How to Install Shocks/Struts and Lowering Springs
This install was done on ctimm_rs's 91 Sunbird GT at his dad's shop, Timm Automotive Repair in Roland, IA. I assisted with the install and took pics so that I could write up this how-to.
- New shocks and struts. Monroe Sensa-Trac's were used here (but they suck!)
- New springs. Eibachs were the choice here
- Air tools are almost a must have here. Almost every bolt will be seized on
- Spring compressor - necessary to get the spring on and off the strut (front only)
- Big pry bar and/or pickle fork, or 2 jaw puller.
- Other misc. wrenches, sockets and other crap
How To Do It
Measure your stock ride height just for fun, so you can see how far the springs actually drop your car.
Raise the front of the car. We had the luxury of having a hoist, but you probably won't be that lucky. Raise both sides and support it with jack stands. If you don't have an impact wrench, be sure to loosen the lugs on the front tires before you raise it off the ground. Once it is up in the air, you can remove the front tires.
If you have a camber gauge, get a reading from it to aid in getting the camber closely set upon reassembly. If you don't have a gauge, mark the relationship of the strut to the steering knuckle using a scribe to mark the outline of the strut onto the knuckle. If you aren't replacing the struts, you can also scribe around the bolt onto the strut. This will ensure you get everything lined back up correctly upon reassembly, so your camber won't be totally out of wack before you get the alignment.
Remove the 2 nuts holding the strut to the steering knuckle. You might want to spray them down with some penetrating oil first, to loosen em up, especially if you are using hand tools, as the nuts will most likely be seized. Once you get the nuts loose, back them off, but leave them attached to the end of the bolt for the time being.
Remove the cotter pin from the tie rod bolt using pliers or side cutters to slowly work it out, and remove the nut. Using a pry bar and/or a pickle fork, or better yet, a 2 jaw puller, separate the tie rod from the strut arm. Be careful not to tear the boot.
Hammer out the steering knuckle bolts that you already loosened the nut on. These bolts are splined, so they will not turn, so don't try to do so. You might want to leave the nut on the end of the bolts so that you have a wider area to hammer on, and so you don't mushroom the end of the bolt. Remove the nuts when you can't pound them out any further, then continue to pound them out the rest of the way. It may be necessary to hammer in a smaller bolt to force them out, once the end becomes flush with the knuckle, if you are unable to complete the removal by pulling on the bolt head. Be careful that you do not over extend the CV joint, once the assembly drops free of the strut. You may want to secure it with wire so it does not hang down too far and break something. You could also damage the brake if the knuckle falls down too far.
Now come up under the hood and remove the 3 bolts holding the strut mount into the tower. Once you get these 3 out, the strut should be free and you can wrestle it out of the car.
You may or may not need to do the following step. If you did not buy a new mount and boot for your shocks, you are going to have to remove them from the old unit to use with the new. This requires the use of a spring compressor. There is no other way to separate the shock from the spring, so don't even try. People have been killed by springs shooting accros a garage. These things can put a hole in a concrete wall. They are under that much pressure. You should be able to rent a spring compressor from the parts store for the afternoon. We were lucky enough to have this wall mounted unit
Using the compressor, compress the spring until there is slack between the spring and the mount. Now you can remove the upper retaining nut. An allen wrench should fit into the center to prevent the stud from moving, while you remove the nut with a box end wrench. If it is seized, try a little penetrating oil. Once you get the nut off, the strut can be separated from the spring, and the spring can be carefully uncompressed
Install the new strut inside the spring using the spring compressor. Pay attention to how the old unit came apart, so you get he new unit assembled correctly. The flat side of the mount should be aligned with the steering knuckle mounting flange on the strut. Be sure to index the springs on the strut and mount correctly. There should be a mark on the mounts that indicate where the end of the spring should go. If your old mounts are junk, you should replace them, but if they are alright, it is ok to reuse them. Once you get everything seated properly, install the top nut and uncompress the spring.
Time to throw that beast back in the car. Maneuver the strut up into the tower and loosely install the 3 nuts at the top to hold it in place.
Align the arm on the strut with the tie rod, and line up the steering knuckle with the bottom of the strut. Reinstall the bolts through the steering knuckle, and the bolt on the tie rod end. Be sure that the nut lines up with the hole in the bolt, so that you can slide a new cotter pin through. It is best to use a new cotter, because the old one probably got all bent up when removing it. Before you tighten down the nuts on the steering knuckle (35 ft/lbs), realign the strut to the marks you made, or use the camber gauge to reset everything to the correct angle. Now, tighten down those 2 bolts (140 ft/lbs), and make sure the camber is still reasonable accurate.
Make sure all the bolts are good and tightened down. Just don't over tighten the 3 bolts at the top of the mount, or you might break off one of the studs. One corner down! Now just do the same for the other side on the front. Reinstall the front wheels when you finish the other size and torque the lugs down to 100 ft/lbs
Time to move on to the rear. Raise the car by the frame, and support the frame on both sides with jackstands. Place a floor jack under the rear axle to raise the axle back up to the same position it was in when the car was on the ground. Soak down the bottom bolt on the shock with some penetrating oil to attempt to loosen it up. Hopefully you don't have the problems we did... ;)
Rachet on the bolt until the blind nut on the back comes loose. The blind nut has a long tab sticking out, so you can grab it with pliers while you remove the bolt and then pull it out. Hopefully the nut will come out of the hole as well. The drivers side bolt on Cory's car would not budge at all after the blind nut came off! After lot of prying and hammering, the head of the bolt had to be ground completely off, so an air hammer could be used to force the bolt through the hole. Hopefully you won't have such a problem!
Once you have the bolts on both sides out, lower the rear axle until there is enough clearance for the springs to drop out. The shock is the only thing that holds the spring in place, and since you removed the bottom bolt, the springs are ready to come out. The springs will probably fall out as you lower the axle. Don't let the axle drop down too far as you can snap your brake lines!
If you did not buy new mounts, you will need to remove the old mount off the top of the shock. I recommend getting new mounts, as the mounts we had were seized on so bad they wouldn't come off for anything! Ended up putting the old shocks back on until new mounts could be ordered.
Now we can put in the new springs. Put the insulator and compression bumper back into position on the spring so they are ready to go back into the car. Be sure the springs are indexed correctly on the top mount (pay attention to how they were removed). The spring reinstallation can be a bit tricky because you will have to get both sides seated correctly. This requires raising the axle just enough to hold them in place, but not so high that you can't maneuver them. You will probably need an assistant for this part. Once you get them seated properly, raise the axle enough to hold them on place, but not so high that you can't get the new shocks in.
Install the new shocks the reverse of removal. Install the top bolts first. You will need a hand for this, since you will have to hold the shock from underneath, while it is bolted from the trunk. Once you have the top secured, install the bolt and blind nut at the bottom. Hold onto the tab on the blind nut with pliers while you tighten the bolt. Avoid holding it by hand, especially if using an impact wrench, as it could move and pinch your fingers! Tighten everything down good (lower bolt 35 ft/lbs, top bolt 13 ft/lbs), lower the jack under the axle, and lower the car back down all the way.
Now it is time to see how much these new springs really dropped the car. The Sunbird got dropped 1 5/8" up front, and a half inch in the back, for a final ride height of 25 1/4" to the top of the fender up front, and 25 3/4" in the rear. The rear on the V6 J-bodies always sags with the stock springs, which is why the rear drop wasn't as much.
Thats it! Congratulate yourself on a job well done!. You now need to take your car in for a professional alignment before you do too much driving. If you don't get it aligned, the camber may be way off, and your tires will wear uneven, and you won't get as good of handling and ride quality. The ride quality in the Sunbird definitely improved. No more nose dives upon breaking, and minimal leaning in the turns. Not to mention it just plain looks better!