There are 2 types of wet bolt. They are 9/16 A full size over its length and a reduced size with a shoulder that uses a 7/16 " sized nut. Both use thread locking nuts. They work equally well the issue is when you use the ones with the shoulder they can only be used with standard thickness shackles as they are intended to be tightened all the way to the shoulder which leaves a little play for the spring.
With the full size wetbolts you can use heavy duty thicker shackles that have better grip on the knurling, to prevent locking in the spring. The trick with them is to tighten the lock nut to full torque, then back the nut off a 1/2 turn to allow the spring to move between the shackles.
The bolt must never twist in the shackle.
Our '09 carriage 5er had dexter axles with mor ryde rubber equalizers. The morrydes did not have a 'tube' between sides. ' bolts were dry. They quickly wore through the equalizer, left us broke down for days at a tow truck yard to get new parts. $$$$