Typically disc brakes on small trucks use 3/16" lines, but not always, you need to check.
If you use a dual circuit MC now that has very similar outlet locations to the MC you will use with he disc brakes (you may even use the same one?) Then you probably can use the same hard lines for both versions of the system. The flex lines may change length and or end design to fit the calipers.
Also think about the proportioning valve if you use one.
Pretty much if you use the same stuff or same size and shape parts for both systems then the lines will be reusable, you can figure it out by looking at the components.
I have put together two trucks with stainless lines I bent and flared, it's a lot of work and can be frustrating.
A better option is a copper-nickle alloy, sold by these folks as "Cunifer"
http://www.fedhillusa.com/ At first I thought it was pretty expensive, but after using it and also stainless the slightly higher price of the copper-nickle line is well worth the ease of use and reduced frustration. I don't plan to use much if any stainless line any more.
You can get it cheaper on ebay from UK
http://shop.ebay.co.uk/items/_W0QQ_nkwZkuniferQQ_armrsZ1QQ_fromZR40QQ_mdoZ about half price after figuring exchange rate and shipping. I'll try them when I need to order more. The folks at fedhill are nice, but some competition would be good for the prices (but obviously not for them).
Grigg
