Loud braking noise with MG Pilot, and roll back on hill

[mcsmartie]

My father's one month old ZS EV is making a loud, strange, disconcerting noise when the MG Pilot is decelerating, especially when coming to a complete stop (traffic jam assist?). Only tested in KERS mode 3. It doesn't make the sound when using the brake pedal.

The best way I can describe it is a loud creaking, akin to on old hand brake being pulled up, occasionally followed by a thud,

Also, the cars rolls back a little on the slope before the pilot/traffic jam assist brings the car to a complete stop. Is that normal?

Here's the dashcam footage you can hear the sound its making, and see the roll back:




I've read about a brake pump noise, but it can't be that loud?

It's booked in next week at the dealer to be checked, but just wondered if these sounds and the slight roll back are normal?

 

[LoneRanger]

The Brake Pump sounds like a grating of gears in an Austin Maxi from the 1970's.

I think it is less prone to doing it when the ACC is set to its greatest distance, as it gives the car more time to prime the brakes.

 

[Kithmo]

Sounds normal to me, mine does it, that's why I stopped using it because it's embarrassing.

 

[Cocijo]

It’s the brake pump. That’s the noise it makes I’m afraid. You’ll also hear it under emergency intervention if the car thinks you’re going to hit so something

 

[ARealHuman]

Yep I get that as well. Every time it startles me and every time the missus - if she's in the car - asks what the hell it is. It does indeed sound like something is broken and not working properly, but going by the several posts on here about it, "they all do that, Sir".

 

[LeoRBK]

I experience the same with the car. This happens when car tries to bring itself to a halt. I think you do not hear it when car tries to slow down. My initial suspicion is emergency braking is triggered because MG Pilot would not slow down the car in time. It is sometimes slow to realize a car in front is slowing down and hence emergency brakes trigger.
I assumed it is as per design. I was going to talk to my dealer to confirm. I think weak brakes could cause this.

 

[mcsmartie]

Thanks everyone for the replies.

Yes, that's the noise @Chestnut2000 a 70's Austin gearbox crunching. Maybe SAIC have found a use for old MG parts they inherited in our EVs

I found one other video of if traffic jam assist (in Dutch, you can see he resumes ACC at 2:02) -




I can only hear slight creaking when his car is decelerating to a stop. Nothing as loud/shocking as in my video. Could just be his microphone is not as sensitive to this particular sound.

Will try increasing ACC distance.

 

[macd2401]

Fwiw, it's the same noise it makes if you try an emergency stop using the handbrake switch.

 

[Kithmo]

Fwiw, it's the same noise it makes if you try an emergency stop using the handbrake switch.

C'mon, admit it you were trying to do a handbrake turn.

 

[macd2401]

C'mon, admit it you were trying to do a handbrake turn.

Well, mibbe just a little bit

 

[Gomev]

My father's one month old ZS EV is making a loud, strange, disconcerting noise when the MG Pilot is decelerating, especially when coming to a complete stop (traffic jam assist?). Only tested in KERS mode 3. It doesn't make the sound when using the brake pedal.

.....

In case you weren't aware (as I see you have just joined the forum), when using ACC or MG Pilot, there is no regenerative braking. The car uses the brakes only to slow down so whichever KERS you are in is irrelevant.
As you aren't using the hydraulics by using the pedal - normal braking - then the car has to use a pump to activate the brakes, replicating your foot action.
I hope that makes sense, and I'm sure someone will add to or correct if necessary.

 

[Cocijo]

I think under normal use when travelling at higher speeds, under ACC or MG pilot, the hydraulic disc braking system operates quietly and stops the car going over the set speed. It‘s at low speed where the noisy pump kicks in - perhaps because more force or urgency is needed? I used to put lollypop sticks in my bicycle spokes when I was a kid that reminded me of the braking pump noise.

 

[cog16]

I experience the same with the car. This happens when car tries to bring itself to a halt. I think you do not hear it when car tries to slow down. My initial suspicion is emergency braking is triggered because MG Pilot would not slow down the car in time. It is sometimes slow to realize a car in front is slowing down and hence emergency brakes trigger.
I assumed it is as per design. I was going to talk to my dealer to confirm. I think weak brakes could cause this.

I have just had a horrible experience which is related to emergency braking.
I am in France and went on my first long journey the other day. Going to Bordeaux on the autoroute, using ACC at 110 kph. Due to accident ahead, all three lanes full and slowing down, the ACC braking often, (and I pressing brake pedal at last minute because I wasn't 100% confident) and ACC managing stop start at between 50-70kph. The ACC then went into Emergency braking on a long uphill slope. Came to a halt, with my foot on pedal.
When car in front moved off, I lifted my foot off pedal and it started rolling back. Car behind honked, but I braked and it stopped. Noticed parking light was on. Tried lifting foot but rolled back again. Hazards on and cars went around me ( I was in outside lane). Lifted foot , roll back. Tried changing out of drive to neutral and reverse and then back again, then lift foot , rolled.
Tried turning off - no reaction.
After about 3 minutes, lifted foot and it started forward, and able to continue journey ( with ACC off!).
Return journey not via autoroute thank you.
Spoke to MG HQ in Paris, who said that after extreme emergency braking, it would go into a Safety state, but he was surprised that it rolled back. Told me to take it in for diagnostic of what happened ( all is recorded onboard apparently). At local (new) dealer, their only person trained was on holiday for 2 weeks, (it's that time of year), and I have an identical car(called Luxury model here) for at least 2 weeks , with huge MG cals.
Sorry if this is long but a lot happened in a short time

 

[Cocijo]

It sounds like a stressful experience. The ZS will roll back on a slope unless the hill hold assistance (for a limited time) and/or Auto-hold engaged. You know auto-hold is on when the green brake light illuminates on the dash.

 

[cog16]

Cocijo .When one is in the situation I was in, one doesn't have time to notice the little light on the dash! I hope never to do that again. It didn't help that my somewhat doubting partner was with me!

 

[Cocijo]

Oh dear!

 

[Kithmo]

Braking turns off the ACC but not the emergency braking.
You rolled back because you had turned off ACC by braking.