I just installed a Fabtech 2" leveling kit (spacer blocks) on my 2008 F-350 PSD 4X4 LWB CC. Somebody just asked me if I had the front end re-aligned. I said no and for the life of me don't see a reason to have it done because of the monobeam drive axle. If somebody here thinks it's necessary, I need it explained to me as to why. Thank you to all that may reply.

HAVASULEW

 

The reason is because the axle pivots at the rear of the radius arms and as the axle drops it changes your caster angle. I just installed a Donahoe Racing 2.5 leveling kit and it came with new cams to install in the upper ball joint which corrects the caster. I had it checked the next day at the tire shop and it was dead on specs.

 

Thanks bmgm37. My calculations indicate that the axle moved approximately 3 degrees down in relation to the frame. I am not really convinced that any adjustment to caster is necessary. I didn't notice any change in handling of the truck. I did notice the 2" increase in ride height immediately when I got in the truck. I will be very sensitive to handling issues at this point. Time will tell if the lift becomes an issue. Thanks for your reply.
HAVASULEW

 

A 3 degree change in the caster angle is severe. You will probably end up with a truck wandering all over the road (no center feel on the steering) once the ball joints wear a little bit. The 3 degrees will also cause your front end components to wear faster, like your ball joints.

 

Yes with the leveling kit on a radius armed front end you have changed caster to the negative which can cause wandering and a feeling of constantly correcting your steering wheel. If the change truely is 3 degrees that is a very large change but I doubt the change is that much at the ball joints. Most chain shops will offer a free alignment check.

 

I am not sure of the exact caster angle change. However I will take the advise and have the front end alignment checked. I will post the outcome, hopefully with exact specifications.

 

I used to have a Daystar 2-1/2" leveling kit on my 2005 f-250 and had no steering problems at all. I did not have to have it aligned.

 

Here is a good example to clear up why caster changes when lifting a coil spring model.



When you turn the steering wheel, the front wheels respond by turning on a pivot attached to the suspension system. Caster is the angle of this steering pivot, measured in degrees, when viewed from the side of the vehicle. If the top of the pivot is leaning toward the rear of the car, then the caster is positive, if it is leaning toward the front, it is negative. If the caster is out of adjustment, it can cause problems in straight line tracking. If the caster is different from side to side, the vehicle will pull to the side with the less positive caster. 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.

The best way to visualize caster is to picture a shopping cart caster. The pivot of this type of caster, while not at an angle, intersects the ground ahead of the wheel contact patch. When the wheel is behind the pivot at the point where it contacts the ground, it is in positive caster. Picture yourself trying to push the cart and keep the wheel ahead of the pivot. The wheel will continually try to turn from straight ahead. That is what happens when a car has the caster set too far negative. Like camber, on many front-wheel-drive vehicles, caster is not adjustable. If the caster is out on these cars, it indicates that something is worn or bent, possibly from an accident, and must be repaired or replaced.

 

That's a good explanation of caster. It is essentially the front or rear orientation of the axle housing/wheel mounting location. You could put a straight edge, lined straight up and down, on the outside of your tire and as you lift the vehicle the straight angle (90* from the ground) would change or rotate.

Realize that your suspension has fixed components. This includes the drag link/tie rod/center link, radius/control arms, etc. When the height is lifted these fixed items angles will change. The caster changes because the radius arms/control arms are fixed. Some kits will have adjustable arms which will allow changes in caster, or possibly have a "cam kit" that allows the angle of the radius arm/control arm to change slightly for changes in caster. When the fixed item angle changes it pulls your axle housing to a different angle or location (hence the change in caster). This can also change the relative location of the axle side-to-side because of the drag link/tie rod unless you have them adjusted. There are adjustable tie rods/pan hard/track bars/radius or control arms and brackets to re-center your axles under the vehicle. When you lift your vehicle, and you have fixed radius/control arms you're pulling your axle back in the wheel opening, albeit the tires are usually further away from the sheet metal because your sheet metal is now lifted or higher.

A small lift doesn't affect it much, but it would some. Because of this dynamic change, although slight in any given direction, you should have an alignment done on the vehicle.

 

Thank you high ho silver. Are you really the lone ranger? Just kidding! Very good explanation. I am aware of the situation with the 2" lift. The direction I was going was where Ace! went. I have an alignment scheduled for 11am tomorrow (the 28th). Iam very curious as to how much correction will be required. I hope that I can get the info from the technician that I want. I will post as much detail as possible.

havasulew

 

OK--here it is!!!!! Had the tech check the alignment. It was just as Ace! and I expected. Any change to the caster because of the 2" lift was minimal. I guess I would say that now I have a little peace of mind. Because of the kind of guy I am I am sorry that I didn't check the alignment before and after front bumper installation and before and after 2" lift. At this point it's too late but the info would be interesting. As the truck sits right now the caster angles are as follows: left side + 2.7/ right side +2.4. Specifications for caster are +0.5--+3.1. I feel that the truck is and will be just fine for years to come. If anybody has any questions just let me know. I'll be more than happy to offer an opinion. But, y'all know how opinions are.

 

Well thats good to hear! It good that you got it checked anyway.