Why is fluid or air leaking from my swivel?

Why is fluid or air leaking from my swivel?

O-ring worn out or wrong O-ring for material being handled

Replace O-rings with O-ring kit or replace with correct rings for material being handled.

Swivel may be loose or not enough pipe thread sealant on shaft threads

Remove swivel and check threads ensuring they are in good condition.  Reapply thread sealant and install swivel onto reel ensuring good thread engagement.