I recently bought an '82 F100. The PO had done some things to it in the suspension department. he replaced the front springs and associated parts, new shocks etc. From his paperwork it was aligned and then went back 3 weeks later. So there was an issue. That was a couple years ago, not sure the miles since then. But I don't suspect a lot. So now that I have it, I'm ironing out issues. It pulls to the right. You let go of the wheel and it takes a rather strong pull to the right. The tires that were on the truck were not worn, at all. I changed them as I didn't like them, so new tires are on it now. I have a Smart Camber tool that I have used for my Mustang restorations, etc. It works well and has done everything I need it to do in the past. I checked the camber on the truck and it was slightly positive, .6 on the left and 1.1 on the right. I removed the right front and found that there was a 1 degree bushing installed. I turned the bushing 180 and added negative camber. I took a short drive, no real difference in feel or pull. I then rechecked the camber angle and it was -.9. I then turned the bushing again, to the middle of the two and added a bit of caster. I went for another drive and it was definitely better, it had changed, but it still pulled badly, just not as bad. I rechecked camber angle and it is positive .1 . My Smart Camber is ready exactly what it should be reading pertaining to the changes I made with the 1 degree bushing. So right now, I have positive .1 on the left side and negative .1 on the right. I cannot measure caster, but that wouldn't be creating the strong pull I have. I probably should have added a bit or negative caster instead, but still not my issue I have now. Ball joints are good, PO replaced both lowers. When I has the right front apart, the upper joint is tight, feels better than the lower There does not appear to be any accident damage to the frame, and like I said already, no tire wear at all when I received the truck. So my question is . .where do I start looking next? Thoughts from anyone that is experienced with these I beams with ball joints?

 

I'm sure you know more than me just a caution I think you can get different camber readings if you back up compared to pulling forward. Sounds like you've got all that well covered though. I would try a few turns on the tie rod adjusting sleeve(s) and see if it gets worse or better. Or start with a DIY home toe-in check

 

I drove the truck between readings. So it wasn't a let it down roll it back and forth, it was driven. As for the toe, not going to cause the issue I'm having. Typically toe causes tire wear, across the tread. Because it centers itself as you drive, toe isn't going to have a strong effect on one side or another. I have a Toe Tram as well,.thanks

 

You should be shooting for 0.75° to 1° positive camber, and 4°+ Caster,
and the old stand by of 1/16" toe in.

There may be a thrust angle issue at play that is messing things up.

 

An alignment guy told me the caster being off one side to the other will make it pull. I would not think camber would be important except for tire wear.

If you could measure it, when you turn the wheel left to right, the truck frame actually raises and lowers in height from the ground. This is caused by caster. If the caster is different side to side, it makes the frame want to settle with the wheel to the right or the left.

 

I know that years ago, in NY we would set the caster 1/2* more + on the pass side to allow for the road crown.
Trouble nowdays is that most alignment shops have computer read outs and if it's "in the green" it's ok. Many manufacturers have a + or- 6* or more in their specs.

 

Camber is a huge factor in the vehicle tracking forward and straight. have you ever noticed on a circle track cars how the geometry is set up to allow them to turn better? And yes the suspension raises and lowers as you turn, that is why you set the camber with the wheels straight. When vehicle is going straight, the caster angle makes no difference in the ability to stay straight ( in a perfect world with no steering input ). Caster comes into play when you turn the wheel, as you mentioned already.
yes George settings are slightly different left to right if it is done correctly. About 1/4 degree in camber is typical. What I did this morning was check the ride height of the suspension. I found the right side higher. The left is typically about 3/8" higher. So mine is off big time, have the wrong side higher. I will get that set and see what it does then. Still open to thoughts. Thanks guys.

 

I disagree, caster is very important from what I understand for tracking going straight. Camber changes in a turn to try and keep the most tread on the ground for traction.

If you could get rid of gravity, then caster would not have any affect. But I had my say, I will bow out of this thread and quit clogging it up.

 

Not quite true, caster is what makes the wheels want to keep tracking strait and not wander all over.


The king pin angle or steering axis inclination is what determines your scrub radius and assists the wheels returning to center after turning, it is what lifts the vehicle up when you turn the wheel, the caster angle then helps keeps the tires tracking straight and mitigates/stops wandering.


And that whole cross caster/camber thing for road crown had a purpose once, but not any more and I advise against it in any vehicle today.


Since you are adjusting the camber with bushings you will be messing with the steering inclination and scrub radius. Provided the steering inclination is correct you should be fine. But if the springs are worn and the truck is not sitting at the specified height/level or the wrong size tires are fitted or something is bent, things could get goofy pretty quick.
The wonders of the TIB suspensions great in practice and nearly indestructible, but a real bitch if things get out of whack.

 

I went through this with my '87 years ago. Three different computer alignments, and it still pulled to the right and wore the outside of the right tire.

One alignment they had put a different bushing in also. The problem with mine was the factory specs are not correct for good driveability. I finally tried it myself and kept turning my bushing more and more for positive caster, and each time the pull was better. I went to the point of it pulling the opposite direction, then backed it off some. I then set the toe with a ruler.

That stopped all my pulling and wear on my tires. In fact, the tire dealer told me a few years later when I bought new tires mine were the most even worn tires he had seen on a 4x4 TTB truck.

17 years later I still have the truck, and still have not touched the caster/camber settings. I did replace the radius arm bushings and axle pivot bushings last year. I set the toe with a ruler again, and all is well.

Caster will really mess with the direction a vehicle pulls, even if it's in spec. One side could be in one end of the spec, and the other side on the opposite end of the spec. The cross difference between the two will cause a bad pull, but still be in spec.

 

So here is what I have done. I played with camber changes and offset bushings. I got the camber within spec, but it still pulled right, pretty badly although somewhat better than before. So I checked ride height and found a large difference. I was 3/4" different from side to side and the right side was higher. This is not correct. The left side should be higher if anything. I went reading and found where ride heights were mentioned and even saw where some thought the right side would be higher because of the crown. No this is not correct. It is the left side that should be slightly higher and it IS because of the crown. The left side should be from 0- 3/8" higher than the right side. The vehicle will drift towards the higher side. So anyway, on to make the changes. Looking more closely, my right side had a steel shim under the spring seat mount. That just shouldn't be. I pulled it out, it was only .145 thick. So not enough to make the needed height change, even if I put it on the left side. So I had to weld some round stock to the shim to make it thicker. I ended up with a shim about 5/8" think. Add the .145 I removed from the right and I made a 3/4' change. I assembled it all and went for a ride. I did not change the camber or toe, etc, just went for a ride. HUGE difference. It does still go right, but not NEARLY as fast or violent as before. I will play with the camber and such again possibly tomorrow or the next. But not at least, I have a ride height that is at or very close to spec. Why it was off so much before?? The PO had replaced the coil springs, maybe the shim was on the left originally? I don't know. But it was clearly not right as it was.
Caster effects tracking yes, but it doesn't create a strong pull like camber does. When you release the wheel after a turn, caster helps get it back on center.

 

The steering axis inclination is what actually returns you to center. caster can assist with this but with 0° inclination you wont return back to center, regardless of caster.

 

Look, if you are in a perfect environment, no forces other than your forwards motion. You can change the caster to whatever you want, the vehicle will still go straight. You change the camber on the same vehicle under the same situation and the vehicle will not go straight. This is what I have been saying. It is true. Now we don't operate under these situations, so alignment is obviously more complicated and one where you have to try and satisfy all areas as best you can.
The severe pull I was experiencing was not because of a caster problem. It would not make the severe pull I had. I knew that. If I let go of the steering wheel, on any road, you literally would be on the shoulder in less than 2 seconds. And this is why I have attacked it as I have. And I have made huge progress, mainly in the ride height change

 

I think you are over simplifying it. Camber won't determine if you go strait or not. Cross camber will, as cross camber changes the scrub radius of the tires side to side.

Cross caster and uneven inclination angle has a much bigger affect if you pull in one direction or another aside from creating uneven geometry it can also create an uneven scrub radius.

In the ball joint equipped TIB's you can have the same camber side to side yet sill have pulling if the steering axis inclination is not the same side to side which is affected by uneven ride height side to side.

Caster keeps the wheels wanting go in the direction they are facing and prevents wandering. Steering inclination is what makes the tire/ steering wheel want to return to center and go straight, in many suspensions set ups camber and inclination angle are tied to each other, but not all like in the ball joint TIB With proper steering inclination and caster the chamber can be what ever as long as it's even side to side and the vehicle will still track strait.

Not alot of techs under the base fundamentals behind wheel alignments anymore and just make adjustments to match what the machine is telling them.
The proliferation of the McPherson strut and it's derivatives has dumb'd down alignment techs as very little is actually adjustable on them so knowing the fundamentals is not necessary..

With the TIB's and especially the ball joint TIB's if you do not understand the fundamentals you can really **** stuff up trying to align them.

 

First, this is bothering me . .its straight, not strait And yes I am referring to cross camber, the difference between. If both sides are exactly the same, pulling to one side will not effect it. Yes I understand ride height is important and why I tackled that today. I have never been an alignment technician, but I did teach auto for 20 years.