First Service ... Excessive Corrosion of the rear Disc found

[JuziWomble]

This was flagged on the First Service - I've asked the dealership surely this is a warranty claim as the Brakes are clearly malfunctioning - Thoughts ?

Excessive Corrosion of the rear Disc .... Its being monitored - But to me the brake setup was at build and at no point have I had the need to be anywhere near them ? so the Pad isn't in full contact to the Disc hence the leadng edge has the corrosion on - No idea on other side - That wasnt shown on health check - So I guess we can assume its in better condition ....

 

[Kithmo]

It looks like the pads are too small or incorrectly assembled, my rear discs are shiny almost fully to the edge.
I'd definitely expect a warranty claim on that, it's not wear and tear.

 

[JuziWomble]

Cheers as I thought ...

 

[JuziWomble]

It looks like the pads are too small or incorrectly assembled, my rear discs are shiny almost fully to the edge.
I'd definitely expect a warranty claim on that, it's not wear and tear.

Both rears are the same - i.e both look as if there is a miss alignment or SMALL pads !

 

[Alb]

I'd say there was something wrong with the pad. They should be inspecting with the wheels off.

 

[JuziWomble]

I'd say there was something wrong with the pad. They should be inspecting with the wheels off.

It was flagged on first service (Friday) as a monitor - I'm back with the ZS in a few weeks - So will raise it again if I haven't heard back from my email to the service team before then (I expect to) ..

 

[AndyNWuk]

I have just had my ZSEV Mk1 third service and was told the rear brake disc hubs needed changing due to corrosion, which was NOT a warranty claim, even though my car had only done 5,800 miles from new and the bill came to just over £400 which I was not expecting.

After research both on here and other EV Forums, evidently it is very common for EV's brake discs to corrode which is due to the regenerative braking system.

When keeping the regen on high like I was (Number 3 all the time) you rely mainly on the electric motor to slow the car down rather than using the foot brake.

I believe also I read that using the MG Pilot more often even when travelling around town, also uses the main disc brakes rather than the motor to slow down or stop, but I tend to only use the pilot for the odd motorway journeys.

The discs become rusty as they are not being polished and corrosion sets in.

I have now taken two steps with my ZS EV, firstly I travel the first part of any short journey using REGEN 1 which polishes the discs nicely and after washing the car, I spray the discs with an anti corrosion inhibitor called Bill Hammer ATOM-MAC and so far no signs at all of corrosion on the new replacement discs, even though I live just off the promenade on the coast in Blackpool !

This video gives you more info about ATOM-MAC.

Andy

Blackpool

ATOM-MAC

 

[tsedge]

On my MG4 I use Adaptive regen, which seems to use the brakes more often. We are by the coast too but no sign of any corrosion so far.

 

[AndyNWuk]

Interesting, you don’t have the choice of adaptive braking on the ZS EV mk1, only Kers 1, 2 or 3.

We have just taken delivery of an X Power last week so it will be interesting to see how it performs against the ZS EV mk1, but again we run the first part of the journey in REGEN 1 then adaptive or 3 to make sure the discs get polished to prevent corrosion.

 

[tsedge]

It could also be because I drive the car fairly hard, so it does get its share of heavy braking.

 

[JonnyG]

There's many tips out there from existing EV drivers to do a weekly hard braking session (when safe) from high speed to get the pads and discs working hard.

 

[fnegroni]

Did one last night: regen on 1, brake pedal on Sport. Make sure road is straight.

 

[siteguru]

As I (almost) always charge to 100% then mine always gets brake usage to keep them clean. It doesn't matter what regen level you set - when you're at 100% SoC there's no regen anyway.

 

[JuziWomble]

My image was showing that the rear disc is used - but only 90% of it - the outer 10% is clearly being missed ...

However, we have had it where the older Leaf needed its brakes 'sorting' as we put it in Park (It had three drive modes Park/Drive/B eco Drive) but never used the handbrake lol and the re-gen wasnt 'strong enough' .. We now use the Handbrake (or Foot-Handbrake)

 

[fnegroni]

I checked my rear brake discs and I can see the outer edge is less used, and it’s pretty obvious. I wonder if it’s to do with how the pads sit on the disc making contact with less of the pad material unless braking hard.
I have a little bit of rust from the rain earlier today, and I’ve been out for a quick drive. I’ll check if the pad ever made contact with the outer edge.

** UPDATE **
The pad made contact with the entire disc, removing the rust on the outer edge, yet it remains pretty obvious that the pad isn't hitting the whole disc uniformly: somehow there is less pad contact on the outer edge.

 

[JuziWomble]

I checked my rear brake discs and I can see the outer edge is less used, and it’s pretty obvious. I wonder if it’s to do with how the pads sit on the disc making contact with less of the pad material unless braking hard.
I have a little bit of rust from the rain earlier today, and I’ve been out for a quick drive. I’ll check if the pad ever made contact with the outer edge.

Makes me think ' Google - How do I do a Handbrake turn in a EV - Specifically an MG4' ..

 

[JuziWomble]

Mine Goes in on the 9th Jan for the rear discs to be checked - I have been trying to 'brake more'... Dealership is aware that I'm not accepting on a year old car that this normal and fair wear ... Clearly the Pads are not cleaning the Entirety of the Disc & haven't been (loan car booked) ....
ZS in with them on the 19th of this month - So I will see what's what with the latest purchase

 

[JuziWomble]

Had a 'spirited' country lanes drive home (and was mindful of Deer as they are local and v.common) - Selected 'Custom' with LOW regen selected ... 20 miles later - Seems to have buffed the outer edge of the Disc - Or at least it looks as if it has !

Will leave it in Custom and select LOW regen for the next few days (Sod the Eco runs lets have some dark winter night country lane fun) & see if Its fixed it ... - Might also remove the blasted trims to see the Disc better...

If having it set on LOW has sorted the Discs - Then surely that's a case of a design fault - Makes me ponder if this is why VAG have gone back to Drums on the rears of the ID.3 & Born

 

[siteguru]

RWD EVs don't really need disc brakes on the rear as most of the braking action (except under heavy braking) is performed by regen. Of course with a high battery SoC there's little to no regen in the MG4 until the SoC comes down.

 

[fnegroni]

Had a 'spirited' country lanes drive home (and was mindful of Deer as they are local and v.common) - Selected 'Custom' with LOW regen selected ... 20 miles later - Seems to have buffed the outer edge of the Disc - Or at least it looks as if it has !

Will leave it in Custom and select LOW regen for the next few days (Sod the Eco runs lets have some dark winter night country lane fun) & see if Its fixed it ... - Might also remove the blasted trims to see the Disc better...

If having it set on LOW has sorted the Discs - Then surely that's a case of a design fault - Makes me ponder if this is why VAG have gone back to Drums on the rears of the ID.3 & Born

I’d rather have discs all around and occasionally brake harder at lower regen. Best is custom with sport braking and low regen or adaptive regen whenever you fancy cleaning the brakes.