The fabric covered "bleed-off" hoses between the injectors dry out over
time, crack and leak.

Measure the entire length, buy that length and replace the hoses, one at
a time so the length(s) can be cut to the correct length. Use a utility
knife to cut away the old ones being careful not to nick the hose barb.
Push the new hose onto the barb using a pliers. There may be a stub end
with a small steel plug inside, insert the plug into its stub end hose
before pushing that hose onto its injector.