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MG5 Brake failure

guan147

Standard Member
Joined
Feb 16, 2023
Messages
9
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11
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6
Location
Oxfordshire, England
Driving
MG5
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?
 
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?
First of all, I am glad to hear that your wife is fine and nobody was injured !.
It must have been SO scary for her.
No fluid, means no brakes.
I am a little surprised that the car did not detect the fluid loss and report it ?.
It sounds like one of the flexible brake pipes have failed for some reason and by your post, it sounds like the flexible hose has been rubbing, which could be a routing problem ?.
Too early to spectate of course, but I am 100% sure that other members will be interested to hear what happens next please.
A meeting with the dealer is forgone conclusion at the very least I would suspect.
Possible recall on the cards here ?.
 
First of all, I am glad to hear that your wife is fine and nobody was injured !.
It must have been SO scary for her.
No fluid, means no brakes.
I am a little surprised that the car did not detect the fluid loss and report it ?.
It sounds like one of the flexible brake pipes have failed for some reason and by your post, it sounds like the flexible hose has been rubbing, which could be a routing problem ?.
Too early to spectate of course, but I am 100% sure that other members will be interested to hear what happens next please.
A meeting with the dealer is forgone conclusion at the very least I would suspect.
Possible recall on the cards here ?.
Thank you, yes children were in the car too so very concerning what could have happened at different speeds etc. Yes the pipe was rubbing and presumably until the instant it broke and fluid was lost there was nothing the car could alert us to? I am mostly unclear and concerned how it is possible for all brakes to fail in this situation rather than just the rears if there are dual circuits? I saw another post from another member reporting the exact same issue and they returned the vehicle. Knowing this has happened twice suggests something requires investigation. I will update here as discussions continue with the dealer.
 
I am really glad to hear that everybody involved are safe and well !.
The thought of approaching a zebra crossing and not being able to stop have been blocked completely out of my thoughts 🤯.
I am really surprised that the car is not equipped with a very basic “Low Brake-fluid” level warning light TBH ?.
Had this been the case, the low fluid warning light would have activated and the driver would have carried out a visual inspection of the brake fluid level WAY before the level in the reservoir dropped SO that it completely ran out of brake fluid ?.
Surely it has to be a factory assembly issue ?.
 
Last edited:
Didn't someone on here post a picture about the dangerous proximity of the rear brake hoses to the wheel last year ?
Edit: this is the post:
Rear Flexible Brake Pipes
Well remembered and well spotted @Kithmo .
Quick recap of what @stuart57 rear brake hose looked like when it failed around April 22nd 2022.

Brake Hose MG5 2023-02-16 at 19.18.47.png
 
Dual circuit braking systems have been around for many many years some to the 60s it used to be one of the items that manufacturers would advertise in there brochures as being one of the latest safety systems some where separate circuits for the front and the rear others had nearside front and off side rear as on circuit and the other too wheels as the other so I find it very to believe that a modern day vehicles would not be fitted with a dual circuit set up so this scenario to me is mind boggling I will most certainly be have a good look at my car tomorrow. Below is a screen shot from the handbook which says there is a brKe fluid warning light on the dash. But I can’t find any mention of the braking specifications. And has pointed out by Alb #6 there are question to be asked here. What ever next is going to turn up with these cars.
Les


EDAACD8D-593A-4BD3-BCD3-93F48A6AF747.png
 
Thank you everyone for your feedback. I spoke to the dealer and MG UK today about our incident and there seems to be very little concern that this warrants any action other than repairing our car but I await full report from the technician inspecting it. The MG5 manual does describe dual channel brake system, see below. The MG app started sending me hundreds of alerts but only after the brakes had failed completely. We are unsure if we will keep the vehicle.

DD1E493F-8A4E-4BE8-BB89-EB6A8AE5CE33.jpeg
 
I knew it would be I don’t think any vehicles are being built today that don’t have this so ok when you have lost the brakes in one circuit why did the other not still operate to some degree this is very strange indeed, Please do post the report when you have it if I where you I would demand a full report in writing please do keep us updated I’m very pleased to hear no one was hurt in anyway.
Les

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?
Hi guan first I forgot to say welcome to the forum and thank you for your horrific posting has to what happen with you car, as we have established in the posts earlier the car is fitted with duel circuit braking systems so to me the only reason for a brake pedal to hit the floor like you described is a total failure of the brake master cylinder I’m not surprised in the lease the AA where horrified this should never happen especially on a new car.
Les
 
@guan147 Is it possible that your good lady mistook the extra pressure and increased travel if one circuit had gone for the pedal going to the floor. ?
I only ask as your original post also mentioned that 'Luckily my wife was driving slowly and regenerative braking was enough to slow to a stop' This will not happen of course as the MG5 does not have one pedal driving and braking is required to actually stop.

Anyway it is not a good experience and glad no-one was hurt.
 
Applying the brake pedal will introduce regen won’t it? In the event of a complete friction brake failure applying the brake pedal will increase regen as it normally does won’t it?
 
The brake module (it's obviously more complex than a conventional master cylinder) on the 5 is a Bosch component (it's written on it) so likely to be used on many EVs. I guess it would be possible to find out more about its functions if you dig deep enough on the net
 
You will see it on the regen indicator as you brake.
 
Many years sinceupon I had a brake issue in my Renault Espace. There was a split circuit valve that failed. It was common to both parts of the split circuit and we lost all foot brake.
Managed to survive with a gingerly applied right foot, loads of predictive driving and judicious use of the handbrake (fortunately only over a few hundred yards).
Green Flag pitched up, pronounced a brake problem which they "didn't ever fix at the roadside" so we got flatbedded back from Preston to Luton.
It was the fastest I'd ever done that run. The guy flew!
Wouldn't stop for a cuppa either. He was back in the truck and away.
 
Applying the brake pedal will introduce regen won’t it? In the event of a complete friction brake failure applying the brake pedal will increase regen as it normally does won’t it?
Regen does happen on the 5 when braking, but regen alone will not bring the car to a halt.
 
Hi everyone, just catching up on the replies, thanks everyone for your thoughts. The latest situation is that the vehicle was recovered to our local MG dealer (not the dealer who supplied the vehicle). The dealer who has the car initially were treating it as a simple warranty repair, however we are considering rejecting the vehicle via the dealer we purchased from. It has taken until today to receive the inspection report from the dealer technician who have the car. They also sent the following two photos:

20230216_091844.jpg
20230216_091735.jpg


The report is as follows:

1677064786486.png


Our main concern is that given other owners reports of similar issues/concerns for how this pipe is positioned/secured that there is a design fault with the MG5 in general, or whether there is a fault specific to our actual vehicle.

I am awaiting a response from the dealer we bought from to see if they will accept our request to reject the vehicle for full refund. The car was purchased in December and has approx 2000 miles on it.

Even if the car has been repaired under warranty, we have lost confidence in the car and will be replacing it with something else.

Any further thoughts / advice on how to proceed with dealer appreciated. We really hope we don't have to start moving the vehicle and arranging independent inspections etc.

Thanks!
 
It definitely looks as if the angled coupling is orientated incorrectly as it should be vertical. Here's a pic from my car taken back in 2021:
brake pipe.jpg
 
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