Braking rattle?

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blue
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Braking rattle?

Post by blue »

Hi MG SV EV owners!

I took one for a test drive today and was pretty happy with it. Whilst I could talk about the good things I would like to ask about something that I found offputting.

A lot of the time when in cruise control when the car transitioned from driving to braking (when the car ahead slowed down at the lights for example) a quite noticable rattle occurred. It was similar to what I have experienced in other cars when first driving off which I think is the ABS self test. I also heard it occasionally when driving without cruise cotnrol and I applied the brake.

Is this normal?
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coulomb
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Re: Braking rattle?

Post by coulomb »

blue wrote: Fri, 27 Aug 2021, 13:37 A lot of the time when in cruise control when the car transitioned from driving to braking (when the car ahead slowed down at the lights for example) a quite noticeable rattle occurred.
Is this a fairly sharp, loud, but very short duration thing? I've been noticing that on mine occasionally. It feels as though the system decided to slam on the brakes, then 10 ms later changed its mind and released them. Because it's of such very short duration, it doesn't seem to affect driving at all.

As to whether this is "normal", I don't know.

The MG ZS EV MG Pilot system seems to be essentially a Bosch system that is also provided on many other models of other brands, e.g. VW Golfs, and possibly later Nissan Leafs.
MG ZS EV 2021 April 2021. Nissan Leaf 2012 with new battery May 2019.
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blue
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Re: Braking rattle?

Post by blue »

coulomb wrote: Fri, 27 Aug 2021, 15:11 Is this a fairly sharp, loud, but very short duration thing?
Yes I would say that was my experience. I agree it didn't change the driving feel but I found it quite loud. Will be interesting to hear from others about whether this is a fault? Do you find it with cruise on, off or both?
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Re: Braking rattle?

Post by blue »

Actually might be this I guess? https://mgmotor.com.au/mg-family/news-a ... %20ZS%20EV.

edit: read a few articles and Im not 100% sure...?
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coulomb
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Re: Braking rattle?

Post by coulomb »

blue wrote: Fri, 27 Aug 2021, 15:14Do you find it with cruise on, off or both?
I'm pretty sure it's to do with the frontal collision detection feature, which can happen with cruise control on or off. My vague recollection is of mostly with cruise control on, however.
MG ZS EV 2021 April 2021. Nissan Leaf 2012 with new battery May 2019.
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Patching PIP-4048/5048 inverter-chargers.
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Re: Braking rattle?

Post by Nagaman »

I’m a left foot braker and both the Model 3 and ZSEV start chattering if I’m manoeuvring back and forth parking etc.
The stop lights active at the same time the accelerator pedal is touched causes the ABS solenoid/pump whatever to machine gun rattle and the odd warning bong.
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Re: Braking rattle?

Post by kesselrig »

Hi Blue, I think I've experienced this a few times.

Each time it has come as a surprise and it's so brief that its gone by the time I realise its happening. When I was trying to assess what it was like, it sounded like something plastic got caught under the vehicle and was dragged for an instant or that something had gone wrong when the motor switched to regenerative breaking. Certainly a very brief sharp sound when transitioning from the "gas" to brake pedal.

It's somewhat reassuring to hear that others have experienced something similar which indicates either that this is normal (e.g. brake vacuum pump) or if it were an issue, it's widespread enough that it will be diagnosed and resolved.
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Re: Braking rattle?

Post by FyKnight »

I turn off the forward collision detection every time I start the car because this happens annoyingly often on mine and gives me a big shock. It's exactly as you describe: the emergency brake freaking out for one cycle then aborting the next. It's more likely to happen on curves, dips and black cars. I also thought it was something caught under the car when I first noticed it! I asked the MG service centre about it when I took it for the 1000 km service and they said "you know it's an EV, it has a lot of actuators"... :| ... really? It's not some sort of robot, in fact it's gotta have less actuators than the petrol version! Anyway no error codes had been logged so they said it was normal.

It took me a long process of trial and error to figure out that it was the forward collision detection that causes it. This is the one thing I'd like to have an app to do for me, turn this feature off on every startup since the side effects are too bad.
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