ZS MK UK Replacement rear discs and pads

[decrep]

It's quite likely all you need to do is use the brake pads on them for a change, and wear the surface rust off. Too much regen, mixed with water can quickly lead to a rusty looking disk.
Seems MG UK are aware of this, and try and get you to fork out unnecessarily.
There's no regen in neutral, reverse or at 100% charge. find a quiet hill and just brake gently until the squealing stops.

 

[Lovemyev]

This condition is the negative side of utilising the Regen facility on all EV’s.
Braking using the footbrake is a 80 - 20 ish condition, about 80% of the braking is conducted by the front brakes and the remaining 20% is done by the rear brakes.
Therefore the rear brakes never really display the same level of use / wear that the front pads and discs do.
Add strong Regen into the mix on an EV and the rear brake have almost nothing to do at all.
This lack of use allows rust to form that then develops into deep pitting into the face of the disc’s.
It hasn’t taken long for both dealers and MOT testers to lock onto this premature corrosion problem and it is offered them an opportunity to take some much needed lost revenue from EV owners.
Service time for EV’s have become more of a “Health Check” than replacing engine oil / filters etc etc.
They are NEVER going to let this work opportunity pass them by tbh.
There no real solution to preventing this condition or it repeating itself again unfortunately.
Turning the Regen to its lowest setting will help prevent the decline speed of the rust forming, but most of us like this feature so it’s a battle between head / heart and ultimately your wallet .
I tried once a week, to remember to lower the Regen to its lower setting to help with the rust, but it’s not a cure .
On the ZS EV the car defaults to normal Regen and that became my “Go To” setting.
Our S5 on the other hand, it defaults to LOW Regen on start up, this may help a little in the battle of surface rust forming .
Our ZS EV had covered about 28,000 miles in the three and a half years of ownership.
It passed its first ( independent ) MOT with no problems at all and nothing was reported by dealership on any of the 3 annual service inspections it had.
There was “pitting” clearly evident on the surface face of the discs on the rears, so I expected it would get picked up at some time in the near future.
I think owners would complain less, if the price to replace this items at the dealership, was not so expensive !.
The is nothing really special about this discs or pads, very basic standard stuff.
Now third party replacement parts are available at a highly discounted price point.

 

[Andy L]

Trying to find "third party" disks seems to be a minefield ,even though I have the part numbers from MG and put these in ebay I get a match and then further into the listings it states not compatible with epb versions! They then go on to describe them as 280mm dia but Grok is adamant they are 260mm and Grok has matched the dimensions to an mg database. Going to have to take off a wheel and check for myself I think unless anyone on here has the actual size?

Oh and as for using regen 1 and using the brakes more I have done that quite often and after 43k miles the pads show 40% wear and corrosion has still occurred. In comparison the fronts are still showing 10mm pad thickness and minimal wear on the discs.

 

[Lovemyev]

Oh and as for using regen 1 and using the brakes more I have done that quite often and after 43k miles the pads show 40% wear and corrosion has still occurred

Yeah - I did say this above, more use of the footbrake ( less regen) helps slow the progress of deterioration, but it will not prevent the inevitable unfortunately.
The pads would have very little wear under normal conditions, but wear is accelerated because the contact brake surface of the discs to pad material is SO rough ( caused by the pitting and corrosion) that it cuts the material like a cheese grater.
I did upload the info on part number compatibility on another thread.
Removing the rear wheel and measuring will be the best option.
If my memory serves me correctly, the Gen1 and Gen2 models use the same brake disc.
The part number at MG will change IF there is a price change ( I have seen this with other items ).
Some discs are listed as 5 hole and others at 10 hole.
Pretty sure the ZS EV are 5 hole versions tbh.
Here is an example of some of the Borg & Beck discs available.
A lot less expensive than the dealer parts.

 

[Andy L]

Yeah - I did say this above, more use of the footbrake ( less regen) helps slow the progress of deterioration, but it will not prevent the inevitable unfortunately.
The pads would have very little wear under normal conditions, but wear is accelerated because the contact brake surface of the discs to pad material is SO rough ( caused by the pitting and corrosion) that it cuts the material like a cheese grater.
I did upload the info on part number compatibility on another thread.
Removing the rear wheel and measuring will be the best option.
If my memory serves me correctly, the Gen1 and Gen2 models use the same brake disc.
The part number at MG will change IF there is a price change ( I have seen this with other items ).
Some discs are listed as 5 hole and others at 10 hole.
Pretty sure the ZS EV are 5 hole versions tbh.
Here is an example of some of the Borg & Beck discs available.
A lot less expensive than the dealer parts.


View attachment 40929

They can wait until the summer now ,thanks for the info though.