01 f350 steering darting occasionally.

[Squamch]

01 f350 4x4 diesel.
Occasionally pulls left after a corner, like the steering hasn't fully straightened out. I feel resistance in the wheel, then it seems to dart back and forth as it kind of "pops" straight again. Then it will be fine for a couple of days.
Tie rod ends are good. Ball joints are good. U bolts are tight. Manual hubs are unlocked. No steering stabilizer.
Steering is good otherwise, no slop.
My power steering is weak as shit, could some kind of intermittent total failure of the pump cause this?
Any other thoughts?

 

[SLC97SR5]

Probably a front axle u-joint starting to seize up.

Jack up one side of the front axle and turn the steering wheel a turn from off of center and give the tire a sharp spin, you should see it jerk if the u-joint is beginning to give it up. You can also lock the hub to make it more apparent.

My F350 CCLB did the same thing and I thought it was nuts that an unlocked hub could cause a 7k+ truck to steer funny. The front axles windmill slightly during normal, unlocked driving.

It scared the heck out of me the first few times and took a while to figure out. I replaced the steering box and gave all the linkage and rod ends a hot supper just to discover the u-joint.


-edit

I just re-read your post and I suppose a dying pump or sticky relief valve could cause it to not want to center but I'd think that would be more consistent.

 

[total newb]

And fwiw shit brick super duty hubs dont like to unlock.

Vacuum hubs particularly but just because the dial is turned doesnt mean theyre unlocked

 

[Broncokyle88]

Probably a front axle u-joint starting to seize up.

Jack up one side of the front axle and turn the steering wheel a turn from off of center and give the tire a sharp spin, you should see it jerk if the u-joint is beginning to give it up. You can also lock the hub to make it more apparent.

My F350 CCLB did the same thing and I thought it was nuts that an unlocked hub could cause a 7k+ truck to steer funny. The front axles windmill slightly during normal, unlocked driving.

It scared the heck out of me the first few times and took a while to figure out. I replaced the steering box and gave all the linkage and rod ends a hot supper just to discover the u-joint.


-edit

I just re-read your post and I suppose a dying pump or sticky relief valve could cause it to not want to center but I'd think that would be more consistent.

This

I’ve seen it maybe a dozen times. But it does happen. More frequent exercising of the 4x4 will help to stop it from happening again in the future

 

[Squamch]

Hmmmm, passenger side u joint is non-greasable. I guess that's what I'm doing tonight then.

 

[Pmedic920]

Probably a front axle u-joint starting to seize up.

Jack up one side of the front axle and turn the steering wheel a turn from off of center and give the tire a sharp spin, you should see it jerk if the u-joint is beginning to give it up. You can also lock the hub to make it more apparent.

My F350 CCLB did the same thing and I thought it was nuts that an unlocked hub could cause a 7k+ truck to steer funny. The front axles windmill slightly during normal, unlocked driving.

It scared the heck out of me the first few times and took a while to figure out. I replaced the steering box and gave all the linkage and rod ends a hot supper just to discover the u-joint.


-edit

I just re-read your post and I suppose a dying pump or sticky relief valve could cause it to not want to center but I'd think that would be more consistent.

I agree 100% with this as well.
It’s fairly common, I’ve seen guys spend a bunch of time/ money chasing steering components only to end up at axle joints.
I’m going to be doing my own soon.
This kid spells it all out well.
https://youtu.be/pWOcFylJbsM

 

[Squamch]

Swapped axle u joints, no longer darts...power steering pump has died though, so that sucks.

 

[billybob_81067]

Ball joints will sometimes do that shit too... I put new ball joints on my old man's super duty and it wouldn't center for shit for quite a while until the new joints loosened up some.

 

[Fishnbeer]

Glad you fixed the darting problem. To be honest, I had never experienced that problem and had not even considered that to be the culprit.

Good to know

 

[total newb]

Swapped axle u joints, no longer darts...power steering pump has died though, so that sucks.

Did you fix your locking hubs while you were at it.......

 

[DMG]

Did you fix your locking hubs while you were at it.......

The hubs do t have to be locked for this to happen

 

[Squamch]

Did you fix your locking hubs while you were at it.......

Well, there's nothing wrong with them, so no.

 

[total newb]

The darting typicaly haopens when the axle shafts are spinning or of youre coming out of a turn.

Ford hubs are supremely best at not unlocking. Particularly the vacuum type. Dodges have the issue the most because they dont have hubs at all and ujoints are always rolling.

 

[rockyota83]

fwiw ive had to replace two different(not mine) pitman arms in the past few months due to them getting wallowed out, one was a 01 excursion diesel and that one the pitman arm was wallowed out at the drag link and it also had a couple splines cracked on the sector shaft(replaced the steering box too).