Richard, it depends on where the chrome is deteriorating. If it's in the area of contact with the pad or pad shims or in front of the dust cover then I wouldn't worry too much.
If it's in the area behind the dust cover or particularly where the piston enters the bore definitely not as it will probably stick, leak or both.
They're easy to get new and it's possible to get stainless ones too..
I can't remember the caliper model number; M16's were fitted to Plus 8s and from memory were common to Escort Mk1s and Mk2 and Cortinas.
By the way, it is possible to split the caliper; it's how these calipers were converted to accept ventilated discs. Be aware that they are not unknown to leak after being split.
Kevin Vernon's not too far away from me. Interesting what he said about rear discs and I wouldn't despute his logic for road Morgans. I converted my car to read discs as after converting to a Dellorto carburated 3.9, I went through a set of hard compound brake shoes in both practice and race. That's eight sets of shoes just for one event! After three event and twenty four shoes down to the rivets I decided enough. Rear discs pads were not consumed with the same appetite!
Enjoy the tinkering. I'm tinkering with making up some easy-fit race mirrors just in case I get the chance to 'go out to play' again this year.
