Support the tailgate in the open position with the help of an assistant, or using a stout piece of wood.
Using a suitable flat-bladed screwdriver, release the spring clip, and pull the support strut from its balljoint on the tailgate. Note which way round it is fitted.
Similarly, release the strut from the balljoint on the body, and withdraw the strut from the vehicle.
Refitting is the reverse of removal, but ensure the spring clips are correctly engaged.
Do them one at a time so that you've got the other to refer to.
ChicksFan, May 2010
