To Convert the F109 to CRC rear side spring I did the following
You will need
2 x m3 12mm grub screws
2 x 3x3 m3 grub screws
2 x
1 x CAL-1287 Calandra CRC Metal Spring Holders
1 x CAL-1280 Rear Side Spring Set
(If you do not use the below items you will need longer m3 grub screws of about 16/18mm long)
1 x CAL-1256 Chrome Pivot Balls (2)
2 x af cs screws 4-40 x ¼
1st step is remove the rear block with the side springs in, remove the rear top deck mounts and fit shorter pins or cut them down, these can be glued in place or a 2.5mm hole drilled and a 3x3 grub screw threaded in as picture to secure the pin.the pin needs to be mounted so it does not go into the hole where the grub screw was that held the pin in place originally
Next take the CRC spring mount and wind in the long m3 grub screw, this will be tight as the threads are wrong, I tightened mine as tight as possible and fit the springs.
Now screw the spring mount in from the bottom side so the spring goes into the recess.
I fitted the CRC ball as it allows the spring to move freely instead of twisting the spring on the chassis plate, the af screw fits perfectly in the chassis countersink.
Reassemble and adjust tweak from top near body rear posts.
