Does anyone skim brake discs any more?

[AnaloguePete]

Does anyone skim brake discs any more? Years ago, when I had an old ICE car, I had the brake discs skimmed to grind off the rough bits. There was also a minimum disc thickness that they could go down to. Is this no longer an acceptable practice?
I've just had my MG ZS EV MoT'd and the discs were the subject of an adisory, with a price of £450 to replace them and the pads. I know this is a normal price, these days, for a MG dealer fit, but I wondered if skimming was still allowed.
Thanks

 

[decrep]

The advice is, before a MOT, (and also as a regular practice) to use the friction brakes to wear off the inevitable corrosion, caused by regen not using the brakes.

 

[T1 Terry]

There will be a min size marked in the unmachined centre section od the disc, this is the min they can be machined down to for fear of warping or cracking/breaking. This is highly unlikely to ever be an issue with an EV as they use the brakes so little.
Might be worth ringing around the major brake places and ask if they still have a disc lathe, at the very worst, you could try a machine shop and see if they would be willing to do the job.

The reason for disc machining has nothing to do with grooves etc, it was to remove the work hardened surface that had a serious effect on brake performance and often resulted in brake pad squeal because the work hardened surface would burn the face of the new pads creating dust that caused the squeal .....

I have seen ruff and ready mechanical repairers use a flapped disc on and angle grinder to make a new flat surface, not the recommended method

T1 Terry

 

[JohnV6]

Melvyn Rutter the Essex Morgan dealer has a machine to do this

 

[Lovemyev]

The fiction material on the original pad's ( although not worn out ) are going to be pretty cut up by the corrosion on the disc’s.
So, even if you get the discs skimmed, the pads are going to need replacing anyway.
Therefore the cost of skimming vs replacing is going to be minimal.
Discs and pads are readily available for the ZS EV from third party stockists now at a much more affordable price than the dealer replacement parts.
The discs and pads are nothing out of the ordinary tbh.
I would consider going down that route myself.

 

[T1 Terry]

The fiction material on the original pad's ( although not worn out ) are going to be pretty cut up by the corrosion on the disc’s.
So, even if you get the discs skimmed, the pads are going to need replacing anyway.
Therefore the cost of skimming vs replacing is going to be minimal.
Discs and pads are readily available for the ZS EV from third party stockists now at a much more affordable price than the dealer replacement parts.
The discs and pads are nothing out of the ordinary tbh.
I would consider going down that route myself.

The pads on a sheet of sandpaper cleans them up fine, but worth checking out the difference in price between the machining and aftermarket replacements ...

T1 Terry