I know in the past someone has posted a link to the actual specifications for the front end alignments on these trucks. Did a search, but didn't come up with anything.

I've got issues with my truck and going to have it checked out tomorrow and would like to know the numbers so I can compare to what he gets or recommends.

 

Here's what I have on it.

 

Thanks a bunch.

I've been chasing down a problem with my truck for the couple years I've owned it. I've replaced EVERYTHING(balljoints, inner tie rod, outers are tight, box/pump, rag joint, tires, shocks, poly radius arm bushings), tried a Rancho steering stabilizer(just made it heavier to steer but didn't fix problem).

Drives straight on smooth roads, no problems. Give it a pothole or rough surface and it gets a bumpsteer kind of feeling. Wants to move around. Strangely, if you let go of the wheel and let it bounce around the truck goes straight. If you hold the wheel firmly, trying to control the wheel whipping around it tends to throw the truck around in the lane. Like it's a rubber band hooked to it. Let it snap and it fine. Try to hold it and it rebounds the steering and moves the truck around.

I've owned plenty of Ford trucks and never had one drive this bad. I've had my '69 F100 for 24 yrs, got 150K+ miles on it(still original king pins), even has bias ply tires and it steers like a new mustang compared to this truck. It has to have a geometry problem, somehow if one wheel moves up/down it screws with toe in? Thus making it bumpsteer in a way. I've got an appt in the morning and I'm going to watch the guy and see what the numbers come up as. I want him to jack one wheel and see what happens.

Just for information, where is the ride height measured from? Top of tire to fenderlip?

 

It didn't give me ride height and my truck is a 4x4. Maybe someone else can come up with that measurement.

 

The sheet you posted shows ride height dimension, but not sure where they take it from? Tire to fenderlip?

 

Upon doing some reading, I find this information to describe my situation well:

If the caster is equal but too negative, the steering will be light and the vehicle will wander and be difficult to keep in a straight line. If the caster is equal but too positive, the steering will be heavy and the steering wheel may kick when you hit a bump. Caster has little affect on tire wear.


Looking at the chart above, it listed 5-7* positive. Seems like alot. Especially with more ride height, it decreases.

 

Guess I should have examined the chart I posted,huh?

Most are ground to a point on the frame/suspension. Unfortunately the Chiltons manual didn't indicate where to measure from.

 

Ground to suspension sounds odd. I would think the taller the suspension(spring height) would affect suspension settings more then just tire size. Being the arm runs in an arc, the taller the spring, the more the camber would be affected. A taller tire wouldn't per say screw the settings up.

The chart shows that the truck will have MORE positive camber with taller height. This meaning the tires tipped out more at the top due to arms hanging down farther from taller springs.

Guess I'll have some questions to ask tomorrow. Not that ride height is an issue, just want to know what the specs call for and if something is way outta whack.

 

Well, no good news.

Alignment was dead on. 1/32" toe in, about 2* caster. Hmmmmm.

After talking with owner of shop, he drove it a couple times we determined that possibly there is issues with my balljoints. Put them in about 2 yrs ago, grease them with oil changes(3-4K miles). Last week I pulled tires and tie rods. Greased balljoints and wiggled spindles. Seemed "smooth", but snug. Not feeling too stiff, but they weren't froze. He thinks maybe I overpulled the nuts and have them too tight and bottomed out, thus causing the stiff feeling and my driving problems. When I first replaced them after I bought the truck, the originals were about froze solid and took two hands to turn the wheel. The new ones made the steering almost too easy. Over the time, I guess it's gotten tight and never thought about it.

So, likely later this week I'm going to remove tires/tie rods and knock balljoints loose and reset them and torque them to 120 lb/ft as he mentioned. See if that loosens them up, if not I'll be putting new ones in again.

He did feel the problems I've discussed and agrees there is something wrong. With everything else dead on, that was his only thoughts.

 

When you replaced the tie rod ends you put "real" ones in didn't you/ the greasable ones? The ones set in rubber are pure crap. I had that shimmy on my 86 way back when and it went away after putting in non-rubber tie rod ends.