Thanks to Fast91SE-R and floridasr20s.com for permission to mirror this writeup!
Items needed: Coilover springs, duct tape, grinder, various sockets 8, 12, 14, and 17mm, spring compressors (if removing stock springs), jack stands.
This will be a write up on how to install Ground Control Coilovers on a B13 Sentra. The front install notes could be used for B14 vehicles, but the rear suspension is different.
Front
Step 1: Jack up both sides of the car, and put it on jack stands. This will make it easier to remove the strut from the hub assembly. Next remove the wheels.
Step 2: Remove the 12mm nuts that hold the strut into the strut tower (3 nuts on each strut). If you are still using stock springs, try to remove the top shaft nut (usually 17mm) first, this way it lets the spring decompress, and you wont have to use spring compressors. You may have to use the 8mm wrench to hold the top of the shaft so it wont spin, then you will need to use a 17mm wrench. If you want to play it safe, go ahead and rent some spring compressors.
Step 3: Next remove the 2 17mm nuts and bolts that hold the strut to the hub assembly. Remove the strut/spring and take the spring off.
Step 4: In order to fit the Ground Control sleeve over the strut body, you will need to grind down the strut cap that sits right on top of the strut body. You will need a grinder for this, or if you're feeling lazy, knock it off with a hammer. This way "may" leak, so do what you feel is best.
Step 5: Once you grinded the cap enough to fit the sleeve over, you will notice it moves a lot, and does not stay in place. This is where the duct tape method comes in. There are other ways, but this is a simple way that usually works well. Have someone hold the roll of duct tape while you spin the strut around and wrap some tape around the strut body. Keep checking to see if the sleeve will fit over snug then go ahead and put it on.
Step 6: put the spring, collar and bumpstops on, and then the strut hat, you do not need to add the top spring seat. Finally tighten the top shaft nut, and install the strut/spring again. Next put the wheels on and bring the car down.
Rear
Step 7: Jack up the back of the car, once again, do both sides at the same time, it will be easier to remove the strut/sway bar.
Step 8: Climb in the back of the car and remove the seat, and the rear deck panel. This will give you access to the 12mm bolts do drop the struts.
Step 9: Once again, remove the 17mm nuts and bolts, and also the 14mm nut that connects the sway bar to the strut. Wiggle the strut out, and repeat steps 4-6.
Step 10: Once you get the car back on the ground, jack up each side to adjust the height. The best way to see if the car sits even is to use a measuring tape, and measure from the ground to the fender just above the wheel. Make sure you are on level ground to get an accurate measurement. Once you are done, tighten the collars, drop the car, and go on the twisties
The original writeup, with images, is located here.
