MG ZS failed on excessively corroded brake pipes

You have hit on a real problem for MOT testers here. There is no way for us to make the measurement we need to make for the official failure criteria. IT IS NOT PHYSICALLY POSSIBLE. This means that except for a few really obvious examples, they are all down to the best judgement we can use given that the brake pipes go up under fuel tanks and suspension units etc. Now when I tell you that a brake pipe which is pitted to a depth of 10 thousandths of an inch fails, does that give you any idea of the scale of the problem? My personal opinion, given that from the photographs there are some areas which I might fail (obviously going from photographs is a hopeless task in itself), is that your man has been irresponsible in saying it should not have failed. It is, and has to be, the opinion of the man actually doing the MOT AND NOBODY ELSE, not even another experienced tester. Next, I will ask you, given that this is your braking system we are discussing here, is it worth the arguing? The pipes are corroded. Again going from your photos I would say there is more than surface corrosion. If mine failed I would replace them and be happy knowing that there is now no problems there to worry about. One final thought on the subject. I find it is ALWAYS the original MOT tester who is believed to be wrong in any situation such as this, and never the second fellow. Always.

from what I can see from the photos theres a couple of areas that I might pull but as mentioned above without seeing what they looked like in situ its hard to tell,given your stated vehicle its almost always the ones running above the tank,its a bmw design and they rot precisely the same,pulled many over the years.

I find, if you take the old brake pipe & bend it on a rusty section, you'll find it will break very easily. You'll be able to see the depth of the corrosion and also how thick a brake pipe is ( even in good condition ) it's scary how thin even a good one is, when you consider what they do!!

Wisdom beyond your years

0.7mm is the thickness of a NEW brake pipe.

Judging by the pictures only, I’d likely have passed those BUT they are clearly safety critical and you’ve had the work done now so there’s no recourse anyway.

Pay up, move on, sleep well. (And perhaps find a garage you trust next year)

Some people just take their cars away , paint them, sand them down, grease or under seal them rather than change them, what would make you feel safer and give you peace of mind.

Mot’d a Range Rover today, after doing decel test parked it in workshop printed ticket off failed on a few bits. After pulling it out noticed a puddle of brake fluid on workshop floor pipe burst above undetray. Moral of the story is don’t take chances with brake pipes and advise undertrays fitted. If I had parked it in the car park I probably wouldn’t have noticed.

I've had a discovery burst a pipe through corrosion on it's first test..... he wasn't very happy !!!