A strut brace is a simple but effective device that can make your car feel more stable and precise during cornering. When a vehicle is driven around corners, the forces that act on the chassis and suspension can cause these areas of the car to flex and move around, particularly where the upper part of the shocks mount to the chassis. A strut brace is a rigid piece of metal that is bolted to the opposing shock towers and that reduces the flexing by bracing the shock towers against each other. There are front and rear strut braces.
Open the rear boot if the vehicle is a sedan or the hatch area if it is a hatchback. On some vehicles you may need to access the upper strut mounts by folding down the seats and going through the rear seat area. Consult the directions that came with the strut brace you are installing.
Locate the nuts that fasten the upper part of the shocks to the chassis. There will usually be three nuts. There may be boot or interior trim that needs to be removed in order for the nuts to be accessed. It may also help to have a shop manual for your particular car that illustrates where the shocks mount at the top side.
Remove the nuts that are fastened to the studs that protrude out of the sheet metal. The studs are attached to the tops of the shock. Set the nuts aside somewhere safe where they won't be lost or misplaced.
Place the strut brace onto the studs, sliding the studs through the corresponding holes that are drilled in the strut brace. Ensure that the strut brace seats fully against the chassis where the studs protrude. Reinstall the nuts onto the studs and tighten them firmly.
Replace any trim, speaker brackets or anything that was removed to access the upper shock mounts. You may need to cut small holes in carpet trim pieces to allow the trim to fit around the strut brace.