May I make a different suggestion? Look for a nearby community college with an Automotive program where they will allow you to take just the Suspension and Alignment course. You'll learn how to remove the spring, and you'll find out you have the wrong kind of spring compressor. What you have is for the lighter springs that go around struts. Compressors for your type of spring come as complete sets of plates and a fat threaded rod. You might be able to rent that set from an auto parts store that rents or borrows tools. Few mechanics own their own set because of the cost. Using that type of compressor requires the shock absorber to be removed.
Wall-mounted strut spring compressors are relatively safe but anything that is used on the floor is a toy at best and very dangerous. I saw a spring pop out and take out an overhead 8-foot florescent light fixture, and I had one pop out that I had to chase through the shop, out the garage door and down the hill!
You're smart to be worried about safety but I have a different method of removing springs that is a lot safer than what is spelled out in the service manuals. I figured this out in the '80s when we replaced lots of front springs on General Motors cars. Instead of disconnecting the lower ball joint, risking the control arm sliding off the jack and hitting you, and having to pry the spring out, then chase it across the shop, support the pivot side of the control arm, remove the two pivot bolts, then slowly let the arm come down. I did that with a post jack and the car on a hoist. You can do that with a floor jack. Once the control arm is down a few inches, the spring will no longer be compressed. If you have the room, you don't even have to remove the wheel or the upper shock absorber bolts. No spring compressor is needed. You just set the new spring in place, then pump it up with the jack and stuff the bolts back in.
Some things you should be aware of are first to be sure to clean out the pocket the spring sits in. Small rocks in there can cause crunching noises. You must watch the orientation so the end of the coil sits in the end of the groove in the control arm. If one is turned incorrectly, the ride height won't be the same on both sides. It's also very important that the pivot bolts not be tightened until the car is sitting at rest off any jacks. I always drive the car a few blocks, then run it up on a drive-on hoist to finish tightening the bolts. If you tighten them when the car is up on jack stands, the suspension will be drooping and you'll clamp the rubber bushing in that position. When you lower the car down you'll have those bushings in a permanent twist. That will lead to very early failure.
That said, you will also learn why no mechanic will ever do what you are trying to do. We spend a lot of time and money trying to restore cars to their correct ride height for many reasons. When you raise or lower a vehicle, you change the front-to-rear brake balance, you affect the changes the alignment angles go through as the car goes up and down over bumps in the road, and you greatly affect the handling and comfort for the worse. You might be able to readjust the alignment angles for a car sitting still on the hoist but those angles were calculated and fine tuned by the manufacturer related to the suspension geometry which you will be changing. Even if you get the alignment numbers close to what was specified, you ARE going to have increased tire wear and reduced braking. Lawyers and insurance investigators love to find stuff like that. Even if the other guy runs the red light and you hit him, you can be guaranteed you'll be involved in a lawsuit because the other guy's insurance company will try to reduce their percentage of liability. A mediocre lawyer will convince the jury that you were partly at fault because you were less able to avoid the crash. There will be absolutely no argument that you made your car better or safer. All the jury has to hear is you modified it, and you're partly at fault.
No one in my program, let alone my Suspension and Alignment class was allowed to put lift kits in trucks or to lower cars, and no one wanted to once they understood how the steering, braking, handling, and tire wear were designed to work together. Also, most shops will not work on your car for anything once they see the modifications because they're worried about being a party to any future lawsuits, even for things that would seem to be totally unrelated. The smartest thing you can do is leave the ride height where it's supposed to be.
Wednesday, May 30th, 2012 AT 10:25 PM