Brake discs

[jollyman]

I have checked them myself. I am quite capable, having completed an MG K3 from a wreck to pristine running order, so there is nothing I have not stripped and restored on a car, but this MG4 is only one year old!!!

 

[KMC]

I recently took my MG4 SE for its first service at the dealership who informed me to check in six months that I my may need to replace my brake discs. Is this normal after only 4,500 miles? Are they made of Weetabix or cardboard? I have run discs up to 30,000 miles in the past and replaced them myself. Is the dealership pulling a fast one thinking that I wouldn’t know any better? Are they short of work? Has anyone else experienced this or am a first? I will get a professional to check them out first, perhaps the Chinese make theirs from butter.

Run your finger pad from top edge to bottom edge on your disc. If there is a ridge top or bottom the disc is thinning, if it feels flat the dealer is taking the micky. I will be amazed if they need replacement after 4500 miles & would put a better manufacturers discs on. No way would I stand for oem again thats shocking!

 

[Bricktop X PWR]

I have checked them myself. I am quite capable, having completed an MG K3 from a wreck to pristine running order, so there is nothing I have not stripped and restored on a car, but this MG4 is only one year old!!!

So am I missing something?

You have checked them?

They are fine?

Ignore the bloody dealer!!!

 

[Kithmo]

A few years ago SWMBO was told by a Toyota dealer that her rear discs needed changing on her old 2006 Prius when they had only been changed the previous year. It still passed the MOT so I told her to leave them and I would change them if needed. When I checked them they had surface rust on, as she didn't use the car much and it was sometimes left standing for a week at a time. I cleaned them up with some rough emery paper and they came up fine. For the next 3 or 4 services and MOTs there was no mention of them again and the same discs were still on the car when she traded it for the MG5. I think the dealer forgot they had changed them the year before and just decided they were due for a change regardless of the condition.

 

[Lovemyev]

Replacing brake discs & pads on EVs has become a bit of a money spinner if you ask me!
Especially if there are no third party replacements on the market.
I think the saying goes :- “Making hay while the sun is shining”.

 

[Macadoodle]

Replacing brake discs & pads on EVs has become a bit of a money spinner if you ask me!
Especially if there are no third party replacements on the market.
I think the saying goes :- “Making hay while the sun is shining”.

Yip, tis all about the revenue they need to generate to keep the workshops viable, getting more difficult with the increase in EVs.

I stripped the rear brakes on mine over the weekend as the rear discs continue to show a really uneven contact with the outer pad.
Around 40% of the outer surface of the disc gets rusty, suggesting that the outboard pad is not being pulled evenly onto the disc, the other side of the disc is where the piston pushes the pad directly is bright and evenly worn.

Removed the sliders and their rubber guides and thoroughly cleaned them before reassembling with lots of silicone grease, although I did the same last year and still the uneven wear persists ?
All the pad contact points are clean and lubed too.

I think it might be a design flaw with the caliper rubber inserts that the pins slide in, they're unusually thick and span the entire bore so I wonder if the caliper twists slightly as force is applied, making the outer pad contact at a slight angle.

2 pot calipers would have been the answer but even the x power didn't get them so fat chance of that I guess

 

[Lovemyev]

Yip, tis all about the revenue they need to generate to keep the workshops viable, getting more difficult with the increase in EVs.

I stripped the rear brakes on mine over the weekend as the rear discs continue to show a really uneven contact with the outer pad.
Around 40% of the outer surface of the disc gets rusty, suggesting that the outboard pad is not being pulled evenly onto the disc, the other side of the disc is where the piston pushes the pad directly is bright and evenly worn.

Removed the sliders and their rubber guides and thoroughly cleaned them before reassembling with lots of silicone grease, although I did the same last year and still the uneven wear persists ?
All the pad contact points are clean and lubed too.

I think it might be a design flaw with the caliper rubber inserts that the pins slide in, they're unusually thick and span the entire bore so I wonder if the caliper twists slightly as force is applied, making the outer pad contact at a slight angle.

2 pot calipers would have been the answer but even the x power didn't get them so fat chance of that I guess

I agree, the problem with the single piston type callipers, is that the trailing friction pad ( the outer pad ) is slightly slower to react and therefore the braking requirements are pretty much satisfied by the inner pad, before outer pad becomes effective.
Without the regen braking effect, this would be minimal I guess.
Remember the ZS EV has been derived from the ICE model that has no Regen effect.
I think you have done everything in your power to eliminate the build up of rust etc on the rear discs.

 

[AndyNWuk]

I recently took my MG4 SE for its first service at the dealership who informed me to check in six months that I my may need to replace my brake discs. Is this normal after only 4,500 miles? Are they made of Weetabix or cardboard? I have run discs up to 30,000 miles in the past and replaced them myself. Is the dealership pulling a fast one thinking that I wouldn’t know any better? Are they short of work? Has anyone else experienced this or am a first? I will get a professional to check them out first, perhaps the Chinese make theirs from butter.

I took my ZSEV into Chorley Motors in Burnley for its third service and first MOT last September.
I pay a monthly Service Contract of almost £16.00 but brakes etc are not covered.

They told me it needed complete rear discs, even though the car at that time had only done 6,500 miles. The cost of the new discs and fitting was just over £400.00

They also told me it was very common with EV's for this to happen as its the electric motors that often slows the car down when in Regen mode 3 but it was advisable to do the first few miles of your journey in Regen 1, which will use more of the Disc Brakes and keep them polished.

I have to say, I was shocked to have to pay out so much after such a low mileage and age, but it made sense what the Service Department told me, so I have changed my way of driving and use the Regen 1 more often now for the start of my journey then switch over to Regen 3.

 

[Lovemyev]

They told me it needed complete rear discs, even though the car at that time had only done 6,500 miles.

This situation on a three year old car that has only covered 6.500 miles, is the main problem combined with high regen levels TBH.
Low mileage user cases are going to suffer more, than a higher mileage user cases unfortunately.
Facing a bill of £400.00 to replace rear disc's and pads is a bit easier to accept, if you have covered say 40,000 miles rather than a mere 6,500 miles !.
The cost is identical for both cars, but the value for money is a lot less in milage terms.
The OEM equipment is nothing special really and is well over priced.
It will continue to be so, until more third party replacement parts becomes more available.

 

[Tuareg]

you can have the discs skimmed for much less money. They don't even need to be removed to have them skimmed, special portable machine that good garages will have.

 

[deejay]

When I got my first car, a Fiesta, I had it serviced by the dealer every time. Every time new brake pads. I didn't know any better. This went on for nearly four years. Then I moved house and took the car to a different dealer. Suddenly the brake pads were lasting twice as long and the services overall were costing little more than half what they had previously cost.

The Ford dealer in Welwyn Garden City had been ripping me off. It happens.

Well, well what a surprise!

 

[Helena999]

We've had our LR trophy for a year, done 20k miles and had a service. No problem with brake pads and no recommendation for a change soon.

 

[jollyman]

We've had our LR trophy for a year, done 20k miles and had a service. No problem with brake pads and no recommendation for a change soon.

Brilliant just what i would expect thanks very much for your input

 

[salty]

If there replacing them for nowt, let um do it. If as the the replies on this thread and you yourself suggest, tell them politely (Or not) to, do one! ???

 

[Tig170]

We've had our LR trophy for a year, done 20k miles and had a service. No problem with brake pads and no recommendation for a change soon.

Out of interest what re-generation do you run ? - in that I decided to have a look at mine this afternoon (given all the comments) - the rears were in quite bad shape (in that only 60% of the rear discs were shiny) - We've done nearly 20,000 miles and always ran on 100% regen - anyway dropped regen to low, and did a few bedding in stops until i got the discs hot (& smelly) - now much better in that the pads are more even, and the discs are almost shiny all over again - so will just keep off the regen over the next week to see how things smooth out on the pads. Fronts were fine.

 

[Lovemyev]

Out of interest what re-generation do you run ? - in that I decided to have a look at mine this afternoon (given all the comments) - the rears were in quite bad shape (in that only 60% of the rear discs were shiny) - We've done nearly 20,000 miles and always ran on 100% regen - anyway dropped regen to low, and did a few bedding in stops until i got the discs hot (& smelly) - now much better in that the pads are more even, and the discs are almost shiny all over again - so will just keep off the regen over the next week to see how things smooth out on the pads. Fronts were fine.

Try picking one day a week when you are conducting a longer journey and then try dropping the Regen to the lowest setting for the whole day.
I find this works for me at least ?.

 

[Tig170]

Try picking one day a week when you are conducting a longer journey and then try dropping the Regen to the lowest setting for the whole day.
I find this works for me at least ?.

Cheers - will do! - We only really do out of town miles, so do very little active braking - nevertheless it does surprise myself as to how the pads can become so out of shape. Clearly they are just not getting used.

 

[JonnyG]

.............I stripped the rear brakes on mine over the weekend as the rear discs continue to show a really uneven contact with the outer pad.
Around 40% of the outer surface of the disc gets rusty, suggesting that the outboard pad is not being pulled evenly onto the disc, the other side of the disc is where the piston pushes the pad directly is bright and evenly worn..........

Yep, that's what I'm getting on my rear discs. Even after some hard braking sessions to remove the rust there is uneven wear towards the outer edge with slight scoring.

 

[Macadoodle]

Yep, that's what I'm getting on my rear discs. Even after some hard braking sessions to remove the rust there is uneven wear towards the outer edge with slight scoring.

Yup, looks pretty much like mine. RWD EV's really should be fitted with rear drums or 2 pot calipers for more even pressure on each pad.
The motor is doing the majority of the braking on the rear unless SOC is really high.

The design of these SAIC produced calipers seems particularly prone to uneven pressure on the outer pad though

 

[Tig170]

Yep, that's what I'm getting on my rear discs. Even after some hard braking sessions to remove the rust there is uneven wear towards the outer edge with slight scoring.

Ditto - 20k miles in (fronts are quite even though?)