f-body suspension...(4th gen ls1)

I just figured I’d throw this out there if anyone needs it! :slight_smile: I wrote it up a while ago and it is on my website.


This is a real basic how-to that I am writing as I’m sitting at my desk, so it’s all based on memory. I do not recommend lowering springs if you aren’t going to upgrade the shocks as well…it will ride horrible and wear out the stock shocks super fast. I personally went with an eibach prokit for an inch and a half drop, and bilstein HD shocks - which are very affordable but perform well. You may need to modify this how-to depending on if you are just replacing springs, or just shocks, or what have you.


You will need:

a basic tool set with sockets, deep sockets, etc. I don’t remember all the sizes specifically but I know you’ll need a 13mm, 14mm, 15mm, 18mm, 21mm sockets, torx bits 40-50, 15mm deep socket. Gear wrenches are handy for swaybar endlinks. Jack, jackstands, spring compressor, channel locks, needlenose pliers, a ball peen hammer, etc.

  1. Jack the car up on all four corners. The wheels should be at least two to three inches off the ground. Support with jackstands on the frame rails, be very careful where you put the jackstands as something may look sturdy but it isn’t.

  2. Take off the wheels, all four. I like to start with the front suspension since it takes a bit more time. Starting with the left front…First you must remove the stock assembly from the car. When I say assembly, I mean the whole shock/spring macpherson setup. Begin by undoing the sway bar endlinks completely. Set the hardware aside (the bottom half of the swaybar endlink may or may not come out, its okay if it stays).

  3. Next remove the two bolts/nuts that hold the strut onto the lower control arm.

  4. Take the cotter pin out of the castle nut that holds the ball joint together. Once the cotter pin is out, loosen the castle nut with a 15 mm deep socket or wrench. Once the nut is completely off, hit the bottom half of the suspension with a hammer until it slides off the bottom of the ball joint. It may come flying off so watch yourself.

  5. Once the lower half of the suspension is loose from the balljoint, it may stress the brake line some. You may want to put a jackstand under one of the wheel studs to support it. Next, pop the hood and remove the master cylinder, which is held on with two 15mm nuts. Pull the master cylinder towards you, off the studs (you won’t hurt the ABS lines) and position it on top of the plastic cowl so it is out of the way. You need to access the four bolts/nuts underneath it. Two are large torx bolts, the other are 15mm nuts. Loosen them all the way and set them aside.

  6. The assembly is now loose. On the floor now, maneuver the assembly out from the lower control arm. Once its off, you can remove that top arm that sits on the assembly.

  7. Now comes the fun part, compressing the springs. There are many different ways of doing this. I personally used a widowmaker, which is two tools that clamp down on either side of the spring. Compress the spring until it is no longer touching the upper strut mount. Now loosen the arbor nut, I think its 18mm. Once that comes off, then does the upper strut mount, then the spring. Under the spring is a perch and a little isolater. You will need to remove these and put them on your new strut. If they don’t come off easily, tap them lightly with a hammer until they move.

  8. Place the perch onto the new strut. Then use your tool to compress the new spring, set it onto the perch, and then follow up with the upper strut mount and arbor nut. You’ve got to set it up exactly the way it was when you took it off the car - it only lines up one way. It’s hard to explain without seeing it. Once its set up correctly and the arbor nut is tight, loosen the spring compressor. Be careful.

  9. The assembly is now ready for the car, so reinstall it going backwards on the prior steps. Repeat for the other side. The passenger side of the car you do not have to remove a master cylinder or anything fancy, the bolts are much more accessible except for a couple pesky A/C lines.

  10. The rear is VERY simple. Support the rear end with a jack towards the front of the housing, so that it is putting pressure on the rear end and holding it up.

  11. Loosen the sway bar end links a couple inches. Don’t take the nut all the way off, just loosen them so that the rear will be able to drop down some. If you have a car that has been up north there’s a good possibility these endlinks are frozen with rust. If so, just hack them off with an angle grinder - a new endlink is available from Advance Auto Parts for $6.00 each.

  12. Remove the shock from the rear end, it is a 21 mm nut. Very tight. Get a good grip, don’t let your ratchet slip and smack your chin on the brake rotor like I did. Hey, if you don’t bleed it’s not a good install, right? Push the shock out of the rear end.

  13. Do the other side at the same time. With the rear, you’ve got to do both sides so it will drop down evenly. When the shocks are out of the rear and the swaybar endlinks are loosened, let the jack down a few inches. The whole rear end will come down, and now you can reach inside and slip the springs right out. There is a heavy rubber isolator on top, don’t forget to install that on your new spring. If you desire another half inch drop, you can remove the isolator and put 5/8ths heater hose on the top of the coil. Set the new springs on the rear end.

  14. From the top of the car, remove the child seat loop things from the trunk. Fold the rear seats forward. Remove the striker things that the rear seats latch onto as well. Both are large torx bits. Then remove the side trunk panels and pull up all the carpet as far back as you can. You will see two small foam pads on either side. They are not held in by anything so pull them out and underneath you will see the top of the shock. It’s held on with a 15mm nut. The piston may spin when you turn the nut, so you may need channel locks to hold it still while you break the nut free.

  15. When its all loosened, the shock will fall to the ground. Have a friend pass the new one up to you, tighten it down.

  16. Since you already put the springs in, gently pump up the jack, raising the rear back into place. You need to make sure that the rear springs go into the guides up in the wheel well - you’ll see what I mean when you take it apart. Pump up the jack til the rear end is in place, then reattatch the shock to the rear end using the 21mm nut.

  17. Now tighten the swaybar endlinks.

  18. Put all the wheels on the car, lower to the ground, and re-tighten everything again so you didn’t miss anything. Reinstall the carpet/hardware in the hatch.

  19. Test drive, make sure it’s all good.

  20. Get an alignment!! This is very critical. Even lowering the car a minimal amount can throw off your alignment specs. Better to spend $40.00 on it now then a grand on tires 5,000 miles down the road because you slacked off.