Homeschooling, Computer Upgrades, Front Bushings, & Alignment
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It's been quite awhile since my last post. I've had quite a few things going on, and the polyurethane suspension upgrades took much longer than predicted.
My wife and I were discussing the virtual school program my children were enrolled in and decided that (1) they weren't being challenged enough, and (2) they were not able to move at their own pace. We've also been concerned that they were still in a government school and might still get a fair amount of indoctrination into all kinds of things we despise, whether it's an airhead culture, statism, socialism, or (worst of all) Keynesian economics. So, we made the switch back to true homeschooling.
"Barny the Barncat" one of the most important tools in my workshop. It just got upgraded because my kids are homeschooling. Makes perfect sense, right? Note blue "cantenna."
There was a flurry of purchasing activity and I found a way to buy my way into sharing Amazon Prime with some family members, which helped us get some of our stuff pretty quickly. Note that Amazon doesn't really care if your "houshold" members actually live in the same house! Along with these purchases, my daughter needed a new laptop (amazing machines can be purchased for a mere $350 right now!). There was a shift in computers around the house, and my wife's old machine wound up sitting in the corner in the basement. Right on cue, the machine I keep in the barn went Tango Uniform. The slightly newer machine came out of the basement, got the Lubuntu (Light Ubuntu) Linux distribution installed, and now gives me access to the Web while I'm working out there. I stream music from Shoutcast and Pandora, listen to podcasts, read online repair manuals, and look up parts and tools I need. The barn is a few hundred feet from the house, but in the photo you'll notice a little blue food can under the CPU pointing toward the wall (and the house beyond). This is my cantenna, which is a homemade high-gain WiFi antenna -- allowing access to my WiFi when I'm out there. Here's the site that taught me how to build one, if you are interested.
In my last post I discussed the process of installing polyurethane bushings in the Suburban's rear end. Don't underestimate the level of effort involved in these things! The handling was certainly upgraded by these efforts, but it wasn't a quick, easy job. Rather than bore you with too much detail, let me share a few tips that might be helpful with replacing bushings in the front end of this and similar front ends:
Removing torsion rod arms using the c-clamp from a bearing press tool.
Get the front end nice and high off the ground and support it securely with some jack stands. You'll spend lots of time under there, and it's nice if you aren't bruising your forehead too much! This provides more room to get under there with tools.
The very first parts removed should be the torsion rods. I removed the torsion rod adjustment bolts. Then, I used my Chinese bearing press tool's c-clamp to push the cams upwards just enough to remove the little rocker pieces that the bolts screw into. Then, I carefully released the pressure from the cams, completely unloading the torsion rods. Stay clear, in case the c-clamp pops off, because these things store lots of energy and could really hurt you. Then, I pushed the torsion rods forward, through the lower control arms (which drops the cams, so watch your head!), before pulling them out above the torsion rod cross-member.
I did the upper control arms first, supporting the lower ball joint with a floor jack and hanger-wiring the knuckle to the upper control arm, so that it wouldn't pull on the brake hose too much. I unclipped the ABS wires from the upper control arms, so that I could swing the arms outwards for easy access to press bushings in and out.
Heating the rubber bushings with a torch before pressing is highly recommended, as it debonds the rubber from the metal sleeves and shells, while softening the rubber--making them much easier to remove.
Check to see which shells and sleeves are included in your bushing set, because you may have to reuse some of the old ones. Not realizing this, I butchered some of mine in the process, and had to buy some cheap rubber bushings from O'Reilly's in order to replace some of them.
Inner shafts can be unbolted to allow the lower control arm pivot bolts to be removed. This is much easier than unbolting the differential assembly (ask how I know)!
On the lower control arms, I found out that the rear bolts point directly at the front shaft assemblies. It might not be a problem with a normal geometry, but my front differential assembly has been lowered 2" to make room for the diesel engine's oil pan (which still had to be modified). These can be unbolted and the inner shaft moved out of the way.
In some cases, rather than using the bearing press to push out the bushings I used some 1/2" threaded rod, some PVC pipe, nuts, and plates with holes drilled in them to push bushings in/out. If the process is too tough, apply more heat and experiment with other ways to get leverage.
Don't pretend that you'll be able to put things back in the same position and avoid an alignment. You will need an alignment when you are through!
Adjusting ride height, using a basic tape measure. I had to raise this side of the vehicle a fraction of an inch.
Eventually, I got everything back together and did my own alignment. I did it myself, because I wanted it done right. I've been extremely disappointed with the half-assed job that many alignment shops will do. With a few tools, some of them homemade, you can do this yourself.
First, one should park the vehicle on a flat, level surface. Bounce the front end up and down to ensure that the suspension is sitting at the right height. I found out the correct range for the Suburban's ride height by consulting an online manual, and chose to shoot for 6". For this vehicle, this is defined as the difference between the height of the center of the lower control arm's rear pivot bolt and the lowest corner of the knuckle. I used a tape measure to check these. This is adjusted by turning the adjustment bolts on the torsion rods. When one side is adjusted, bounce the vehicle and check that side again. Also, check the other side, as an adjustment on once side will likely affect both sides.
For the next step, you may need to put shims under your tires to get the vehicle level left-to-right. In the last place I lived, I used a length of tubing with water in it attached to jack stands as a type of level (ensure you get any water bubbles out of your column of water). I compared it to the rim height on both sides and played with shims on the floor to get the car perfectly level in the right-to-left direction. This is important, because you want accurate camber measurements, next. In my current workshop, one of the stalls has a near-perfect level floor.
Using the camber gauge to check the wheels' angle from vertical.
I have a camber gauge that is held up against the outside of the rim at the bead. This can measure the camber to within 1/8 of a degree. When adjusting the upper control arms, I only adjust the front or the rear of the upper control arm, choosing the direction that increases caster (and, hence, straight-line stability). If I'm moving the top of the tire inwards, for instance, I'll do this by moving the rear upper control arm inwards, which will swing the upper ball joint toward the vehicle's rear. If I need to move the top of the tire outwards, I'll move the forward control arm outwards, for the same effect. Some might claim that I could wind up with too much caster, but it's never been as critical as having the right camber angle.
My trammel bar--used to measure and adjust toe-in.
With ride height and camber set, I then adjust toe-in. The tool for this job is one I built years ago from a 2x4 with boards nailed to the ends. The ends should ideally be half the height of your tires. I use masking tape on the tops of the boards to give me a place to mark measured locations. I can apply a fresh strip of tape to each for each alignment session--eliminating the possibility of forgetting which marks I'm using.
This process involves pushing the vehicle forward and backwards--something that you won't and shouldn't do if your floor isn't level front-to-rear. Even if it is, you are dealing with a great deal of mass, and it's a good idea to put a 2x4 in place as a stop near the entrance to your garage to keep your vehicle from rolling away on you.
Using pins and the trammel bar to measure toe-in.
I start by rolling my vehicle as far to the vehicle's rear in the workspace as possible with the wheels pointed straight ahead. I then place the trammel bar behind the front tires. I push pins into the lugs of each front tire where they meet the trammel bar boards and make markings where they touch (you won't puncture the tires, if you stick to the lugs). Then, I push the vehicle forward until the pins are at the front of the tires and compare the distance between the pins with the markings I made earlier. On this vehicle, I calculated (basic trig) that the front of the tires should be 1/8" closer than the rear for proper toe-in. I adjusted the tie rod end sleeves using the OTC 7023 sleeve adjuster tool. This thing works much better for twisting old, rusted/frozen sleeves than a pair of channel locks! The hooks can grab the sleeve's gaps from different angles, and the handle slides back and forth -- allowing you to gain leverage, even in tight spaces.
OTC 7023--a must-have tool for adjusting tie rod ends.
Remember, however, that any changes you produce in measurement from the marks while adjusting are doubled. This is because if you are bringing the fronts of the tires closer to each other, you are widening the rears. So, if I measured 1/2" of toe-in and I want 1/8", I consider that the half-way point between the front and rear pin locations (the 1/4" point) would represent zero toe-in. I'll mark that halfway point, and adjust so that the pins are 1/16" inside of that halfway point. If the fronts are 1/16" inside of zero toe, the rears are 1/16" outward -- giving me 1/8" of toe-in. This is confusing and easy to screw up, so check your work when you think you have it! You wind up rolling the vehicle back and forth a few times, but the results are worth it.
Then, you have to take the vehicle for a ride on a straight road to see how far off the steering wheel center is. If the roads are crowned, I'd recommend using a straight piece of backroad where you can center the vehicle on the crown to take out that bias. If you use a highway, crown won't be as pronounced, but check both lanes. Sometimes the left lane is closer to level. Then, take the vehicle back to the garage and make incremental adjustments to the sleeves until the wheel is centered on your test-drives. On the Suburban I've noted that the outer tie rod ends have right-handed threads. Keeping this in mind if I shorten the linkage on one side 1/4 turn, I make sure to lengthen the other side 1/4 turn -- in order to keep my toe-in correct. When you have the wheel straight, check your toe-in again.
--Yes, you can pay somebody else to do it, but will they care enough to do it right?