Firstly find a piece of tubing. I used some of the blue pipe that connects water
filters. It is 1/4" or 6.5mm diameter.
You will also need a piece of 1/4" (6.5mm) diameter dowel/wood
And a pair of tweezers/long lose pliers.
Cut a piece 5mm in length. See below
After removing the old O ring and cleaning the inside of the hose. Insert the
blue tube in the hose so the hole of the tube is over the Schrader valve.
Squeeze the O ring in half and push inside the hose.
Use the dowel and push the O ring down until it pops into place.
Remove the blue tube with a pair of tweezers.
All up it should take you around 30 seconds to insert the O ring.