Sorry intended to reply to you earlier today, but got sidetracked picking up our real 4wd, instead of that silly xtrail toy.
We picked up a nice hilux dualcab 4wd ute, so getting the boat to and from the beach will be a breeze.

Anyway tracking back to your request, the cap stays attached to the webbing sewn to the strut, you just need to force the nipple back into the strut, squeeze hard and push firmly, it will go in.

When you reinsert the bladder, either tuck the pointy end of the bladder inside itself, or pull it into the strut by the method shown in the instruction manual.

Use plenty of talc, inflate to 50% and massage into place, inflate to 75% check it is in right, if not remove and start again. Don't just blow it up hard first up, good chance you will blow the bladder if there is any misalignment.

Cya and

Goodwinds

Steve McCormack