Lucius11

Hey friends, new here!
'94 4runner 4wd IFS

I'm finishing up rebuilding the front end suspension/steering, all stock besides 285/70/17 tires.

I'm doing an alignment myself in a couple days. I have researched plenty and messed around with the cams when I replaced the control arm bushings so I do understand how the cams work. Please don't suggest going to a shop, the nearest is over 30 miles away and I want to learn this myself first.

After setting ride height with the torsion bars, I then set caster and camber, then toe. Here is where I am confused and find conflicting info(all the write-ups I found are missing photos as well).

One document states to max out rear cam and adjust front cam out until wheel is near vertical, then you can adjust both cams equally for fine adjustments of camber. Another documents states to cam out rear 30 degrees, then cam out front 45, then adjust equally for camber. Another states to set rear cam out a couple marks more than front, then adjust cams out equally for camber. These are all different instructions!

can someone help me with clear instructions for the first steps of setting caster then camber?

I'm thinking the rearward side of the control arm should be out towards the wheel more than the front to set proper caster, then camber can be set by adjusting cams equally. If this is true, should I start by maxing out the rear cam all the way towards the wheel, or should it start less than max?

scope103

How do you plan to measure caster (and Steering Axis Inclination)? I've never done it myself, but I understand it's done by measuring camber at two different (measured) wheel angles, and a formula is used to compute Caster. Then the FSM has a pretty detailed description of how to correct both Caster and Camber. http://web.archive.org/web/201102060...axle/2-4wd.pdf (Me, I prefer the FSM over any writeup, particularly the conflicting ones.)

The methods you describe sound like "I don't know how to measure caster, so I'm just going to guess and then set camber." Which means you can follow any of the three you summarized, because they will all reach the wrong result.

I'm confident there is a way to do what you're trying to do without all the gadgets that a "real" alignment rig needs. It will just take a little longer. So I'm really interested in hearing how you work out all the measurements.

Lucius11

I'm not planning on measuring caster exactly. From what I understand as long as you maintain positive caster (rearward side of LCA out towards wheel more than front) then it should be within spec as long as camber and toe are then set properly and caster is relatively mirrored on both wheels.

scope103

If what you describe would work, then you'd never need an alignment. You'd just set the cams to the factory marks and everything would be correct.

But we DO need alignments, because wear on the front end components means you can't just center the cams and even up the tie rods for correct alignment. For instance, you have no idea if caster would be relatively mirrored if you don't measure it. Do you think that any of the three guess-and-by-golly techniques you found would be "correct"? All of them?

It's your truck, so you can align (or not) it however you want. But if you want to try a home-shop alignment, here's the derivation of the formula used to compute caster: https://www.scribd.com/document/3237...surement-1-pdf

How do you intend to measure camber? Not hard to do, but your solution might be more clever than mine.

Let us know what you come up with.

Lucius11

every document I've read on people who seem to know what they're doing say that measuring caster to perfect degree is not so important on these trucks as long as it's positive and mirrored on both wheels.

For example, these aren't correct numbers just an example ... on both sides I could cam out the rears let's say 5 marks and the fronts 3 marks. This would set the caster in the positive. Then for camber, let's say I cam out the rear 2 marks and the front 2 marks to adjust camber but maintain positive caster. Then set toe, then recheck, readjust...

for camber ill use either a carpenters square and measure off the rim or use a plumb bob draped over the wheel to set 0 degrees camber. And toe I'll run a string from the front wheels to the rear.

scope103

And yet you found what they said to be confusing, contradictory, and at odds with the Factory Service Manual. So you came to YotaTech searching for clear instructions.
That might work if somehow you KNEW that setting the cams to 0 on both sides meant that caster was exactly 1°52' on both sides. Then moving the cam 5 marks would change the caster by about 1° (now out of spec) but at least in the direction you wanted. But you DON'T know this. That's why we do alignments. For all you know, on one side correct caster is 5 marks cam-in (so setting to 5 marks out puts you 2°+ out of spec), and the other side is right on the money with 5 marks cam-out. At a minimum, there is no reason to think that you're mirroring caster just because you have the same cam settings on both sides.

Having out-of-spec toe or camber will produce (among other things) uneven tire wear, but having out-of-spec caster should show up mostly as poor handling. So there's some support for the idea that caster isn't as important as camber and toe. And, yeah, measuring those two is easier, so if you plan to get a shop alignment "someday," checking toe and camber in your garage is a good idea.

On my truck, the tread (distance between tires left/right) is not the same in the front and rear. So running a string from the rear tire will introduce some (probably small) error in toe. You might want to measure yours to be sure. And if you're going to go the trouble of measuring the distance from one rim to the other, you might just measure the front and back edge of the front wheel, which will measure toe directly.

The spec on camber depends on your model, but for most is very close to 0°40' +/-45' . So 0° camber is right on the edge of spec, as long as don't go more than 0°05' past 0. (0°05' is about a 1/32" difference from the top to the bottom of the rim; how big around is your string?)

As I said: your truck, do what you think best. But keep an eye on tire wear.

wyoming9

iTrader: (1)

I can see his point the whole Front end is brand new !!!

Correct ??

The only thing you will need to account for is poor fixtures when the frame was built

Then maybe you have built your own frame so all your attachment points are perfect is this correct ??

Might be they don`t drive yet !!

Then 30 miles is so far to drive might take the better part of a day how I drive.

akwheeler

I'm an old pro at alignments and I can tell you that you will not be doing yourself any favors. there is nothing perfect about the frame and mounting points on a 20 plus year old truck. Even if you are super careful about trying to make both sides match they won't, your truck will likely pull and tires will wear. Every adjustment you make will change the other settings slightly. swivel plates and an alignment machine are the only way to know for sure. your best bet is to set the toe with a tape measure (very slight toe in) and take it to a shop with the right equipment. most charge less than $150 (not sure about your neighborhood) and they can be done in an hour if they jump right on it. they will give you a printout of before and after readings so you can see how far off you were. the other option is to mark the cam settings carefully before you tear it apart and put it back exactly where it was and hope for the best, FYI you should only torque the control arm bolts at ride height (full weight of the truck on the tires). If you tighten the bolts at full droop they will wear out prematurely.

Whatever you decide, good luck. If your tires wear out or it pulls hard to one side because you did it yourself you only have one person to blame. but if you pay for an alignment and it pulls or the steering wheel is cockeyed you can make them fix it. Just keep in mind that roads are built with a crown and vehicles should drift towards the ditch (slightly). Also Imperfections in tire radials can cause a "radial pull" so a tire rotation may make it drive better if they try to sell you new tires.

Lucius11

I get what you're saying scope and thanks for the replies.

here's a couple references I'm using
https://www.yotatech.com/forums/f116/aligned-my-own-truck-great-results-69089/

https://www.yotatech.com/forums/f116/driveway-alignment-write-up-163432/

maybe I should just take it to the shop but I need to get it aligned close enough so I can drive the 30 miles safely and without tire wear

Lucius11

Thanks for the replies. The lower control arm bushings and cam bolts were destroyed from the previous owner, along with most of the front end components, so I have no reference point from before I did the rebuild. I felt pretty confident from the research I did on alignments but you guys make me think I should just let a shop deal with it.

scope103

Inconsistent (possibly erroneous) posts on YotaTech? I am shocked, shocked I say!

I think you CAN do a good garage alignment, including caster, if you fab up a few simple tools and take a lot of time. Personally, I think wrapping string around a truck is just too imprecise, but others do it with some success. (The string method does add something if you have independent rear suspension, as you have to set the toe to match the thrust angle. The only way the thrust angle is non-zero on a solid rear axle is if you've been in quite an accident. In which case, all bets are off.)

For me, I think I'd go with setting the toe "close" (to zero) with a tape measure, then driving the 30 miles. It will take a while to do real tire damage, so long as you can keep it on the road.

Lucius11

Thanks again for the suggestions. I'll get the toe close enough and drive to the shop