Gary Lewis Posted March 18 Author Share Posted March 18 I put a redhead box in about 9 years ago. Even with the crappy old box, it still didn't return to center any different although I have adjusted this box both tighter and looser over the years and it hasn't made much difference for return to center. Get this, if I back out of the driveway it has extremely good return to center all the way to the wheels pointing straight but not going forward. Truck also has king pins, that's why I bought the offset radius arm bushings to try and help get as much caster along with restoring the ride height to what I assume stock would have been with the new coil springs. One thing I will say is the faster I drive the truck the less noticeable the problem seems to be. Flying down the highway at 60 MPH plus it's really not noticeable at all as far as driving it, only at slower speeds. If the box isn't too tight then it sounds like you may not have enough caster. My limited understanding is that caster causes the tires to return to straight-ahead. Link to comment Share on other sites More sharing options...
ArdWrknTrk Posted March 18 Share Posted March 18 If the box isn't too tight then it sounds like you may not have enough caster. My limited understanding is that caster causes the tires to return to straight-ahead. Imagine the front wheels on the shopping cart... I understand a lot of geometry from building race bikes. The fork yokes have offset and then you have the fork angle, forward. Project a line through the steering headstock. And determine how far behind that point the contact patch of the front wheel is... Link to comment Share on other sites More sharing options...
Gary Lewis Posted March 18 Author Share Posted March 18 Imagine the front wheels on the shopping cart... I understand a lot of geometry from building race bikes. The fork yokes have offset and then you have the fork angle, forward. Project a line through the steering headstock. And determine how far behind that point the contact patch of the front wheel is... Just thinking about the contact being behind the king pin makes it easy to see how positive caster causes the wheel to return to center. Link to comment Share on other sites More sharing options...
ArdWrknTrk Posted March 18 Share Posted March 18 Just thinking about the contact being behind the king pin makes it easy to see how positive caster causes the wheel to return to center. 4x4 is very different than 2x4, ad I don't know... Link to comment Share on other sites More sharing options...
FordFETruck Posted March 18 Share Posted March 18 4x4 is very different than 2x4, ad I don't know... I did the alignment this morning. After setting the toe to 1/32" in each side for 1/16" total I measured caster and camber. Driver side camber is .5 degrees positive and 1.5 degrees positive caster. Passenger side is 1 degree positive camber and 2 degrees positive caster. That explains the lack of steering return to center. Truck drives good but on flat roads sometimes has a slight drift to the left due to the caster differential so I may adjust the passenger side radius arm bushings to take a little differential out. Drives straight as an arrow on most crowned roads though. Drives well other than the crappy return to center and it is a LOT smoother than it used to be up front and bump steer is all gone. I take it the I beams need bent to correct the caster issue. Link to comment Share on other sites More sharing options...
Gary Lewis Posted March 18 Author Share Posted March 18 I did the alignment this morning. After setting the toe to 1/32" in each side for 1/16" total I measured caster and camber. Driver side camber is .5 degrees positive and 1.5 degrees positive caster. Passenger side is 1 degree positive camber and 2 degrees positive caster. That explains the lack of steering return to center. Truck drives good but on flat roads sometimes has a slight drift to the left due to the caster differential so I may adjust the passenger side radius arm bushings to take a little differential out. Drives straight as an arrow on most crowned roads though. Drives well other than the crappy return to center and it is a LOT smoother than it used to be up front and bump steer is all gone. I take it the I beams need bent to correct the caster issue. Yep, you don't have enough caster. Here's what the shop manual says: Link to comment Share on other sites More sharing options...
FordFETruck Posted March 18 Share Posted March 18 Yep, you don't have enough caster. Here's what the shop manual says: Yeah I have done some research in the past it should be around 4 degrees minimum for positive caster. Surely this pile rider didn't leave the assembly line like this. Everything on the front end has been replaced and is in good condition and right height up front is good. I wonder what gives, the truck has never been in an accident before and both radius arms appear to be the same shape - neither look oddly bent from one another. Link to comment Share on other sites More sharing options...
ArdWrknTrk Posted March 18 Share Posted March 18 Yeah I have done some research in the past it should be around 4 degrees minimum for positive caster. Surely this pile rider didn't leave the assembly line like this. Everything on the front end has been replaced and is in good condition and right height up front is good. I wonder what gives, the truck has never been in an accident before and both radius arms appear to be the same shape - neither look oddly bent from one another. I'd wait for the springs to settle before I bothered. Link to comment Share on other sites More sharing options...
Gary Lewis Posted March 18 Author Share Posted March 18 I'd wait for the springs to settle before I bothered. Good point, Jim. The springs will settle and the caster will change. Link to comment Share on other sites More sharing options...
FordFETruck Posted March 19 Share Posted March 19 Good point, Jim. The springs will settle and the caster will change. I decided to adjust it some. I gave it a little tweak on the passenger side and drove it. Seems to have straightened it out on flat roads. Link to comment Share on other sites More sharing options...
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