MG5 Brake failure

There are two separate but related issues.
Firstly and a major concern to all of us, why did you suffer complete brake failure with a defect on only one of the split circuits. This is unacceptable and unsafe and is a design issue. We need to get to the bottom of this.

Secondly the poor installation of the flexible pipe which seems to be a one off. If the pipe is replaced pointing in the right direction then this issue is finished and will not reoccur.

If the dealer sorts out your flexible and checks fully there are no other assembly issues then that is the end of this problem and I suggest you would have a hard job rejecting the car as it is now fixed. You could ask for an independent inspection as a back up.

But that still leaves the issue of the design of the split system which, until a satisfactory explanation is provided, remains a question mark over whether the vehicle is fit for purpose.

Both issues should be flagged to DVSA. A recall would resolve the pipe rubbing issue. However the manufacturer would have to justify the safety of the design of the split system in event of a hose failure, which ultimately could require a modification to all cars.
Thanks, and agree on the split of issues. With regenerative braking, it is not possible for my wife to be 100% sure that there was complete brake failure. However she felt the brake pedal had zero resistance the moment it occurred. Also if MG technician says no brake fluid left in system where does that leave the "unaffected" circuit. We do just want to get comfort that if repaired the car is truly safe, perhaps an independent inspection might give us that comfort. Thanks for thoughts.
 
I would agree that an independent report by a third-party fully-qualified vehicle inspector is what you really need! If, eventually, you decided you were going to reject the car (perhaps on the grounds of severely compromised safety of the car's occupants) such a report might well be invaluable if your original dealer continues to refuse to accept that rejection and you decide to pursue the matter through the legal system.
 
Thanks, and agree on the split of issues. With regenerative braking, it is not possible for my wife to be 100% sure that there was complete brake failure. However she felt the brake pedal had zero resistance the moment it occurred. Also if MG technician says no brake fluid left in system where does that leave the "unaffected" circuit. We do just want to get comfort that if repaired the car is truly safe, perhaps an independent inspection might give us that comfort. Thanks for thoughts.
Guan147 I agree with emmrecs, and I have already said in more than one posting on this thread an independent report is your best bet, before if possible, and after any repairs are carried out, if it could be done before they would be able to decide why there was no fluid left in the brake system as the MG technician has reported, this should not be able to happen unless the master cylinder was at fault in some way or there is a fault in both circuits.
Les
 
The dealer who supplied the car is saying the dealer inspecting the car cannot provide them with a cause for the fault.
In that case then ( like I have said before ) the car needs to be returned to the ORIGINAL dealer, in order for THEM to do their own inspection and formulate their own opinions of the cause of events that caused this total brake failure.
Come on both dealers, it pretty obvious to me at least what has happened here, its an assembly drop off at the factory, pure and simple.
For reasons we will never know why, that flexi brake hose was NOT correctly located and then held in place by the retaining clip in that bracket, that is fixed to the body shell of the car.
The bracket likely had some type of defect, that prevented the retaining clip from being installed at the correct time in the assembly process ?.
Look at the picture, where is that all important retaining clip ?.
It never got installed - clearly.
So, the metal brake line gets fitted to the flexi ( regardless ) and is then tightened to the correct spec's.
But because the flexi is not secured to the holding bracket, the tightening affect of the metal brake line, has then in turn twisted both the metal brake line ( seen in the picture ) and the flexi as one item, towards the direction of the road wheel.
The necessary clearance between the brake flexi and the rim of the road wheel has now been greatly reduced and this foul condition has compromised the external wall of the rubber flexi.
Each time the pipe comes into contact with the wheel rim the brake line degrades even more.
Reaching the point where brake fluid then starts to leak each time the footbrake is depressed, slightly more fluid is slowly lost.
Then suddenly the wall of the pipe completely fails to the point where all foot brake pressure is lost instantly as all of the brake fluid has been ejected from the system.
I think it would take a vehicle inspector less than 10 minutes to come to a similar conclusion myself.
THE CLIP - THE CLIP is was never installed in the factory.
If you DO decide to have it independently checked and supported with an engineers report, I would suggest that you inform the original dealer ( in writing ) that is what you intend to do to support any future legal actions
As the dealer who is holding the car right now, is clearly distancing themselves from the situation and unwilling to get involved.
It is a "pass the parcel" situation unfortunately.
The dealer who supplied the car wants the holding dealer to pick up the baton, but he is too smart to fall for that one.
Here you are, stuck in the middle !.
 
I don’t have my manual to hand at the minute but there is a missing piece in the incident timeline. As soon as the brake fluid level drops below a certain point the low level alarm should go off and the driver should stop to nvestigate. I had a Citroen which was 100% reliant on a pressurised hydraulic system for brakes, steering and suspension. It suffered hydraulic failure twice. A huge red light came up on the dashboard which said in big letters STOP. As the handbrake was deliberately fitted to the front discs this was powerful enough to stop the car quickly. I have never tried using the MG electric handbrake when on the move. What happens? It would be reassuring to know.
 
Thanks, and agree on the split of issues. With regenerative braking, it is not possible for my wife to be 100% sure that there was complete brake failure. However she felt the brake pedal had zero resistance the moment it occurred. Also if MG technician says no brake fluid left in system where does that leave the "unaffected" circuit. We do just want to get comfort that if repaired the car is truly safe, perhaps an independent inspection might give us that comfort. Thanks for thoughts.

Hi

You would greatly benefit from calling the Citizens Advice, they will clearly define your rights and confirm your options. It is important you go through the correct process and comms are correctly worded for legal reasons. They are great to deal with and very helpfull.
I linked details in a similar thread (below).

 
I don’t have my manual to hand at the minute but there is a missing piece in the incident timeline. As soon as the brake fluid level drops below a certain point the low level alarm should go off and the driver should stop to nvestigate. I had a Citroen which was 100% reliant on a pressurised hydraulic system for brakes, steering and suspension. It suffered hydraulic failure twice. A huge red light came up on the dashboard which said in big letters STOP. As the handbrake was deliberately fitted to the front discs this was powerful enough to stop the car quickly. I have never tried using the MG electric handbrake when on the move. What happens? It would be reassuring to know.
The MG also has warning lights to show faults in the braking systems in fact I would say most vehicles on our roads do. Screen shot from hand book below with regards to this and the handbrake operation in an emergency.
Les

A6DB6A2A-A537-4878-83C9-D15B6EC051F0.jpeg

Also the handbrake
20A21B7A-F3A6-4792-9A09-BC3C18ED7A61.jpeg
 
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Thanks for your information. So various alarms should have come up when the brake leak happened. Would these be visible via a diagnostics search?
 
I don’t have my manual to hand at the minute but there is a missing piece in the incident timeline. As soon as the brake fluid level drops below a certain point the low level alarm should go off and the driver should stop to nvestigate. I had a Citroen which was 100% reliant on a pressurised hydraulic system for brakes, steering and suspension. It suffered hydraulic failure twice. A huge red light came up on the dashboard which said in big letters STOP. As the handbrake was deliberately fitted to the front discs this was powerful enough to stop the car quickly. I have never tried using the MG electric handbrake when on the move. What happens? It would be reassuring to know.

See this post linked below. The link takes you directly to post #20 in the thread, there is a little more info as you read on.

It was a ZS EV mk1 but I'm pretty sure all the MG EVs will be the same, but essentially pulling the EPB whilst moving applies the brakes on all 4 wheels and also uses ABS

 
The MG also has warning lights to show faults in the braking systems in fact I would say most vehicles on our roads do. Screen shot from hand book below with regards to this and the handbrake operation in an emergency.
Les

View attachment 15521
Also the handbrake
View attachment 15522
See this post linked below. The link takes you directly to post #20 in the thread, there is a little more info as you read on.

It was a ZS EV mk1 but I'm pretty sure all the MG EVs will be the same, but essentially pulling the EPB whilst moving applies the brakes on all 4 wheels and also uses ABS

I am not sure how this would work as the parking brake is electro- mechanical acting only on the rear callipers. I am reasonably confident there is no similar device on the front callipers. The parking brake has to be totally independent of the hydraulic brake system otherwise a hydraulic failure would take out all means of stopping.
 
It was a ZS EV mk1 but I'm pretty sure all the MG EVs will be the same, but essentially pulling the EPB whilst moving applies the brakes on all 4 wheels and also uses ABS
Thats very interesting indeed as the EPB in normal use, only holds each rear wheel independently when it is activated.
Each rear wheel is fitted with an electric handbrake motor, that functions each rear brake calliper.
It has no other means of preventing the car from moving, unlike the transmission lock on an automatic / DSG transmission.
 
I am not sure how this would work as the parking brake is electro- mechanical acting only on the rear callipers. I am reasonably confident there is no similar device on the front callipers. The parking brake has to be totally independent of the hydraulic brake system otherwise a hydraulic failure would take out all means of stopping.
Thats very interesting indeed as the EPB in normal use, only holds each rear wheel independently when it is activated.
Each rear wheel is fitted with an electric handbrake motor, that functions each rear brake calliper.
It has no other means of preventing the car from moving, unlike the transmission lock on an automatic / DSG transmission.
I was merely referring to a post/thread where this had been raised before and somebody said they had used the Park and also EPB whilst moving.
Perhaps someone else would like to try.
 
I was merely referring to a post/thread where this had been raised before and somebody said they had used the Park and also EPB whilst moving.
Perhaps someone else would like to try.
This screen shot relates to the affects of what happens if you apply the EPB on the move.

Here is the link to the full thread on the forum, it talks about pressing the "P" while driving at first, then covers applying the EPB manually via the switch.


EPB  2023-03-01 at 12.28.07.png
 
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Hi yes their was a long discussion about this over 18 months ago when I ask Miles Roberts what would happen if I accidentally pressed the park button while adjusting the drive or Kers switch while on the move and he got the same information as above in the screen shot above, was around the same time Miles did go on to try it and reported back nothing happens as in the post above.

Very strange this should pop up again as in my MK1 MG5 the selector was flat on top and needed a firm push down, but now I have the new MG5 it’s selector is more domed on top and very easy to press with very light pressure and its a little further forwards than before and more than once since I have this car I have seen the message on the screen which say something like slow to a stop to change drive selection.
This as happen as my wrist has caught the dome button while changing drive or Regen setting so In summery the cars will not allow you to go into park until you stop.
Les

Below is the the reply to conversation I had with Miles on the subject in April 21



Miles Roberts CG

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Apr 12, 2021
Hi Les,
Regarding the parking button. I have tested this at various speeds, and pressing the P button on the drive selector does nothing once the vehicle is above a snail's pace. I imagine that the limit is set to around 1mph, as pressing the button whilst rolling does nothing.

Kind regards,

Miles
 
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This screen shot relates to the affects of what happens if you apply the EPB on the move.

Here is the link to the full thread on the forum, it talks about pressing the "P" while driving at first, then covers applying the EPB manually via the switch.


View attachment 15566
Thank you for finding that, so @SCB86 was correct in his post concerning all 4 wheels being activated.
 
Hi guys sorry to randomly jump on this post, we have a mg 5 EV long range, it has been in the garage for over a month now as the steering as well as the breaks failed at the same time, thankfully we was at low speed and coming off the roundabout at 5am on the way to work.. the vehicle hit the kerb and somehow it just started to work again! The garage are now saying that they think they have found the issue and it’s linked to when the battery hits 50% they cannot allow it to leave the garage as they can’t guarantee the fault won’t occur again 😞 however it can’t be this as the vehicle was at 100% and 30 minutes into our commute to work! I saw this post and thought I’d bring it to peoples attention that clearly there is fault somewhere and is only a matter of time before others are potentially affected… thanks for reading
 
Hi guys sorry to randomly jump on this post, we have a mg 5 EV long range, it has been in the garage for over a month now as the steering as well as the breaks failed at the same time, thankfully we was at low speed and coming off the roundabout at 5am on the way to work.. the vehicle hit the kerb and somehow it just started to work again! The garage are now saying that they think they have found the issue and it’s linked to when the battery hits 50% they cannot allow it to leave the garage as they can’t guarantee the fault won’t occur again 😞 however it can’t be this as the vehicle was at 100% and 30 minutes into our commute to work! I saw this post and thought I’d bring it to peoples attention that clearly there is fault somewhere and is only a matter of time before others are potentially affected… thanks for reading
They probably mean the 12v battery.
 
Hi, I am new here, yesterday my wife was driving our 72 plate MG5 (facelift) and suffered complete brake failure, brake pedal went to floor with no resistance. AA attended and were horrified, all I know is a pipe was rubbing by rear wheel and they think eventually pipe failed and all fluid lost. Luckily my wife was driving slowly and regenerative braking was enough to slow to a stop. Car currently with main dealer. Not sure what to think about this as could have caused a serious accident and how all brakes can go without warning. Any thoughts?
Hiya.
Just joined to say I've had exactly the same problem. It was only delivered this morning. Heard rubbing on rear left.

Then brakes started failing. Thank you so much for posting this. I was about to pick my kids up 😳.

Brake fluid line is cut from placement on the tyre.
 
@ddz

Welcome to the forums!

You say It was only delivered this morning; is this a brand-new car or second-hand? If brand new you should be hammering on the sales desk at your dealers asking how on earth did they not spot this problem during PDI since it is highly unlikely to have started to wear only since you took delivery.

If it is a second-hand vehicle my question would be identical in tone and content, except that the PDI should now be the checks they carried out on the car before offering it on the resale market.

Whether new or second-hand I think your dealer has an awful lot to answer for; maybe you should also contact Consumer Protection.
 
I hope you get it sorted to your satisfaction.
On the back of this thread, I thought I should check mine. Looks fine and angled pipes are pointing up correctly.
Thanks
 
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