checking brake discs

[thelawnet1]

Want to put new pads on my car, got an MOT advisory for 'worn, pitted or scored' brake disc on the same axle (it doesn't say near or offside though). Not sure what I should be looking at, only thing I can find is that the discs are 22mm new and replace at 20mm, though not sure how to measure these. Also replacement discs seem to be ~£20 to ~£50 depending brand not sure if it makes a difference, and 'left' and 'right', but one site sells 'left' and 'right' but only lets me buy two (surely you'd want 1x left and 1x right?)

Nearside


Offside


Also offside

[thelawnet1]

E-bmw said:

My advice to you would be next time take it elsewhere, there is nothing wrong with them!

I can't comment on the pads obviously, but in discs of that condition I would be surprised if they are badly worn.

Can you see the depth of pad material left?

Well the pad doesn't look great I think? (failed <1.5mm)

[thelawnet1]

227bhp said:

The description says 'worn, pitted OR scored' and yes they are worn out, you can see a mm or so of lip on just one side.

is there a loss of efficiency between 22mm (new), 21mm (part-worn) and 20mm (replace)?

[thelawnet1]

227bhp said:

Don't fall into the trap of thinking an MOT is something to try and get around or a tiresome expense, the attitude should be 'Thanks, you've just highlighted something that will be dangerous given time'.

Well there's always a balance. On the one hand you might as well do them both as labour is significant part of the cost, on the other I only do 4500 miles a year so it's not really clear they will ever become dangerous as long as I own the vehicle, and then on the other it's only another £60 or whatever (depending on brand).

And so on.
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[thelawnet1]

I actually ordered some discs, but they came too late and turned out I had some pads kicking around that were supposed to have been fitted previously.

have now been fitted by the axle on which they were fitted is making a sort of squealing noise, just driving along 1 mile or so from garage. Not sure if that is normal and they should settle down or?

[thelawnet1]

SebringMan said:

It may be the lip catching the old discs. Or the pads are seized into the carrier ; did you have to force the pads in with more than hand pressure and were they free to move on the carrier?

I dunno I didn't do the pads. However all seems ok now, so it must have just been a newly fitted thing.