Subframe Lockbolt install:

1.) Safety jack up your Subaru Impreza WRX/STi.

2.) Place jack stands in locations that will not inhibit rear subframe movement,

3.) Break all four of the subframe bolts loose, but do not remove the bolts. There are two bolts on each side of the subframe. The bolts will take a 17mm socket. Only use a 6 point sock. Note: Do not use a 12 point socket otherwise you might round off the subframe bolts.

4.) Once the bolts are loosed inspect the exposed threaded holes where your subframe lockbolts will go.

5.) Spray some lubricant like WD-40 into the threaded hole and use a bottle brush to loosen any dirt or rust that is built up in the hole.