Brake discs

jollyman

jollyman

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exeter
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MG4 SE SR
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.
 
How often have you been doing progressive braking? The problem with EVs and regen braking is that the brake pads and discs don't get a lot of use, so they can rust etc. It is recommended to regularly (once per week?) find a clear opportunity to use your brakes hard - this helps to keep the pads and discs clean. Set regen to level 1, get up to a reasonable speed, make sure all is clear around you and then stamp on the brakes (like an emergency stop). Do that 2 or 3 times and your brakes should clean up and braking performance be improved.
 
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.
 
jollyman said:
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.
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condition of front and rear discs are generally easy to see, with. a small mirror you can normally see the material left on the pads as well

they need replacing when worn (easy to see a lip on the out edge) or heavily corroded (easy to see the black rust pitting)

pads are normally recommended to be replaced when 3mm or less material left

if you see neither of these ask for a reason why they think they need replacing and consider using a different garage / dealer for servicing
 
Regen doesn't work below a certain speed (5mph ?) so the friction brakes are active.
That's how my car gets a little disc clean every day as I back off my drive slowly with my foot covering the brake to control the speed as the car creeps backward.
I've never had to replace discs purely due to rusting in 50 years of motoring, only on wear and tear.
 
jollyman said:
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.
Click to expand...

Sounds like your having your pants pulled down.

And nobody wants that?

Do you want to post up a picture?

My cars has done 5000 miles and I stripped and checked my brakes last week.

They were absolutely fine and nowhere near needing anything replacing.

I was just being nosey.

Ignore the rusty look.
I drive through a Ford in my garden to get to my drive, and they always get wet, hence looking rusty.
20240219_113244.jpg


Edit : My front pads have twice the thickness left available than what you can see on my rears.
 
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Kithmo said:
Regen doesn't work below a certain speed (5mph ?) so the friction brakes are active.
That's how my car gets a little disc clean every day as I back off my drive slowly with my foot covering the brake to control the speed as the car creeps backward.
I've never had to replace discs purely due to rusting in 50 years of motoring, only on wear and tear.
Click to expand...
When braking lightly like you describe here, almost all of the (light) brake force goes to the front wheel brakes. Not much happen on the rear brakes until a harder press on the pedal. If you are able to keep the rust away from the rear discs like that at all, the pads will much easier cease up. Some hard brakes from good speed is the best help for the brakes longevity.
 
With regular charging to 100% in SR - regen braking is dead for a while until the battery depletes a bit. Seems to keep me using the friction brakes hard as the amount of times I forget and have to stamp on the anchors last minute is shockingly regular.
 
WoodPecker said:
Hello, I'm new to the forum. I'm picking up my Xpower hunter green next week. I'm very interested in the topic of brake pads. Do you know if there are Pagid-type pads that are more "bitey"? Thanks in advance for your response. I'm slowly discovering the forum...
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Alright Pal.
I haven't looked tbh.
I've found that giving the brakes a 'good clean' early on in your journey sets you up for the rest of the day.

Just looked and don't see anything aftermarket listed for the X Power yet.

I'm sure something will be along soon.
 
MSvirus said:
When braking lightly like you describe here, almost all of the (light) brake force goes to the front wheel brakes. Not much happen on the rear brakes until a harder press on the pedal. If you are able to keep the rust away from the rear discs like that at all, the pads will much easier cease up. Some hard brakes from good speed is the best help for the brakes longevity.
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over on the Hyundai IONIQ forum we identified this 5-6 years ago,

the fix is to find an empty quiet, wide, straight road with no camber and get the car up to 50+mph / 80+kph and gradually brake harder right down to 0, repeat a couple of time every couple of months (and just before the car goes in for service)

gradually braking harder reduces the risk of loss of control

this keeps the discs clean and also prevents the callipers from seizing due to little use

hard braking requires all 4 friction brakes as the regen braking can't provide the level of braking requested

as with all things like this, its the drivers responsibility to ensure it is safe to do and the vehicle / road surface are in good condition etc etc
 
siteguru said:
Something to consider? No idea if they do them for the MG4 though.

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It could be a problem with the electronic brake system like on the MG4, as the electronics are calibrated to the frictional coefficient of the brake pads that come standard, and will probably throw that off quite a bit. I already see the brakes on my car grabs harder than they should when lightly braking to a standstill, the regen does most of the job but when right before standstill the disc brakes takes over and it lugs harder, even if same force is applied to the pedal. So a software update should be done on that even. Would probably be bad with hot high performance pads...
 
MSvirus said:
When braking lightly like you describe here, almost all of the (light) brake force goes to the front wheel brakes. Not much happen on the rear brakes until a harder press on the pedal. If you are able to keep the rust away from the rear discs like that at all, the pads will much easier cease up. Some hard brakes from good speed is the best help for the brakes longevity.
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Not "almost all", IIRC the braking force on cars is normally distributed somewhere between 60% : 40% and 80% : 20% front to rear and tends to be nearer the 60 : 40 on rear wheel, rear engine (motor in this case) cars. So a good proportion of my braking is going to the rear wheels. Even if it was only 20% at least it's some.
 
jollyman said:
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.
Click to expand...
What regen do you use. I always use the highest and hardly ever have to brake.
 
Very interesting post and replies....

Even so, 4500 miles is no mileage at all.... seems very unlikely!!!!
In grateful for the information regarding a forced brake to keep the brakes clean and active. Most interesting as a new MG4 owner.
 
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Thanks everyone for your comments. They are all helpful, but it’s not about discoloration or excessive braking, it’s about normal amounts of wear after normal brake use after only 5,000 miles. I have changed brake discs and pads in the past, on many vehicles, but only after much use, i.e. 25,000- 30,000 or more. So why are my main dealers recommending or advising to check discs after only probably 8,000 miles by June or July???
 
jollyman said:
Thanks everyone for your comments. They are all helpful, but it’s not about discoloration or excessive braking, it’s about normal amounts of wear after normal brake use after only 5,000 miles. I have changed brake discs and pads in the past, on many vehicles, but only after much use, i.e. 25,000- 30,000 or more. So why are my main dealers recommending or advising to check discs after only probably 8,000 miles by June or July???
Click to expand...

Just look at them yourself.

Pull off the wheel trim and use a pen torch to help you see.

Extremely easy to see if your discs or pads need changing.
 

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