At last MoT my so-far trustworthy local garage reported slight corrosion on front brake discs of my 2018 Karoq. Next MoT due on 27 May - am I in for a big bill? 

Not really because slight corrosion is not a MOT failure and what is needed is the brakes to pass the brake test at the MOT. 

Discs and pads are not expensive and the trustworthy garage could change those if or when the time comes.

 

As it is maybe have the brakes serviced, and the brake fluid change was at 3 years then 5, but the garage can maybe test the brake fluid to see it has not got too much H2o content. 

If your car has been standing for even a few days it is usual for the brake disks to have a thin covering of rust. Applying the brakes a few times usually clears it. Perhaps your MOT tester is commenting on rust other than on the disk faces?

Whatever the outcome  as Roottoot says the cost or replacing the disks and pads is not too high.

Thanks for that. Will know in couple of weeks.

@DBAY  Does you car not get any servicing or maintenance  between MOT's or pre MOT with someone with training and knowledge looking the car over?

Edited 12 May, 20224 yr by roottoot

If your discs do need replacing you could use Big Bill. But equally any Skoda trained motor technician could do the job!

It’s a common con to catch out non mechanically minded owners.

The discs can look bad so it is easy to convince  owner to carry out unnecessary works.

As long as the disc is still above the minimum thickness it is ok. Some serious braking quickly removes the rust stain on the area swept by the discs. A rusty edge may remain outside of the swept area.

Of more concern is seized pads on rear of car on some models. Yetis were very prone to this as brakes on rear never used that hard.