I ride a nice simple road ss. brakes are your usual single cable from levers to brake mech. My son has a road/BMX - POS, weighs half a ton.
Rear brake is kaput - the mechanism is unbelievable - cable comes out of the lever, into a pipe , two cables come out, though the headset, into a ring - some no-tangle mechanism - that's loosely connected to another ring, from there down to another pipe - so now back to a single cable, then on to a linear-pull mech.
And it doesn't work. The springs work on the mech, but it doesn't spring back at the lever - too many interfaces and places to go wrong. Any suggestions? (that don't involve the local dump and pointing him at a real bike)
you can copy answers direct to firstname.lastname@example.org if you feel inclined