[motto]

For what use it is Bob, the GMC 6x6 CCKW used a similar brake hose set-up on all of its six wheels. The hoses ran direct from chassis to wheel cylinders with a support spring to hold them up.
The springs were produced specifically for that purpose and may possibly be the same item as used on your truck. They are quite easily stretched and were of an unusual construction having the hook at each end made from heavier wire and loosely retained by means of the spring ends being wound in a cone shape.
The captive end of the hook was bent back on itself and could not come out through the hole in the conical end
CCKW parts vendors may still have them.

David