They go between the flexible brake line coming off the caliper and the hard brake line on the frame. You should use line wrenches when working on the brake lines cause the nuts on them are soft (made of brass). Then ofcourse you have to bleed the brake system.
'87 YJ, 4.2L built and bored, 8.5" of lift, 8.8 rear, AX15/NP 231, Tom Woods drive shafts, Flat fenders, 12,000LB winch, Custom bumpers, Rattle can paint job. Never completed...