underlying issues and just changed the front discs and pads again. The car was fine again.
3000 miles later, you guessed it. The same thing all over again. Back into the garage for another inspection and another set of front discs and pads. This time they noticed a slightly buckled front wheel, which was straightened. Away I went, car feeling normal again.
3000 miles on brings us up to date and the brakes are starting to pulse again.
Does anybody have any ideas what could be constantly causing the discs to warp or wear unevenly? The car is not driven hard so the brakes never get particularly hot.
https://forum.bmw5.co.uk/topic/147565-7-millionth-...
Could be worth looking into as a well as all the above
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