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Discussion Starter #1
Have posted this on "MGEVs Community" and thought I'd duplicate the discussion here in case anyone here is not on MGEVs community and can shed some light on this weird grinding/scrunching noise? I suspect if you always travel with the radio on you may not be aware of it. Some of the replies I've had suggest it is the "brake vacuum assistance pump" but the noise is more of a metal on metal grind - any ideas would be most welcome.

Thanks



"Hi all - wondering if anyone else has experienced this?

In the early days the noise was like that when a brake drum has worn down and you get a loud metal on metal sound - only lasts a second and is intermittent - only seems to happen at low speed (under 17mph) - sometimes when slowly accelerating, sometimes just cruising, sometimes easing off and regen starts to kick in.

Noise has progressed to a quieter scrunch - same symptoms and sometimes the car's speed is clearly momentarily slowed down. Seems to emanate from front right side.

Reported it just before lockdown but only able to get it back to dealer last week - lubricated suspension (?) and returned car.

It happened again today so back the car has gone....

Anyone else had similar issues? "
 

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Have posted this on "MGEVs Community" and thought I'd duplicate the discussion here in case anyone here is not on MGEVs community and can shed some light on this weird grinding/scrunching noise? I suspect if you always travel with the radio on you may not be aware of it. Some of the replies I've had suggest it is the "brake vacuum assistance pump" but the noise is more of a metal on metal grind - any ideas would be most welcome.

Thanks



"Hi all - wondering if anyone else has experienced this?

In the early days the noise was like that when a brake drum has worn down and you get a loud metal on metal sound - only lasts a second and is intermittent - only seems to happen at low speed (under 17mph) - sometimes when slowly accelerating, sometimes just cruising, sometimes easing off and regen starts to kick in.

Noise has progressed to a quieter scrunch - same symptoms and sometimes the car's speed is clearly momentarily slowed down. Seems to emanate from front right side.

Reported it just before lockdown but only able to get it back to dealer last week - lubricated suspension (?) and returned car.

It happened again today so back the car has gone....

Anyone else had similar issues? "
Is it like a quick / short "Rasping / Thraping" sound that appears to come from behind the drivers steering wheel, that only lasts a few seconds.
It tends to be more noticeable at lower speeds and is a little random of when it happens ?.
If so, then I think what you are hearing is the brake booster charging.
It does sometimes sound like a grating noise.
Other owners have also reported this strange ( but pretty normal to the ZS EV ) phenomenon.
It took me a while before I actually encountered it !.
 

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Discussion Starter #3
Is it like a quick / short "Rasping / Thraping" sound that appears to come from behind the drivers steering wheel, that only lasts a few seconds.
It tends to be more noticeable at lower speeds and is a little random of when it happens ?.
If so, then I think what you are hearing is the brake booster charging.
It does sometimes sound like a grating noise.
Other owners have also reported this strange ( but pretty normal to the ZS EV ) phenomenon.
It took me a while before I actually encountered it !.
[/QUO


Yes, only at low speeds (under 20mph) - lasts a few seconds - think from front right side - very intermittent - grating/rasping/scrunch. Can this be "normal"? Does it happen on other EVs or specific to MG ZS? It is really disconcerting and not what I would expect from a brand new car of any powertrain.
 

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Have posted this on "MGEVs Community" and thought I'd duplicate the discussion here in case anyone here is not on MGEVs community and can shed some light on this weird grinding/scrunching noise? I suspect if you always travel with the radio on you may not be aware of it. Some of the replies I've had suggest it is the "brake vacuum assistance pump" but the noise is more of a metal on metal grind - any ideas would be most welcome.

Thanks



"Hi all - wondering if anyone else has experienced this?

In the early days the noise was like that when a brake drum has worn down and you get a loud metal on metal sound - only lasts a second and is intermittent - only seems to happen at low speed (under 17mph) - sometimes when slowly accelerating, sometimes just cruising, sometimes easing off and regen starts to kick in.

Noise has progressed to a quieter scrunch - same symptoms and sometimes the car's speed is clearly momentarily slowed down. Seems to emanate from front right side.

Reported it just before lockdown but only able to get it back to dealer last week - lubricated suspension (?) and returned car.

It happened again today so back the car has gone....

Anyone else had similar issues? "
Taken from MG Owners Club,
Q What is the intermittent grinding sound that I can sometimes hear from somewhere in the car.
A It is the ABS (anti-lock brake system) and AEB (automatic emergency brake) priming itself to stop in case you don’t! Generally the car's cameras have seen something it thinks might be a risk.
 

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I've occasionally had this, and usually it's immediately followed by an alert about a potential collision.
 

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Discussion Starter #6
I've occasionally had this, and usually it's immediately followed by an alert about a potential collisio
Taken from MG Owners Club,
Q What is the intermittent grinding sound that I can sometimes hear from somewhere in the car.
A It is the ABS (anti-lock brake system) and AEB (automatic emergency brake) priming itself to stop in case you don’t! Generally the car's cameras have seen something it thinks might be a risk.
I hope this is the case but I never thought my driving was so bad that it would happen 4 times in an 11 mile trip! It is a very disconcerting grinding/scrunch and if it happened on a test drive there is no way the car would be bought.

It has also happened on a straight road at about 17 mph with nothing in front of me - but there were cars coming the other way on the opposite carrigeway - mmm???? Most of my driving is city based so there are a lot of possible obstructions. If it is AEB/ABS priming triggered by the cameras perhaps they are over sensitive. Car now back at dealer so I'll report his findings when he's finished.

Thanks for your comments.
 

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Discussion Starter #7
I've occasionally had this, and usually it's immediately followed by an alert about a potential collision.
Thanks Paul - my grinding noise hasn't been associated with collision alert coming on - although that has happened a couple of times on other occasions. Let's see what the dealer can find - fingers crossed.
 

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Discussion Starter #8

This is such a disconcerting grinding noise, often associated with loss of power momentarily, that if it happened on a test drive there is no way I would buy that car - that surely must be an indicator that it cannot be "normal". ?
 

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Loss of power and the above comment about ABS priming, hmm. This is going to be very anecdotal, but the 3 series BMW I'm swappaging for a ZS recently had to have its abs sensors replaced, this is to do with a well known issue with the reluctor ring that helps judge wheel speed swelling due to corrosion and touching the sensor on a wheel so the ABS primes and reduces speed (not fun on a motorway, pretty much won't accelerate above 40mph). It could be that with the ZS when the abs primes it is detecting a change in wheel speed / slippage on a wheel? Does it happen when cornering, coming off a roundabout or tackling uneven surfaces?(these were all the queues for the Beemer to kick in the ABS and then throw the error continuously, which I relasie you don't have, but my speculation is that it could be a detected loss of wheel speed, is priming the abs (the crunch) and then limiting power, but correcting itself and not kicking in).
 
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Discussion Starter #10
Loss of power and the above comment about ABS priming, hmm. This is going to be very anecdotal, but the 3 series BMW I'm swappaging for a ZS recently had to have its abs sensors replaced, this is to do with a well known issue with the reluctor ring that helps judge wheel speed swelling due to corrosion and touching the sensor on a wheel so the ABS primes and reduces speed (not fun on a motorway, pretty much won't accelerate above 40mph). It could be that with the ZS when the abs primes it is detecting a change in wheel speed / slippage on a wheel? Does it happen when cornering, coming off a roundabout or tackling uneven surfaces?(these were all the queues for the Beemer to kick in the ABS and then throw the error continuously, which I relasie you don't have, but my speculation is that it could be a detected loss of wheel speed, is priming the abs (the crunch) and then limiting power, but correcting itself and not kicking in).
mmm ... interesting analogy. It has happened when taking off from lights and turning right a couple of times but mostly it's been in a straight line at low speeds (under 20mph). Roads have been fairly even I would say but your diagnosis sounds pretty accurate to me. Thank you - I'll discuss with dealer.
 

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Only had this about 5 or 6 times in 9 months of ownership. Sometimes it is immediately followed by the three beeps indicating an impending collision.

Once it occurred where there was a deep dip in the road immediately followed by quite a high traffic calming bump which makes me think its the emergency brake assist priming for operation. I was going about 20mph.

Once it happened when a dog on a lead lurched onto the road from a narrow pavement. On that occasion I was travelling at 30mph.

I have changed the sensitivity setting for the emergency braking assist so that its less sensitive. Rarely happens now unless there is a real chance of a collision.
 

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Discussion Starter #12
It's never been accompanied by the collision warning for me. I've had nearly 30 instances since March - 4 in one 11 trip recently. Good tip about sensitivity of emergency braking - I'll give it a try.

Thanks
 

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This is such a disconcerting grinding noise, often associated with loss of power momentarily, that if it happened on a test drive there is no way I would buy that car - that surely must be an indicator that it cannot be "normal". ?
This absolutely sounds like your driving (possibly). Sorry! You can adjust the sensitivity of the auto braking, maybe set it to low and you'll have less issues. I've had it in slow moving traffic where the person in front decides to hit the brakes and take a side road shortcut, if your following close and just feather the throttle a bit the car will on occasion prime the brakes, or prime the brakes and reduce power, or if your really close prime brakes, reduce power and bing up on the screen about collision detection. Generally the car will be set to normal Alert sensitivity in the Forward Collision system, but you can change this to high or low. You can also turn off Forward collision system, or turn out pedestrian auto braking.

Pedestrian braking is a thing too as I've mentioned, so if someone walks briskly to a kerb and steps then changes their mind you might get the system priming.
 

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I've heard a crunch sound from the brakes - maybe about 3 or 4 times so far - I've had the car 10 days. It happens at very low speeds - no warning signs after it. I thought it might just be part of the 'running in' of a new car....:)
 

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I live in suburban/semi-rural Cambridgeshire with narrow roads and lots of cyclists. I've had this grind when coming up behind cyclists to overtake (and I give them as much room as I can). Sometimes it can happen on a sweeping right hand bend if there are cars parked on the left and one is sticking out a bit. Sometimes it happens if the car in front starts slowing, and I slow, and then it indicates left quite late and I pass it slightly closer than the MG would like. This actually makes me think perhaps I should give things a bit more room anyway, one does tend to pick up bad habits with age!

I had that a few times on a loaner Toyota Prius PHEV, it would see the back of a parked car when driving on a right handed bend and it would panic and flash up "BRAKE BRAKE" on the dash!
 

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Discussion Starter #16
This absolutely sounds like your driving (possibly). Sorry! You can adjust the sensitivity of the auto braking, maybe set it to low and you'll have less issues. I've had it in slow moving traffic where the person in front decides to hit the brakes and take a side road shortcut, if your following close and just feather the throttle a bit the car will on occasion prime the brakes, or prime the brakes and reduce power, or if your really close prime brakes, reduce power and bing up on the screen about collision detection. Generally the car will be set to normal Alert sensitivity in the Forward Collision system, but you can change this to high or low. You can also turn off Forward collision system, or turn out pedestrian auto braking.

Pedestrian braking is a thing too as I've mentioned, so if someone walks briskly to a kerb and steps then changes their mind you might get the system priming.

No need to apologise - no offence taken. Sales rep from dealership drove it to garage yesterday and it happened to him - he says it was harsher grinding sound than he normally experiences on other ZSEVs he's driven coupled with loss of power.

Will try reducing sensitivity of forward collision system but that surely can't be a safe, permanent fix?
 

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Discussion Starter #17
I live in suburban/semi-rural Cambridgeshire with narrow roads and lots of cyclists. I've had this grind when coming up behind cyclists to overtake (and I give them as much room as I can). Sometimes it can happen on a sweeping right hand bend if there are cars parked on the left and one is sticking out a bit. Sometimes it happens if the car in front starts slowing, and I slow, and then it indicates left quite late and I pass it slightly closer than the MG would like. This actually makes me think perhaps I should give things a bit more room anyway, one does tend to pick up bad habits with age!

I had that a few times on a loaner Toyota Prius PHEV, it would see the back of a parked car when driving on a right handed bend and it would panic and flash up "BRAKE BRAKE" on the dash!
As most of my driving is in London there are always lots of possible obstructions in all directions.
 

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Zoe Devotee
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No need to apologise - no offence taken. Sales rep from dealership drove it to garage yesterday and it happened to him - he says it was harsher grinding sound than he normally experiences on other ZSEVs he's driven coupled with loss of power.

Will try reducing sensitivity of forward collision system but that surely can't be a safe, permanent fix?
I suppose it depends on your take of safe, if the car avoids an accident its absolutely safe. If it causes to one further behind you then not so much.

You might find it just goes away if you adjust the sensitivity to normal or low. I've found I drive a bit further back from people now, not much, 10ft more reaction time is enough for the car to perhaps prime only without it braking. Busy areas with a lot of pedestrian traffic will potentially be the biggest issue, although not so much right now as most folk are still generally staying indoors.
 

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Discussion Starter #19
I suppose it depends on your take of safe, if the car avoids an accident its absolutely safe. If it causes to one further behind you then not so much.

You might find it just goes away if you adjust the sensitivity to normal or low. I've found I drive a bit further back from people now, not much, 10ft more reaction time is enough for the car to perhaps prime only without it braking. Busy areas with a lot of pedestrian traffic will potentially be the biggest issue, although not so much right now as most folk are still generally staying indoors.
Sensitivity so far has been on normal but I'll switch to low and monitor for a while and maybe even turn off altogether.
 

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I had this before a FCWS alert (for traffic that wasn’t even in my lane, but whatever). Figured it was the brakes priming for an autonomous stop, glad i was correct :)
 
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