When my VW Passat was last serviced I was told that the front disks had corroded. This is true and there has been some corrosion at the edges. I have been reluctant to change the disks, as neither the disks or pads are near their wear limits, even after 45,000 miles and 5 years. The brakes work fine.
However, the car is now due for its MOT, so my question is: Is the state of the disks an MOT failure point?
Yes.
I'd be inclined to whip the wheel off and tap the outside edge of the disc with a hammer whilst rotating it to remove the lip of crud that accumulates.
If the discs are 8 quid each, and the pads not far from the same, with the wheel off you could possibly be as well just replacing them. That's the usual crap reply for "just replace it anyway" amateur-diagnosis, however it's been 5 years, and a new set wouldn't go amiss. Otherwise, whack a hammer with a good edging on it around the outside if you feel sure they're not worth replacing quite yet.
Unless the car has been unused for some time the only corrosion you get is where the pads don't touch the disc - and this doesn't matter. A few good applications of the brakes will remove any surface corrosion where they do touch. If it doesn't you have a seized caliper which really will fail the MOT.
Trouble is, even on Euro car parts the cost of the pads and disks is £80! I will take another look with the aid as it is now a few months since the car was serviced. I expect to wear brakes out rather than just have them rust away.
Reason for rejection:
"a brake disc or drum insecure, cracked or excessively scored, pitted or worn"
See here, section h:
Chris
gsf are very cheap for bits like this, depending on the model the discs are
15 quid or a bit more.To fail an mot the discs would have to be very corroded. Put it in for a test and see what happens
I'm surprised to hear this. All brake discs that are more than a few days old will have some corrosion round the edge. How much constitutes an MOT failure? I've never had an MOT tester mention discs to me during the test and most of them must have been corroded at the edges (the discs, I mean!).
Rob Graham
Have you read the rest of this thread? Specifically, the parts where a number of respondents have reassured the OP that edge corrosion will not be a MOT failure? The ones that were p[posted three days ago...
Chris
Michael Chare was thinking very hard :
Corrosion on the no (pad) contact areas of the disk is normal and no reason for concern.
If the all the pad contact areas are clean, with no extensive grooving and the thickness of the disk is within spec., you have nothing to worry about.
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