existing discs or new ones. From my experience, Morgans do not cause a lot of disc wear as the car is relatively light. Compare a Morgan with the weight of a Range Rover and you'll understand what I mean.
There are two things to consider: wear and runout. Wear is detectable by a ridge on the outer and inner edges of the disc. If there are 'steps' it's a fair indication of wear and possible replacement. Runout is the amount of 'wobble' or sideways distortion in the disc. Excessive runout causes the pads to 'kick-back' the pistons into the calipers and is generally caused by excessive heat. It's easily detectable by pulsating of the brake pedal under braking or more accurately by placing a guide next to the outer edge of the disc and spinning the disc in situ on the car.
If the wear and runout are slight or undetectable, then save your money for other mods that will improve your car or wellbeing! Malt whisky is a pleasant 'mod' but incompatible with driving!
