A quick how-to for fitting lowering springs to a GTC/VXR. These cars are fitted with the same suspension set-up as the Insignia VXR known as the Hi-Per Strut

Tools required

Trolley jack
Axle stand
E20 socket
T30, T40, T50 torx
8mm, 18mm, 19mm, 21mm, 24mm, 32mm sockets, through socket is best for the strut upper mount fixing
Locking wheel nut key
18mm, 21mm spanner
Hub puller
Ratchet
Breaker bar
Soft face hammer
Torque wrench
Spring Compressors

You'll need the following new bolts and nuts

Qty 2 13217120 Hub nuts
Qty 4 11609282 Tie rod/Droplink nuts
Qty 2 13258478 Lower Control Arm Bolt
Qty 2 11516382 Lower Control Arm Nut
Qty 2 11589281 Shock Pinch Bolt (If changing Shock absorber)
Qty 2 11516078 Shock Pinch Bolt Nut (If changing Shock absorber)
Qty 4 11562022(321mm disc) 13331028(355mm disc) Caliper bracket bolts

Remove the wheel centre cap and hub nut cover.
Using a breaker bar and a 32mm socket loosen off the hub nut, it's easier to do it with the car still on the ground make sure handbrake is on and place in gear to help prevent the hub rotating.
Loosen off the wheel nuts.

Jack up the vehicle on the chassis box section


Support the vehicle under the front chassis rail so not to interfere with the lower control arm. Remove the wheel, you can then remove the trolley jack


Unclip the brake hose from these brackets


Remove the the electrical connector from the suspension leg, then disconnect the electrical connectors by twisting the black housing and pulling out the connectors


Undo the caliper to hub bolts using a E20 socket and remove the caliper complete and either support it with heavy duty wire or place it on the floor as not to stress the brake hose.


Remove the Disc screw T30 screw and remove the disc


Remove the hub nut with 32mm socket


Remove the drop link by using a 18mm socket/spanner and T40 socket. Using the trolley jack support the strut weight enough to allow the droplink to be removed from the strut


Using 18mm socket/spanner and 8mmspanner/socket remove the Tierod nut, then using a soft face hammer tap out the ball joint


Using 21mm socket and 21mm spanner remove the lower control arm bolt and nut, caution should be taken as when the bolt is fully removed the control arm will drop


Remove the outer most plastic clip holding the scuttle panel down. Then using a 24mm spanner and T50 socket loosen off the strut upper mount, it might help if you supported the strut with the trolley jack


Hi-per strut removed


Comparison between standard and lowering springs


Crack off the upper strut bearing nut using 24mm spanner and T50 socket. Using spring compressors compress the old spring to enable the removal of the upper strut bearing. Swap everything over and rebuild everything in reverse order of above using new bolts and nuts as listed above.

If your changing the shock remove the single pinch bolt and nut that holds the brake pipe/electrical connector bracket then slide the chock out from the rest of the strut

The torque settings are as follows

Shock pinch bolt/nut 70Nm (52 lbft)
Strut shaft nut 70Nm (52 lbft)
Upper strut mount nut 45Nm (33 lbft)
Lower control arm bolt/nut 115Nm (85lbft) then 120°-135°)
Tie rod nut 35Nm (26 lbft) then 30°
Hub nut 150Nm (111 lbft) loosen by 45° then retighten to 250Nm (185 lbft)
Drop link nut 65Nm (48 lbft)
Disc screw 9Nm (7 lbft)
Caliper bolts 150Nm (111 lbft) then 45-60°
Wheel nuts 140Nm (103 lb ft)

Front springs fitted


Hope this helps any other GTC/VXR owner. I'm happy to help out seeing as I've now completed it myself