This item was pre-installed as picture.
It is consisted the follwoing parts. Metal trunnins; 4mm strut wires; side pin; and collars
This metal trunnion not only able use for 90 rotate retract, as well as use as normal trunnion of convensional retract, as long as you use a set screw fix the strut wire to lock it not be moving.
It also able use for steerable retract trunnion as long as use a steering arm with e-clip fixing the strut wire (not included)
The side pin come with this upgrade kit is use screw thread fixing to the strut wire, it is more easy for install to the strut wire.
If you use it for the regular size 90 rotate retract. It is very easy to replace the original plastic trunnion. Open the housing, take away the plastic trunnion with the original strut wire, place it to the retract then reassemble it.
For some retrcts which included plastic scale looking wheel strut, like FMS F4U, P40, F6F, it is a bit of tricky but possible. You can not use the upgrade strut wire and side pin, because the plastic scale looking wheel strut is unable transfer. Thus you need to use the original strut wire.
In the picture below, you can see the side pin is not use screw thread, you need to pull it out form the strut wire first.
After remove the original side pin. Fix a collar before insert it to the metal trunnion. Afterward, insert the side pin back to the wheel strut.
The collar is very important, it is act as a stopper to avoid damage the retract unit when landing.