Alignment spec sheet help

[jonmelton]

I know there are a lot of these on here, but I want to make sure I'm not missing anything. Here is my alignment spec sheet from the alignment shop. These guys are really nice guys, but I took my bronco in there to get it aligned and they said they spent over an hour on it and couldn't figure out how to adjust anything... So yeah.

Anyways, I'm going to adjust my toe using the "tape measure" method, but I'm not sure what I should do about my camber. I've seen the shims and the bolt that adjust it, but do I need that much adjustment? I'm going to wait and see how those effect the steering before touching my caster.

My specs:
1975
7* C-bushings
Chevy disc brakes
2.5 in lift (don't know the brand)
no body lift
3-way adjustable tie rod and drag link
33" tires

 

[jonmelton]

Oh and yes, the steering is all over the place. Right now it shakes at about 45mph, but I don't think it's death wobble because when I slow down it goes away. It randomly darts but not during breaking or accelerating, just randomly. Talk about butt pucker.

 

[jonmelton]

Any camber help?

 

[DirtDonk]

Not much. Your camber is well within spec, so that's not a big problem. Sure, it would be nice to have a bit less on the left side, but the spec is 1-2 degrees positive. Just like you can see in the window on the chart.
The one "bad" side is actually perfect at just .6 degrees. You can get the other side down to that region easily with an eccentric ball-joint sleeve.

The caster is somewhat low for optimum handling, but is about what would be expected on a '75 with 2.5" of lift.
But it too is very workable. Some of us don't have even that much.

The toe-in seems a bit high maybe, but I'm still not versed well enough in "degrees" vs "inches" to be certain.
However, I have to ask... Is that negative toe in? As in, toe-out? If so, that would certainly 'splain things.

At this point, definitely play with your toe-in settings. With a fully adjustable steering linkage, I'm surprised the alignment guys didn't know how to set it. It's not like an old original setup that's locked in with rust after all. On those you really have to wrestle with it and the shop guys don't often have that much time to give.

Good luck.

Paul

 

[DirtDonk]

Oh, it's great to have the printout by the way. So not being negative at all about getting it up on a rack. Now you know what you have and can deal with it from there.
But I'd say make the time and trouble now to do it yourself.

Toe in is an easy one to fiddle with. You can simply turn the adjusters a tiny bit at a time, drive it for a day or two and see what you think. If you don't like the change, go farther or go back.
Just keep track of where you started just for a handy reference.

By the way, what steering linkage do you have, and how is it set up?
Did you set it up originally?
Got pics?

Paul

 

[DirtDonk]

Sorry, post-whoring tonight apparently...
What air pressures are you running in the tires, and have you had them balanced lately?

What type, brand and size?
How old and how many miles?
What size wheels?

Experiment with tire pressures too.

Paul

 

[Steve83]

...they spent over an hour on it and couldn't figure out how to adjust anything.

That's scary. %) That printout came from a fairly new Hunter machine, which not only has a database of vehicles so it knows what adjustments CAN be made; it also shows where to make each adjustment; and has a brief video of the adjustment being made showing the proper tool and even the direction. So if those guys can't figure out how to align one of the simplest steering systems ever installed on a vehicle with only a few adjustments...

Photos of your truck's front suspension & steering linkage might help us help you explain to them how to fix it. But I'd look for a shop with a better alignment tech; even if they have an older machine.

 

[bronconut73]

That's scary. %) That printout came from a fairly new Hunter machine, which not only has a database of vehicles so it knows what adjustments CAN be made; it also shows where to make each adjustment; and has a brief video of the adjustment being made showing the proper tool and even the direction. So if those guys can't figure out how to align one of the simplest steering systems ever installed on a vehicle with only a few adjustments...

Photos of your truck's front suspension & steering linkage might help us help you explain to them how to fix it. But I'd look for a shop with a better alignment tech; even if they have an older machine.

This /\/\/\/\

 

[dave67fd]

A vibration that starts at a higher speed and settles down or goes away above or below that speed is usually tire balance. Find a reputable shop (the one you went to doesn't seem to be the one) have them check your tire balance first and then go from there.
A pro shop with the latest Hunter equipment "will" get it right or at least let you know you have an issue with something specific.

 

[jonmelton]

Sorry, post-whoring tonight apparently...
What air pressures are you running in the tires, and have you had them balanced lately?

What type, brand and size?
How old and how many miles?
What size wheels?

Experiment with tire pressures too.

Paul

Paul, I love it when you "post-whore" I actually look for those post because I know its going to be good.

I bought the tie rod off your recommendation and installed it myself. It was so easy to install and I think it's easy to adjust. I just don't know which way to adjust it.

The tires are old, I need to replace them. They are BFG 33's and I try to run them between 25-30psi. I don't know the mileage on them, but they are worn and came with the truck when I bought it.

Here's a driving shot, I'll try and get a better one tomorrow. Since I last asked for help, I tightened down the Trac Bar bushings and the trac bar doesn't move under pressure. I also adjusted the tie rod so the grease fitting points up and the bumper and it doesn't rotate near as much.

 

[broncodriver99]

It looks like you have almost no toe in per the diagram. Your picture on the other hand looks like your wheels are pointing out the sides of the Bronco. ;D

You should have somewhere between 1/8-1/4" of toe in. It should be easy enough to adjust with the adjuster sleeves at the tie rods.

 

[Whoaa]

Take off the shimmy-shock and throw it in the trash can, it only mask "real" issues that you may need to address. Then you can easily use a sawsall to cut the ugly brackets off too.

I can almost see a little shine (shiny spot), wear mark/rubbing, on the upper trac bar bracket where the bushing is/suppose to be. Inspect that upper trac bar (frame mount) bushing very close. If that bushing is toast and the trac bar is moving around...which explains the darting issue, it could easily be the root problem of this issue.

Make 100% sure the upper trac bar isn't moving, the bolt doesn't have to be **tight**, and shouldn't be tight, because the bolt is just a pin -a hinge point and that bar needs to be able to articulate up and down easily, the magic is all in the bushing. That bushing should be in like-new condition all the time.....replace every few years as needed.

These front end's were a very poor design from the factory. Everytime the front suspension loads and unloads, and to a lesser degree engine power on/off and the rotating torque, the trac bar yanks the whole diff housing R or L in a compression/sissor effect, which in turn gives the driver the sensation of getting the whole machine thrown off the road and into the ditch -or in the other lane towards on coming traffic. Because of this inherit design flaw they can never be "perfect", but they can be made better/safer/easier driving.

EDIT: I didn't take the time to re-read the whole thread, but I thought it said 75' model? However this is a disk brake 76/77 front end? Disk brake conversion? Lets nail down exactly what spec's and what front end were dealing with here.

Regardless, I'm not a big fan of the style of draglink you're using. The drag link / trac bar alignment "appear" good/parallel -but mainly because of the funky dogleg in the drag link. I have two sets of this style sitting in the corner of my shop. There are different options for your drag link set up.

 

[Steve83]

I just don't know which way to adjust it.

The stock steering linkage has 1 adjusting sleeve in the drag link, which sets toe. You now have a redundant sleeve for toe in the drag link. The new sleeve in the inner tie rod (from the pitman arm to the drag link) sets the steering wheel angle (clear vision).

So the alignment shop should begin by centering the STEERING BOX (pitman arm), and then adjusting the inner (center) sleeve to put the steering wheel level. When they make the toe adjustment; they should use the drag link sleeve that's farthest from where they're trying to go. IOW: if they're trying to shorten the bar, use the sleeve that has more gap inside; if lengthening, use the sleeve with the smaller gap. The goal is to end up with the sleeves having roughly the same gap inside.



If you have a camera with OPTICAL zoom, set it to the max (no digital zoom), then move far enough away from the truck to get the whole drag link in-frame, and get the camera down in-line with the axles (rear axle centered vertically & horizontally behind the front) to take your pic(s). That will give us the least-distorted view of the linkages.

 

[450rbronco]

It looks like you have almost no toe in per the diagram. Your picture on the other hand looks like your wheels are pointing out the sides of the Bronco. ;D



You should have somewhere between 1/8-1/4" of toe in. It should be easy enough to adjust with the adjuster sleeves at the tie rods.

1/8 and 1/4 ? Is that total diff if I'm measuring across front the. Across the back of rear tires ?


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[DirtDonk]

Yes. But it's hard to use the sidewall as a reference point because of irregularities that might crop up at various points on the tire.

You can make some straight edges that ride on the edge of the wheel to use as a reference point for a tape measure.
Or you could mark a point near the center of each tire, put a fine but legible line (maybe use tape and a pen?) and take a measurement straight across the front. Rotate the tires 180 then take a matching measurement at the back.
The difference is your toe-in or toe-out.

As said, you want the measurement narrower at the front (toe-in) and you can start at 1/16" and simply drive it. Then, after you've gotten a feel for it's characteristics, turn the adjusters in a tiny amount to net you another 1/16" to get that 1/8" toe-in.
Ideally you want to turn each adjuster the same amount. Realistically if you find it's easier to turn just one to get one adjustment, then the other to get the next adjustment, the little bit that the steering wheel would be off the first time would be made up for the next. If you can even notice it with that tiny amount.

And the adjustable draglink is there to re-center the steering wheel no matter how it ends up. That's it's sole purpose in life and all Broncos should have come that way from the factory.

Not to add too much to your plate at one time, but it was already mentioned that you should verify one thing BEFORE ANYTHING ELSE... Sorry, was I shouting? And that is that the steering box itself is at it's "on-center" position before you do anything else. That way you can actually achieve the best possible result from tweaking all the other things.

If you're not familiar with the steps to do that, let us know and we can walk you through that part first.

Paul

 

[jonmelton]

Thanks, that helps. Can I take the tires off and measure with the disc brakes?

Also, I know how to find center with the steering (disconnecting the drag link, marking the steering wheel furthest left and right, then finding center between the marks) but I haven't yet researched how to adjust my steering wheel once I find center.

 

[DirtDonk]

Once you find center, if the wheel is off then you'll want to either:
1. pull the wheel and turn it on the shaft, or
2. pull the shaft at the box and rotate it until the wheel is centered.

Either one is "correct" but moving either one will change how the turn signal cam cancels if it's a stock wheel.
This can be good and might correct a slightly off-center wheel from a previous move. Just worth a check to see that the wheel is canceling the signal switch properly while you're doing all this.
Once the box is centered and the wheel is centered on the box, you can use the steering wheel as your reference point from then on. Knowing it's right on the money with the box is a great thing.

From that point on down the road, if the wheel is ever off center while driving, you simply use the adjustable draglink to move the wheel back to center. Re-centering the box in the process.

You can definitely use the disc rotors, but there isn't always room to get a consistently straight line from one side to the other.
But if you have the room go for it.

Paul

 

[firewalker73]

If you have wheels with no tires they will make it easy to set your toe. Also make sure everything in the suspension and steering is in good condition. The ball joints are often overlooked and with your camber numbers what they are I would check these for sure. Check and make sure the pitman arm is tight, all the tie rod ends are not loose or worn out, also check the steering gear end play. Also radius arm bushings. All of these things can cause problems.