This is a really easy job to do on a Capri and replacement discs are cheap at around £30 a pair. From my experience most Capris approaching 100K miles will be ready for new discs. In any case they should be replaced if the disc is below 11.5mm thick. It certainly improves the brakes having nice new discs. Always replace the discs as a pair and if the pads are anything but nearly new then fit a new set of these as well.
First loosen off the front wheel nuts and jack up the front end of your car. With axle stand located on the front anti roll bar mounts remove both road wheels and place under the car. Next thing to come off is the brake calipers. It is not necessary to disconnect the brake hose to do this job but you will need to have something to hang the caliper off the spring and keep it out of the way. I use electrical wire which is nice and strong.
The overhaul of the caliper is described in detail in the work section. The caliper is bolted very tightly to the bottom of the strut by two large 17mm bolts. These will also have an anti-loosen plate attached, so the first thing to do is tap the metal flaps down with an old screw driver so you can get a socket over the bolt head. With a good heave, the bolts should loosen off. Carefully undo the bolts on the caliper and lift the whole assembly off the disc. You may need to rock and wiggle it about a bit and if it is stuck then you may have to remove the brake pads first. Tie the caliper up out of the way with strong wire so there is no strain placed on the brake hose.
Next job is to remove the hub which includes the brake disc. Prise off the hub-cap with a screw driver and clean away the grease that is hopefully still there. To remove the large hub-retaining nut and washer, first bend and extract the split pin and the nut cover. The nut itself is not on tight and once removed, the entire hub should pull away from the car. You will see that the outer wheel bearing also falls into your hand at this stage.
Spend some time cleaning up the hub - it will be packed with grease that should all be removed and replaced with fresh. If you turn the hub over you will see the four bolts that hold the brake disc on. The best way to remove these is to carefully clamp the hub in a workbench and tap the locking tabs down. Use a socket and undo all four bolts. The old disc normally needs a good clout with a hammer to separate it from the hub. Clean the mating surfaces up with some wire wool before locating the new disc in place. Refit the bolts and the tabbed locking plates and tighten progressively to 30-34 lbf ft before tapping the locking tabs back in place with an old screwdriver.
Before refitting the hub, pack the inside with a suitable quality grease. The bearings should also be well coated in grease so that it is worked into all the nooks and crannies.
You should now be able to re-fit the hub to the strut and fix in place. First make sure that all grease is removed from the new disc using a rag soaked in turps. The hub-nut should be tightened using the procedure described in the service guide. The brake caliper now needs re-fitting and this can be a bit tricky because the new disc is wider than the old. Use a block of wood in the caliper to push the pistons back as far as they will go. Don't be surprised if it is a tight fit! Re-torque the caliper bolts to 40-50 lbf. ft and tap the locking plates back in place. That's all there is to it but when you go for a test drive be very careful braking over the first few miles. Try some sharp braking in a quiet location and on a nice straight road. It will take a while for the pads and disc to bed in together so be on your guard. The brake peddle will eventually harden up nicely again.