2WD C10 Modern/Performance Alignments

[gringoloco]

Nice caster numbers- I could only get ~3*... Interested to see what tomorrow's alignment brings. Any binding issues with the upper ball joints? This is cool

[BMERDOC]

Originally Posted by gringoloco

Nice caster numbers- I could only get ~3*... Interested to see what tomorrow's alignment brings. Any binding issues with the upper ball joints? This is cool

What were your mods at 3(we need the info)? If you look back my stock alignment I was just barely over three degrees. Look at the pics the swap
picks you can see how the spindle was REALLY tilted back but the swapped arm nicely tilted back so as to make a nice centerline through the bj (draw a line through the zerk fitting and down the spindle). Its the lower I'm worried about. The angle looks ok now but I'm concerned bout cycling. BTW, the lower arm is flat and the centerlink/tirerods are nice and flat so I'm not really concerned with bumpsteer

[BMERDOC]

Originally Posted by gringoloco

Any binding issues with the upper ball joints?

Having reviewed the pics the zerk fitting/spindle center line isnt as as close as I thought. Note the tire is off and the suspension in dangling. I'll have to look closer at ride height.

[gringoloco]

3" drop spindles/3" drop springs. Ended up with 2.7*, I think. Been a while and I don't have the print out. I told the tech to hook me up with as much caster as he could muster and that's where we landed...

I've seen people flip the uppers upside-down; don't know if that would help with angles.

[BMERDOC]

Ok. I had time to tinker so after swapping the upper control arms side to side. Here are the results. I think this debunks the thought that the uppers can be swapped. Yes, the caster is excessive and could be brought to 8 or 9 degrees by adding about 9/16" to 5/8" thick shims to the rear but the camber is already positive and can't be remedied. Time to swap the uppers back and notch the lowers....

[SCOTI]

Originally Posted by BMERDOC

Ok. I had time to tinker so after swapping the upper control arms side to side. Here are the results. I think this debunks the thought that the uppers can be swapped. Yes, the caster is excessive and could be brought to 8 or 9 degrees by adding about 9/16" to 5/8" thick shims to the rear but the camber is already positive and can't be remedied. Time to swap the uppers back and notch the lowers....

Interesting.... I wonder what the results will be w/the lowers shifted forward. How much do you plan to move them for the testing?

Also, possible cures for the upper arm cross-flip issue: narrow the upper arms 1" or maybe some of those Moog 'problem-solver' off-set upper a-arm shafts??

[BMERDOC]

I will have to check but I think I read 3/4" forward. Not sure if thats center to center or from the leading edge. I'd love to be a little more scientific but time restraints....Its late. I'm gonna do some research tomorrow.

[oldgold70c10]

Well I had my truck re-aligned today. Final camber was right around -0.5 degrees on each side, caster is +4.39 & +4.5 degrees. That was as close as he could get. Removed all but 1 shim on the driver's side, still have a stack of shims under 1 bolt on the passenger side.

[BMERDOC]

Originally Posted by oldgold70c10

Well I had my truck re-aligned today. Final camber was right around -0.5 degrees on each side, caster is +4.39 & +4.5 degrees. That was as close as he could get. Removed all but 1 shim on the driver's side, still have a stack of shims under 1 bolt on the passenger side.

Awesome!! So? How does it drive? Did he question your desire to throw away the old specs?

[BMERDOC]

I think I'm about to say something really good about toe but I cant get my thoughts straight. I've written a post four times now and erased them all. I need to sort my thoughts. Im thinking maybe I should start a Word file and cut and paste once i feel its right. Its nothing genius just solid thought from an over active mind.

[Spla'nin]

Originally Posted by BMERDOC

Ok. I had time to tinker so after swapping the upper control arms side to side. Here are the results. I think this debunks the thought that the uppers can be swapped. Yes, the caster is excessive and could be brought to 8 or 9 degrees by adding about 9/16" to 5/8" thick shims to the rear but the camber is already positive and can't be remedied. Time to swap the uppers back and notch the lowers....

Nick, Thanks again for your work to check this out and your well documented results, ... the additional benefit that Rob mentioned in the "make it handle" thread by moving the LCA forward, is the weight % shift to the rear...

[0bad0boy7]

Originally Posted by BMERDOC

Ok. I had time to tinker so after swapping the upper control arms side to side. Here are the results. I think this debunks the thought that the uppers can be swapped. Yes, the caster is excessive and could be brought to 8 or 9 degrees by adding about 9/16" to 5/8" thick shims to the rear but the camber is already positive and can't be remedied. Time to swap the uppers back and notch the lowers....

This quote is from post #74

It looks like the swapping the uppers gave you a gain of approximately 10°. I could really use a 10° increase of caster since I am at -4° on both sides now. I just replaced all the suspension parts and perhaps the previous owners of the truck reversed the arms. Thanks for the detailed posting on this thread.

[robnolimit]

doc, I moved mine, on our JT build, 1" forward, and 1/8" out. This is from CL of the OE socket, to CL of the new socket. Keep up the good work.

[BMERDOC]

Thanks Rob! I will assume that you got 8 or 9 degrees of caster with a 1" movement?

[robnolimit]

yes, without much mis-match in the shims

[hairlesshobo]

This thread is awesome. Nick, I am very appreciative if the time that you are putting into this for all of us!!!

So I have a shiny new caster camber gauge on the way and icsnt wait to take a whack at my own alignment. My concern is that ive read that the wheels must be turned exactly 20* in each direction when performing an alignment. I know that turnplates can be purchased but they are well out of my price range. I read a few pages back that a couple pieces of tile and greese can be used. Can you go into this in more detail? Is there a better way to measure this? (My idea involves fabricating some metal plates to use as a guide, but if there is a string, tape measure, or any other method that works I'd love to hear about it.

Thanks in advance everybody.

[Mike_82_Shortbox]

@hairlesshobo

I appreciate your gusto! But you know, a good alignment is pretty cheap, about $60.

Anyway, generally, without knowing anything about your guage, you also have to lock the brakes to do a caster sweep, and that means all 4 brakes, not just the e-brake. So you need to jimmy-rig something to jam the brake pedal, or get the special tool to do it. It's just a bar with a pad and a stop. It works just like the thing that holds the screen door open on your front door. Just open the door as far as you want, set the little metal thingy, and it stays.

When I first bought my truck I aligned it just by feel. It wasn't great, but it drove OK. I think you'll have better results using some tools on it, but you'll never get it as fine-tuned as a guy using a Black Widow alignment machine.

Good luck, and have fun.

[Mike_82_Shortbox]

Nick,

Thanks for the lengthy discourse on your alignment specs and theories. It got me on the right track for my 82 Chevy Shortbox. I recently replaced the upper ball joints, idler arm, pitman arm, and all the tie rod ends, but had to have a shop do the lower ball joints, since I had no press and couldn't even get the old joint tapers to release. That shop also did an alignment.

The truck drove worse than ever, and I mean ever! So I started asking questions, and I found a shop where the guys had fixed a lot of Chevy frames, where they crack at the steering box, and who said that they regularly put 8° of caster on big 4-wheel drive pickups, whereafter they drive like a dream.

I tried to take the truck back to the original shop, but my appointment time came and they blew me off, so I demanded a refund, and took the truck to Les Schwab, where they have the same alignment machine as in your pictures. Sweet!

My thrust angle started out (left) at -.35°, and I can't do anything about that.

Eight degrees sounded a little extreme for me, but I liked your idea of a lot of caster.
I requested 3.5° of caster on the right, and 3.25° on the left, and got 3.7° right and 3.3° left. Pretty good, and still within a half-degree side to side.

I liked your argument about camber, but the book and the alignment tech said slightly positive, and exactly equal side to side, so I ended up with .5° positive camber on both wheels. OK.

The tech said it was the difference in caster that compensates for road crown pull, but I still like the idea of slightly less camber on the left.

Finally, the book calls for .13° to .25° toe-in (.26° to .50° total), and using your midrange method, that puts each wheel at .18° with .36° total toe-in. I ended up at .20° for a total toe of .40°, which is right about the midrange average. OK.

The bottom line? The truck drives like brand new now, and if I feel like I want to tweak something in the future, Les Schwab said they would happily do it, and not turn me away when I set an appointment. The alignment cost me $56 there.

So anyway, you gave me a big push in the right direction, and if you're still out there, thanks.

Mike

[BMERDOC]

Thanks for the feedback Mike! It is good to see this info really working for people! The original factory specs are horrible at best. A truck drives like a truck for a reason but a better alignment can improve the way it drives. It was my intent to show you guys the factory specs and how they could be modified for a better driving truck and what happens to the alignment as the truck is modified. I wanted you guys to be able to read an alignment sheet and understand what it all means so that you can make your own educated judgement on how to modiy your trucks specs while at the alignment shop. I can't wait to see more feedback from others!

As far as your trucks alignment goes, it makes me courious to see how far out the Thrust Angle has to be before the truck is "dog tracking" so bad that you can visually see it. I'm starting to think that as results come in from other guys we will see some rather large numbers. I would venture to say at this point that -.35 might not be so bad.

[Mike_82_Shortbox]

Nick,

My truck was a rebuilder, put together by a couple of guys who did a repectable job; there really aren't any rattles or squeaks to speak of... But the truck was hit at the front left frame rail, and I think that unsquared it a little, giving me the left thrust angle. Push the left rail back, and it turns the rear axle to the left.

The alignment guy said he has seen these old Chevy trucks with angles of plus or minus .45°, and it didn't hurt the alignment or make the truck pull, or make it hard to center the steering wheel. I would imagine that to actually be visible following a rig, it would have to be off by 5 degrees or more.

Anyway, I've driven the truck for a couple of days now, and it corners better than ever, drives straighter and truer, and the wheel unwinds from turns in a predictable and positive manner.

So I decided to spend a thousand bucks on new wheels and tires!

Thanks again!

Mike

[BMERDOC]

Originally Posted by hairlesshobo

I am thrilled to hear that. So I assume my idea for checking if the axle is straight would work then?

The method you are using is one of the ways to check for straight and square in any chassis and suspension, it is correct.

Originally Posted by 67swb72klb

good info doc thanx for the rite up

Anything I can do to add to the forum in a positive manner!

Originally Posted by Mike_82_Shortbox

Nick,

My truck was a rebuilder, put together by a couple of guys who did a repectable job; there really aren't any rattles or squeaks to speak of... But the truck was hit at the front left frame rail, and I think that unsquared it a little, giving me the left thrust angle. Push the left rail back, and it turns the rear axle to the left.

The alignment guy said he has seen these old Chevy trucks with angles of plus or minus .45°, and it didn't hurt the alignment or make the truck pull, or make it hard to center the steering wheel. I would imagine that to actually be visible following a rig, it would have to be off by 5 degrees or more.

Anyway, I've driven the truck for a couple of days now, and it corners better than ever, drives straighter and truer, and the wheel unwinds from turns in a predictable and positive manner.

So I decided to spend a thousand bucks on new wheels and tires!

Thanks again!

Mike

I am like a proud Papa to know that this is valuable info that not only can you guys use but has such a great impact on how your truck performs and your enjoyment. Thanks for the additional info.

[hairlesshobo]

Mike, everywhere I have read failed to mention anything about the brakes needing to be locked in order to use a caster camber gauge. Would you be willing to explain why? Iljke to know how/why something affects something else when I do it, and I definitely want to make sure I take my time and do it right.

Also, i have yet to find a shop in town that does even a decent job at an alignment, especially one that you can ask for something other than what their computer says without them arguing with you. Plus, every shop I've been to here wants a minimum of 75 for a real alignment.

[BMERDOC]

I never explained that the brakes needed to be locked down either. I have been under the assumption that most would sub out the alignment. I haven't explained at home alignment because I have had a machine at my disposal for years now and haven't had to perform an alignment in that manner. As far as good alignment shops, I think its because you toss the key to them and tell them to align it. Leaving them to their own devices can cause them to be lazy. You would have to search out a shop that would be willing to work with you on the specs.
In short, the brakes need to be locked so that the wheels don't move as you complete the caster sweep. The lock tool is picturd in a previous post. A steering lock is also shown to keep the steering wheel straight as toe is adjusted.

[Mike_82_Shortbox]

Originally Posted by hairlesshobo

Mike, everywhere I have read failed to mention anything about the brakes needing to be locked in order to use a caster camber gauge. Would you be willing to explain why? Iljke to know how/why something affects something else when I do it, and I definitely want to make sure I take my time and do it right.

Also, i have yet to find a shop in town that does even a decent job at an alignment, especially one that you can ask for something other than what their computer says without them arguing with you. Plus, every shop I've been to here wants a minimum of 75 for a real alignment.

Hobo,

Sorry, I am in Oregon, and I know prices vary widely.

I don't really know if you need to lock your wheels or not. I don't know what kind of equipment you are using. But in order to properly measure the caster on an alignment machine, the brakes have to be locked so that the alignment heads will not move off-axis, and allow them to measure the caster angle.

For the left wheel, with positive caster, a line drawn from the center of the spindle will move in an upward arc when the steering wheel is turned right, and downward when it is turned left. That angle from horizontal is the caster angle, and it can only be measured by machine when the brakes are locked.

Your guage may work without having to do this, but I don't see how...

Mike

[hairlesshobo]

Originally Posted by Mike_82_Shortbox

Hobo,

Sorry, I am in Oregon, and I know prices vary widely.

I don't really know if you need to lock your wheels or not. I don't know what kind of equipment you are using. But in order to properly measure the caster on an alignment machine, the brakes have to be locked so that the alignment heads will not move off-axis, and allow them to measure the caster angle.

For the left wheel, with positive caster, a line drawn from the center of the spindle will move in an upward arc when the steering wheel is turned right, and downward when it is turned left. That angle from horizontal is the caster angle, and it can only be measured by machine when the brakes are locked.

Your guage may work without having to do this, but I don't see how...

Mike

For reference sake, this is the gauge that I am using: http://www.longacreracing.com/catalo...id=129&catid=5

Even though I didn't have much room to work when I tried to look at my alignment yesterday, I was in fact able to try out the gauge and get a feel for how it works. I re-read the directions that came with the gauge about 10 times before starting. It appears that the brakes don't need to be locked when doing an alignment with the bubble style gauge. I assume this is because when you do your 40* sweep, you sweep out first, rotate the gauge until it is level with the ground and set caster to 0*, then sweep past center to 20* inward and rotate the gauge again to be level with the ground. With this in mind, they expect you to rotate the gauge when setting caster so if the tire were to roll a little, it wouldn't make much of a difference because you have to re level the gauge each time anyways.

I still think it's a wise choice to lock the e-brake anyways just to make sure it doesn't try to slip off the turn plates or anything like that.

Just my thoughts about this, but who knows.. I may be completely wrong, won't be the first time.

-Steve