This is a F350 D60 swapped under my '96 F250.

I didn't notice until a few days later that they labeled it a F250 but the should have used F350 specs.

I am chasing a shimmy (It is not tire balance) at about 35 and 65. The frequency of the shimmy is the same regardless of speed, but the amplitude changes with speeds.

I want to make sure the basics are covered. Do these look right?

 

like 1/16 negative toe.
after Bashby correcting my senior moment, i set toe in 1/16, or positive toe

 

Toe in is positive. I usually set them about 1/16" in. That isnt causing your shimmy.

 

yea, i had a senior moment there Bashby.

 

Thanks, I am open to your suggestions.


Tonight I added another 2-3/4 degrees of positive caster to each wheel using adjustable sleeves.

I left the camber the same.

As both top ball joints were pivoted back the same amount I do not believe the toe changed.

There are the predictable steering nuances of 6 degrees of caster. But those are more about other issues.

The 35 mph shimmy seems slightly affected but this could be just optimism.

The 65 mph shimmy is basically unchanged. Overall, no improvement.


Maybe related, maybe not. But everything is now so soft that I can make the truck wiggle in the driveway by pushing/pulling sideways on the rear hitch. This isn't the truck rocking side to side. This is the headlights swinging left and right. I'll try get a short video of this.


In the absence of suggestions or success elsewhere, I'll go the opposite direction with the caster and take most of it out.

Thanks to all following along...

 

Had some free time during lunch. Turned the tie rod adjuster 5 turns toe in and went for a quick drive.

The shimmy is still present.

When it is shimmying (Is that a word?) is feels more solid. Not sure how to describe it, just that instead of everything sorta shaking, it seems I can feel it moving in a more controlled manner.

The speed window that is shimmies is narrower. It used to start about 60, worse at 65, sorta smoothening out at 70.

Now it won't start until 63, and smoothens about 68.

 

I took the adjustable sleeves out, reset and installed them removing 2-3/4 degrees of castor leaving about 1 degree of castor.

And went for a drive, fully expecting the near zero caster to cause all sorts of shimmying and other steering chaos.

If I hadn't have changed the sleeves myself I might not have know there was any change at all.

I believe the dramatic toe-in is has made the onset of the shimmy harder to start and it settles quicker as the truck goes through the critical mph range, but caster seems to have very little affect.

I am heading out to put the stock 0 degree sleeves back in.

I will take it for another drive with the toe set 5 turns in before I back some of those out.

 

Evening, when the swap was done did the panhard (track) bar from the f350 get installed too?

 

Zero degree sleeves are back in so the caster should be very close to the alignment specs in the pictures above.

Test drive with 5 full turns of toe-in gives about as good as it has driven so far! I am almost excited. (Notice no exclamation mark.)

Almost no shimmy felt at all speeds.

There are some wiggles that I don't think I'll ever get rid of. These are the kind that make the door panels rattle. Not extreme, just very low in the vehicle, like they are at floor or ankle level.

But, the tires are making letting their displeasure heard about being dragged in such a toe-in fashion.

5 full turns in from almost zero toe in is where I started, so I went back out 4 full turns.

The shimmy was back, not so bad as to spill your capped latte, but it better be in your hands and not any of the cup holders.

Added a full turn back in (2 full turns of toe-in from zero) and took a test drive.

The shimmy wan't gone, but was now more of a nuisance than an embarrassment.

I think with some tire pressure changes this is almost a livable set up.

I also think that new shocks will help too, though more for the low speed (10-50 mph) wiggles.

I'll add more as I make changes.

 

What tires are you running on there and how old is the steering stabilizer?

 

Brand new cheapo 285/75/16 tires on factory alcoas.

No stabilizer before the D60 swap. None now either.



Yes.

The stock length track bar was a little short and the tension caused a nervous feel.

I now have an adjustable track bar that uses poly bushings instead of heim joints.

 

I've seen your truck in other threads, looks good!! Love those Ranch Hands! Are you still running those hummer take-offs? I've had several sets of those on various trucks. Are they what you've been running when you experience the front end issues?

 

I took them off awhile ago thinking they were horribly out of balance. All of the alignment figures and changes in this thread have been with the same set of new tires in factory rims.

The third time I took them to get balanced I had them 'road force' balance them. The tech took me out to the shop to show me how good these were balanced. They understood my belief that I was having tire issues, and didn't treat me like an idiot, but they felt confident that the tires were not out of balance or out of shape. This is what led be to look closer at the behavior of the truck.

I have an errand to run today so I'll have a few highway miles to see if I have this thing about tamed. I still think there is more to this than a simple toe-in adjustment.

The military tires will go back on soon as I don't have any pics with them and the new lift.

I so tried to avoid the ranch hand bumper but the OBS makes them look good. Dang they are heavy though. I was going to have them sand blasted and re-powder coated. But a quick squirt of black rattle can makes for cheap upkeep!

I like 'cheap' when it makes sense.

 

Yeah, I was going to say it'd been my experience that even if those 37" radials look good they could have been compromised on the sidewalls (thin from running flat) but your not running them so forget that..
I cant find those bumpers used anywhere up here in New England and I'll be damned if I'm paying full price for those suns-a-bi!$ches.....

 

Update:

I've installed a 3" track bar drop plate and a 3" drop pitman arm. %97 of the bump steer is gone. I think the last %3 is not gone because a 3" drop pitman arm is not 3" of drop over the stock pitman arm, rather it is simply 3" of drop versus being flat. The stock F350 arm has about .6" of drop. So a 4" drop pitman arm would be closer to equaling the true 3" drop track bar plate.

The shimmy is no better or worse after the dropped track bar or pitman arm.

Installed 4 new Bilstein shocks. I've started another thread about wanting more dampening. But these are a definite improvement to the ride.

Removing the front tire does make working on the shocks a little easier. But the shocks could be changed with the tire in place. With the few inches of lift that I have I could have simply worked over the top of the tire. Removing the rear tire provides zero help for the rear shocks.

But, I used this as a reason to swap the front right tire with the rear left tire. Opposite for the other side.

The shimmy is no better or worse after the shock install and the tire rotation.

The search for the cure continues... I wonder if some camber would help...