Interesting "driveability" issue, anyone else notice this?

[reamer]

All new suspension bushings, All new Tie rods/ drag link New C-bushings, new Blue top Box, Tight rag joint, 4 degrees caster, proper toe, on a straight long road, doing, say 45mph, and steadily accelerate. just taking the foot off the gas, (no brake touching) the nose will drop and the truck cuts to the right.....
I understand the nose-dropping part, Thats the rear leafs squatting under acceleration, but what causes the truck to cut to the right?

 

[Yooper74]

Trac bar and steering link parallel?

 

[knack]

My Bronco changes direction a bit when I get off the gas. I think it's a characteristic of the rear locker. Open diff on yours, or a locker?

 

[bax]

Locker in the rear? If you have a Detroit that is pretty typical. If you can drive in just front wheel, do the same test. See if anything changes

 

[rjrobin2002]

You got bump steer I would say. Jump on your front bumper and see if your steering wheel moves.

 

[Shimmy]

my initial thought would be bumpsteer. it may not be enough that your DR and TB are parallel. they need to follow the same arc.

i've also read about the locker causing it but i've never experienced this on any car i've owned with a rear locker

 

[DirtDonk]

You said all new tie rods. What type? Just stock replacements, or the double adjustable kind?

Suspension lift? if so how much?
And when all is said and done, got pics of the front linkage and suspension?

 

[reamer]

Open diff, Drop trac racket, drop pitman, WH adj tie rod ends. 2.5 new WH lift, parrallel Trac and Drag..

 

[Broncobowsher]

Parallel doesn't mean the arcs are matched, just a better chance of it.
Take the front shocks off. Clamp something solid (angle iron works) between the tie rod and the axle tube. This will lock the steering. Now bounce the front (why you took the shocks off). Watch the steering wheel. If it stays straight, you don't have bump steer. If it is sawing back and forth as it bounces, you still have bump steer.

Another one to check, leaf spring bushings. Primary the front bushings. If one side is more shot than the other, as you get on and off the gas the rear axle will shift forward and back just a little. Enough to notice, not enough to tell it is the rear end that is the issue.

Tire wear can be another. I once caught some nails in the road with my daily driver. Both right side tires were stabbed through the sidewalls and got replaced. Lazy tire shop, new tires on one side and fairly good tires on the other. I could do a slalom without touching the steering wheel. Just on and off the throttle. Really wasn't that much difference in tire wear. Put the pair of new tires on one axle and it was fixed.

There is another one, but with your list of parts I don't think it is possible. When you don't have drop bracket/pitman arm, but the linkage is still aligned and not bump steer. Bum Yaw. This is a fun one. The truck drives straight down the road. Dips in the road don't upset the steering wheel or the track. But the body/chassis rotates as the front suspension cycles. Steep drag link angles shift the front side to side more dramatically than flatter angles. But can do so without actually being bumpsteer since the steering and tracking are maintained.

 

[DirtDonk]

With the fully adjustable tie rod did you make sure to rotate it up so that the draglink meets it at a 60° angle? That would be basically with the grease fitting pointed up at the bottom of the radiator.
Making sure this is done definitely makes a difference.

 

[SteveL]

Check u-bolts on rear end.

 

[reamer]

will do