SCRUNCH at low speeds?

teepee

Member
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?
 

Frank

Well-known member
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?
Hi,

All normal apparently. You may or may not be aware that for the servo assistance of the brakes to work they need a vacuum which is normally provided by a petrol or diesel engine (a by product of the normal workings of said engines) however you don't get that from an electric motor so there are pumps on our car which come on occasionally to provide this vacuum and this is what you are hearing. It actually mentions these noises being heard on the MG FAQ page about ELEC cars.

I hear the noise and a couple of other members have also reported it, so it is NOT an issue.

Regards

Frank
 

Frank

Well-known member
Hi Teepee,

This is it from the MG Webpage, MG ZS EV FAQS:-

Q. SOMETIMES A PUMPING NOISE CAN BE HEARD WHEN APPLYING THE BRAKES. WHAT IS THIS NOISE?
A. This is entirely normal. Because there is no petrol or diesel engine, the brake vacuum assistance needs to be provided by a separate electrical pump. The noise is simply the pump working to assist the brakes. Because MG ZS EV is a very quiet electric vehicle, it means that the pump can be heard more easily.

Note, usually when I hear the noise I am applying (pumping!!) the brakes , but only hear the noise and very slow speeds and because others hear it it is unlikely that it is a fault but as stated the pumps working. I am surprised that the dealers does not know this however in his defence as you only hear the noise occassionly they have probably not heard it themselves, it would be interesting to hear if they come up with something else!!!!

Regards

Frank
 

teepee

Member
Thanks Frank - my concern is that it doesn't really sound like a vacuum noise - more of metal on metal clunk. Especially early on it was very loud and disturbing but has settled down since. It does happen when simply driving along without touching the brakes and it has occasionally slowed down the car momentarily. Hopefully its not a problem is very disconcerting. Let's wait and see what they say this time round.
 

Frank

Well-known member
Tom,

Yes I have had all that as well and I was worried until finding out that others like yourself have heard the same sound (assume it is the same sound) and after reading the FAQ I surmised (as did my dealer) that it was the (lets call it the servo pump) pump making the noise especially as a few members had voiced this concern and therefore unlikely to be a fault, not impossible but unlikely.

However taking all that into account there is no problem with a dealer investigating the noise just in-case it is not a pump.

All engineers and companies when designing cars have a battle with Noise Vibration Harshness (NVH) entering the cabin and affecting the refinement!!! of the car. In ICE cars lucky for the engineers a lot of the NVH concerns are masked by their engines but due to the near silence of EV Motors the Engineers have a much harder time containing the NVH from entering the car. For example the Jaguar I-Pace has users reporting horrible noises when braking on their cars and Polestar 2 (Volvo) had to redesign their wiper motor as it was too noisy.

One wag on here who reported the noise and accepting it was the pump(s) just stated "if you don't like it just turn up the radio"

I ignore it when I occasionally hear it and if it is a problem I will let the warranty deal with it. The car is going in for its service on Nov the 11th, I am going to ask the technicians if they can force the servo pump (maybe they can vent the vacuum on the brake servo in some way) to operate to see how noisy it is. Like the polestar 2 maybe MG should invest in a redesigned and quieter pump.

All the best.

Frank
 

Paulie68

Active member
I get that too. It's not the normal vacuum pump noise, which is a separate, quieter, and more pleasant sound. Mine did it yesterday, but sometimes I don't hear it for days, one day it did it several times in one trip. It sounds bloody awful but seems to be normal.
 

Frank

Well-known member
I get that too. It's not the normal vacuum pump noise, which is a separate and more pleasant sound. Mine did it yesterday, but sometimes I don't hear it for days, one day it did it several times in one trip. It sounds bloody awful but seems to be normal.
Hopefully Teepee's dealer will confirm what it is (if they can replicate the noise) once and for all but you are right it does sound awful. I (unless its my imagination) actually feel it through the floor of the car as well as hear it!!!!

Regards

Frank
 

Paulie68

Active member
Hopefully Teepee's dealer will confirm what it is (if they can replicate the noise) once and for all but you are right it does sound awful. I (unless its my imagination) actually feel it through the floor of the car as well as hear it!!!!

Regards

Frank

I'm pretty sure I get a power reduction as well just as it makes the noise, no idea what it is, but at least they all do it. If it was just mine, I'd be freaking out! I bet it's hard to replicate during a dealer test drive, as it's often so infrequent.
 

teepee

Member
I'm pretty sure I get a power reduction as well just as it makes the noise, no idea what it is, but at least they all do it. If it was just mine, I'd be freaking out! I bet it's hard to replicate during a dealer test drive, as it's often so infrequent.

Likewise I sometimes get a momentary power reduction.

Have told the dealer to keep it for a week if needs be so he can give it a good test drive. Picking up courtesy car in the morning (fingers crossed)
 

teepee

Member
Hopefully Teepee's dealer will confirm what it is (if they can replicate the noise) once and for all but you are right it does sound awful. I (unless its my imagination) actually feel it through the floor of the car as well as hear it!!!!

Regards

Frank

You're right it does sound awful, and it is accompanied by a drop in power/breaking effect at times. It surely can't be normal? Let's hope they do get to the bottom of it and not just try and fob me off.
 

teepee

Member
Just a thought...... If the car had made these noises (and associated power loss) when I test drove them (drove 2 different cars) it is so disconcerting that I would not have bought the car.

It would seem that the ABS/AEB vacuum priming itself noise is normal but I suspect much quieter than I am experiencing - let's hope the car "performs for them" when they test drive it.
 

Bobby759

New member
I noticed the noise especially if you are in traffic and close to the vehicle in front and without braking I thinks its the ABS. Mine did an emergency stop for me when some muppet decided to stop mid left turn, I had it covered as I was mid overtake but the noise made me jump as I wasn't expecting it, I didn't know it did that anyway.
 

Mark Holmes

Well-known member
Yes I know the sound you mean I have had that a few times, particularly if a car slows in front and the car feels I haven’t slowed sufficiently, it can be quite sensitive, but it’s also adjustable in the settings.
 

teepee

Member
Will try adjusting the sensitivity to low to see if it improves. I did get the salesman to drive my car and he did agree he experienced the harshest reacton in my car that he has come across so far - and I'm assuming he will have experienced a few different cars. I'm yet to be convinced that this is "normal" behaviour for a new car. Still awaiting answers from the dealer so will keep you all posted with news as it develops.
 

Mgkev

Active member
So weird, we’ve had our MG since January but my wife came back today complaining of a strange grinding sound she’d never heard before. Later today I took the car out and experienced the same noise that I’d never heard before either. I’m sure it’s the same as discussed here but strange that it’s only started today. Both incidents were at low speed just around the time of light breaking.
 

teepee

Member
Mmmm....the plot thickens.....

I suspect you mayhave the same issue.

My dealer has referred this back to MG as he has experienced the same issue in their loan vehicle and he is awaiting a response from MG.

Meanwhile, I have followed advice from this forum and reduced the sensitivity on the forward collision system (go into car settings and scroll across to forward collision system) from normal to low and have done a couple of short trips (at low speeds - only approx 20 miles total so far) but I have heard no scrunching yet.

Fingers crossed!! But will certainly be interesting to see what MG come back with.
 

Mgkev

Active member
Hi Teepee, I thought the noise came from the area where the brake master cylinder is located so I wouldn’t be surprised if it is an issue with the brakes or the booster pump pressure.
 

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