On my MOT last month, it was picked up that the front discs were worn. I’d like to have them changed when the pads are due for renewal. Which brand of discs are the OEM ones, as I’d like the best quality parts considering the safety critical aspect of them. Equally, how much should it cost roughly to have them and the pads changed.

The original FoMoCo (Ford Motor Company) brakes are produced by ATE (a manufacturer that is owned by Continental). 

ATE also produces their own branded aftermarket brake parts which quality wise are comparable with the FoMoCo branded brake parts.
 

Avoid the motorcraft brake parts. The Motorcraft brand name includes a selection of approved aftermarket parts that are offered by ford as a cheaper alternative for the origial parts. Motorcraft brake parts are usually produced by Bosch and are not nearly as good as the FoMoCo/ATE brake parts.

Excellent, which one of these would be right for my car. Its just a 1.6 Mk2.

https://www.autodoc.co.uk/car-parts/brake-disc-10132/ford/focus/focus-ii-da/18302-1-6?sort_supplier[]=ate

I bought a mintex box set on ebay and they are very simple to install and have perfect braking and no squeals. You may want to paint the hub area tho as it tends to rust up pretty quick.

Brakes:

https://rover.ebay.com/rover/0/0/0?mpre=https%3A%2F%2Fwww.ebay.co.uk%2Fulk%2Fitm%2F141374701749

 

How to (for st but same principle): https://www.google.co.uk/amp/s/www.jamessimpson.co.uk/how-to-fit-focus-st225-brakes/amp/

Agree with Angus 😁 (Ian), fitted Mintex three times, OEM and no problems.  Unbelievable value at £50.

OEM parts doesn't necessarily mean the best quality... Brembo and Pagid both make equally as good discs and pads. Never had a problem with either.

Recently replaced front and rear original discs and pads (after 94 kmiles) with Brembo stuff. So far is good. Also have good experience with Delphi aftermarket.

My preference is Pagid...the discs come painted so there's no packing oil to remove and the painted hubs & edges remain rust free for longer than other discs.  Pagid pads also come with a break in compound on them which seems to reduce any risk of warping during bedding in.  So far I've not warped a Pagid disc at all, but my sister has managed to warp one after a couple of years.

Me and dad use pagid. I've fitted it on the front and rear when I was upgrading to ST brakes. 

'Worn'?  How worn?  Beware being conned into unnecessary work!  Our Mk 1 Focus auto estate front discs lasted nearly 100,000m,  only changed because pads (second lot - they should last around 40-50k unless you are boy racer)  needed changing.   Service the discs occasionally - take them off and hammer/grind off the rusty bits.   If you don't allow discs and pads to wear, you run the risk of calipers seizing because the piston hardly ever travels beyond the beginning of its cylinder, thus exposing it to corrosion instead of being bathed in brake fluid.

As above "Beware being conned into unnecessary work!

if the condition was a safety issue it would not have passed the MOT.

I don't know how much mileage you do etc.  or if the car is regularley left outside in the damp for periods without driving, letting the rust set in to the discs

My brother's 2007 Fiesta (previously my car) is now on 164k miles on the original discs but they are now looking a bit thin and uneven

these are bad discs:

https://mottester.wordpress.com/2011/02/19/pitted-brake-discs-again/

are yours even and shiney over whole surface on boh sides of each disc

 

Lots of choice! I don’t intend to change them for plenty of time yet, just getting an idea of what people use and how much they are. They’re the original 12 year old discs, only done 67k but they’re getting pretty lipped now. The brake pads will definitely need changing soon I think, beginning to  squeal now.

 

3 hours ago, JohnF said:

If you don't allow discs and pads to wear, you run the risk of calipers seizing because the piston hardly ever travels beyond the beginning of its cylinder, thus exposing it to corrosion instead of being bathed in brake fluid

I don't understand this statement. My understanding would be that worn discs and pads allow the piston to travel further out of its cylinder, beyond the seal, exposing more of it to the air (and moisture) and bathing less of it in fluid. I've had experience of a piston seizing because the exposed part of it and the outermost bore of the caliper both corroded.

If the exposed part of the piston becomes corroded then when it's pushed back during fitting of new pads/discs there's also a risk of it damaging the seal and/or resulting in a fluid leak.

Check the thickness of the disc in several places and compare to the specs. If it's uneven, below the minimum or there's a significant wear step, you should replace them. If not, they may still have plenty of usable life in them. How long the brake parts last depends on how the car's been driven.

20 hours ago, mjt said:

I don't understand this statement. My understanding would be that worn discs and pads allow the piston to travel further out of its cylinder, beyond the seal, exposing more of it to the air (and moisture) and bathing less of it in fluid. I've had experience of a piston seizing because the exposed part of it and the outermost bore of the caliper both corroded.

If the exposed part of the piston becomes corroded then when it's pushed back during fitting of new pads/discs there's also a risk of it damaging the seal and/or resulting in a fluid leak.

I agree with mjt.

Perhaps I should have clarified by saying  'exposing the unused wall of the cylinder in front of the piston to air and moisture'.  The disc and pads would have to be very worn indeed to allow the piston to protrude from the cylinder!  By wearing the pads right down to the 1.5mm allowance (or changing them as soon as you hear the dreaded metallic screech) you ensure that for much of its life the walls of the cylinder are behind the piston and thus bathed in brake fluid, so it won't corrode.   Hope all clear now.  It works for me - I have never had to replace a seized caliper.