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M40i brakes - design flaw uncovered

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Wyldie85
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M40i brakes - design flaw uncovered

Post by Wyldie85 » Wed May 27, 2020 12:14 pm

Number5 wrote: Fri Mar 06, 2020 7:40 pm We’ve only had our G29. 30i six days and this happened today on a short 1 mile trip from home to Tesco on standard residential roads. It has the M Sport + brake package too.
The stone was in the front near side wheel. My wife drove it into the dealers, Dick Lovett, Bristol (where I work) and they popped it on the ramp, took the wheel off and removed the stone.

I wasn’t on site at the time but I’ll try and follow this up with the Workshop Manager next week and see how common it is.

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Perks of the job huh! My next available appointment at my local dealer to sort the annoying I drive bugs and rubbish speakers is the 17th of June and a £15.00 charge for decontamination.

Still no issues with stones on mine but the brakes squeak a lot now. Attracts attention in town for all the wrong reasons. :|
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M40i brakes - design flaw uncovered

Post by Blue29 » Sun Aug 02, 2020 10:57 pm

Had this once in 5000 miles. It made a hell of a screech and I did wonder what the hell had happened at first. Once I stopped and reversed a few feet, it came loose and fell out. No problem since
Exactly this happened to me today. Luckily I was pulling out of a country car park so easy to stop and reverse - hopefully it never happens on a motorway.
Is it worth reporting to BMW?

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M40i brakes - design flaw uncovered

Post by ronk » Sun Aug 02, 2020 11:18 pm

I remember seeing big sporty type motor bikes in my youth - the big Norton’s and Triumphs etc - they had big drum brakes on the front and had an air scoop - this always had a open mesh cover.

Im sure it’s not beyond the wit of man to fabricate something to cover the void this flare on the backplate?

The M40i that I took out on test had a stone wedge before 30 miles were done. The more folk who complain the better in my opinion.
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M40i brakes - design flaw uncovered

Post by Jim S » Mon Aug 03, 2020 3:49 pm

Blue29 wrote: Sun Aug 02, 2020 10:57 pm
Had this once in 5000 miles. It made a hell of a screech and I did wonder what the hell had happened at first. Once I stopped and reversed a few feet, it came loose and fell out. No problem since
Exactly this happened to me today. Luckily I was pulling out of a country car park so easy to stop and reverse - hopefully it never happens on a motorway.
Is it worth reporting to BMW?
Sounds horrible. Glad you managed to get the stone to come out. It has happened to me 5 times now. Reported to my dealer each time but I found out that nothing gets reported back to BMW unless the car is booked in to the dealer for inspection. :headbang:

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M40i brakes - design flaw uncovered

Post by Blue29 » Mon Aug 17, 2020 7:33 pm

This time the stone didn't come out. After 5mins one stone came out (lots of reversing) and after another 5mins another stone came out when making a right turn.

Videos attached of the horrible noise.

Edit: videos didn't upload so here's a couple YouTube links.

2 stones - noise going forwards and reverse
https://youtu.be/GYs6w_2ohUs

1 stone - noise going forwards only
https://youtu.be/YdWhXNaX7jQ

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M40i brakes - design flaw uncovered

Post by raven » Fri Aug 21, 2020 5:35 pm

Blue29 wrote: Mon Aug 17, 2020 7:33 pm This time the stone didn't come out. After 5mins one stone came out (lots of reversing) and after another 5mins another stone came out when making a right turn.

Videos attached of the horrible noise.

Edit: videos didn't upload so here's a couple YouTube links.

2 stones - noise going forwards and reverse
https://youtu.be/GYs6w_2ohUs

1 stone - noise going forwards only
https://youtu.be/YdWhXNaX7jQ
that sound , gave me the chills, sounds horrible, thats when driving without applying the brakes?
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M40i brakes - design flaw uncovered

Post by Blue29 » Fri Aug 21, 2020 9:31 pm

raven wrote: Fri Aug 21, 2020 5:35 pm that sound , gave me the chills, sounds horrible, thats when driving without applying the brakes?
No braking to cause the noise - it was completely unavoidable.

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M40i brakes - design flaw uncovered

Post by Flyingfifer » Sat Sep 05, 2020 7:42 pm

Blue29 wrote: Mon Aug 17, 2020 7:33 pm 2 stones - noise going forwards and reverse
https://youtu.be/GYs6w_2ohUs

1 stone - noise going forwards only
https://youtu.be/YdWhXNaX7jQ
Thats HORRENDOUS :thumbsdown: :fuelfire:

Id be going mental if id shelled out all that cash for the motor and it was doing that, wonder if the Supra has the same issue? If not might be worth buying the Toyota guard, surely a straight swap!
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M40i brakes - design flaw uncovered

Post by Dukeman » Sun Sep 27, 2020 1:41 pm

Not had that problem with ours but brakes do feel spongy. In for first service soon so I will mention that.

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M40i brakes - design flaw uncovered

Post by ronk » Sun Sep 27, 2020 2:02 pm

Dukeman wrote: Sun Sep 27, 2020 1:41 pm Not had that problem with ours but brakes do feel spongy. In for first service soon so I will mention that.
I wouldn’t be waiting for the service to cure the spongey brakes.
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M40i brakes - design flaw uncovered

Post by john-e89 » Mon Sep 28, 2020 8:59 pm

ronk wrote: Sun Sep 27, 2020 2:02 pm
Dukeman wrote: Sun Sep 27, 2020 1:41 pm Not had that problem with ours but brakes do feel spongy. In for first service soon so I will mention that.
I wouldn’t be waiting for the service to cure the spongey brakes.
Tbh spongy brakes were something I found on a recent 6 day test on an M40i, they’re certainly not as hard as an M for example but just imo a trait of the brake caliper design. I’d wager you’ll get nowhere mentioning it as the car is so new and you’re not losing fluid. Accept it for what it is perhaps, they do work very well no...?
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M40i brakes - design flaw uncovered

Post by ronk » Mon Sep 28, 2020 9:29 pm

I have to admit that I didn’t notice any difference between my 35is and the M40i that they gave me on test - apart from the trapped stone during the test drive of course!
You don't stop playing when you get old - You get old when you stop playing!
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M40i brakes - design flaw uncovered

Post by John H100 » Tue Sep 29, 2020 12:53 pm

Screenshot 2020-09-29 at 16.43.18.png
Screenshot 2020-09-29 at 16.43.18.png (259.2 KiB) Viewed 2000 times
Just had the issue with the Mrs 2019 Mini Cooper S.....it appears to be a design issue across the BMW range.....the shield does not extend over the disc.

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M40i brakes - design flaw uncovered

Post by Swiftly » Tue Nov 17, 2020 10:08 pm

I suppose it was only a matter of time before I fell victim too. After 14 months of ownership and 6K miles, I managed to get a stone lodged in the front near side wheel just as I arrived home last night. What a horrendous noise it made, and despite reversing and braking, I wasn't able to dislodge the stone. This morning I placed a call with BMW Assist, and when the chap arrived he took the wheel off and removed a small wedge shaped stone which had managed to jam itself good and proper. The chap also mentioned that it is now becoming a common issue The brake disc was checked, and luckily no damage was done, so all good thankfully.
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20201117_103029.jpg (146.5 KiB) Viewed 1715 times
The offending stone with a 5 pence coin for size comparison.
20201117_104032.jpg
20201117_104032.jpg (34.07 KiB) Viewed 1715 times
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M40i brakes - design flaw uncovered

Post by ronk » Tue Nov 17, 2020 10:14 pm

I hope they (BMW) will listen - If their assist agents are noticing the problem there must be documentation going back I would hope?
You don't stop playing when you get old - You get old when you stop playing!
So I bought a 35is with all the toys to play with. :thumbsup:

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