[FJK1]

99 F250 4X4, 160 K miles

As the title says, the steering wheel can oscilate left & right while going straight ahead. If you hold on to the wheel, you can still feel it. What tends to start this off is a left turn. Right turns tend to stop the oscillation. I'm thinking this is a hydraulic problem, but I am open to any suggestions. Also noteworthy, with vehicle stopped, turning the wheels left you can feel a bind or hard to turn point; turning wheels right with vehicle stopped is normal through steering travel.

Any help out there?

 

[Oneof6]

Doesn't sound necessarily like a hydraulic problem description to me. Hydraulically why would it bind in one direction and not the other, why would it hydraulically oscillate? Many people complain about these front ends, drift, looseness, steering oscillation. I am making an assumption, since you didn't write about it, that no one has tightened up the adjustment nut on the steering gear box. With a unit with 160K I would start at the wheels and work inward. Check for mechanical looseness / roughness in the wheel bearings, looseness in the ball joints and steering arm components. See what you find there. Probably get more hits on youre question to repost it in the 7.3 forum.

 

[fordsforever73]

Simple test for a seized front axle u-joint: Jack up the front end off the ground with the steering wheel to one side. Then lock one hub at a time and spin the tire. Any binding indicates a seized u-joint on that side.

 

[FJK1]

Yes, I should admit I have a siezed u-joint on the RH passanger side. Do you think this would be causing my symptoms, even if the hubs are unlocked?

 

[panhead5]

Front axle u joints will absolutely cause this along with a host of other problems ,including tearing out the center of the auto locking hubs.The front axle shafts aren't always totally stationary and depending where the halfshafts end up the wheel can oscillate or worse you can barely turn the steering wheel.Other times it feels like you are driving on ice.A broken belt in a tire can also cause this concern but I doubt this is the problem.

When diagnosing these kinds of problems you have to know all parts involved are operating correctly or right even if you don't think they're related .

Hope this helps .

I do this for a living in a Ford dealership.

 

[Oneof6]

Yes, I should admit I have a siezed u-joint on the RH passanger side. Do you think this would be causing my symptoms, even if the hubs are unlocked?

Always a good idea to give all obvious known elements of a problem with the question, helps people to help you :thumbsup:. Siezed ju-joints could create the symptoms you described in your original post.

 

[FJK1]

Thanks guys. The reason I didn't mention the siezed u-joint at first is that I did not want to lead the discussion that way, I wanted all of your fresh thoughts on the subject. I spoke to a really good independent shop that specializes in PSD, & they raised the u-joint issue as well. These guys come highly recommended. The u-joint issue would have to be fixed regardless. Due to recent health issues, I'm going to let those guys do the repairs. They have the proper tooling for installing those shaft seals.

What amazes me is that left turns initiate this problem, but not all the time.

FJK

 

[fordsforever73]

What amazes me is that left turns initiate this problem, but not all the time.

FJK

That's because the u-joint is more than likely seized on one axis. When you steer in 2wd, the axle shaft pivots only on one axis. So, depending on which axis (seized one or un-seized one) the shaft happens to be pivoting on, you may have good steering one minute and wonky steering the next.

 

[FJK1]

Fordsforever73

Good explaination, but my tired old brain might not be able to think the whole thing through. Would that mean the u-joint, although not driven in 2wd, would still have to rotate through some means, to get the siezed plane in some position to create the problem? If so, what or how does the u-joint rotate. I think you have more brain power on this subject than I do.
Thanks, FJK

 

[fordsforever73]

Brain power...maybe a little...more like lot's of experience. Judging by your comment, are you saying that you are driving in 4wd all the time?

 

[FJK1]

No, I'm not driving in 4WD. Manual hubs are unlocked, I'm in 2wd when this is occurring.

 

[fordsforever73]

OK, I'll try top explain this better... So as you drive the front axle shaft still spins, although freely as there is still some friction to cause it to spin. The axle shaft needs to "bend" at the u-joint in order for the truck to steer. When you steer the steering knuckle moves and "bends" the axle shaft...imagine a line going straight thru upper and lower ball joints. That line goes down one axis of the u-joint so the shaft needs to bend on the top and bottom cup of the u-joint.

Let's say that the top and bottom cups are full of grease and not seized. In this case, the shaft will bend with ease and cause no ill-effects with steering.

Now, if the shaft happens to be on the other plane (shaft spun 90 degrees) and the other two cups are now at the top and bottom and those cups are dried up and seized, the shaft won't bend so easy when you steer. You'll get binding, snapping, popping sounds as the shaft is trying pivot. This is where you get the wonky steering. It will also put extra strain on the steering pump (can cause the pump to whine).

If you happened to get weird steering (not returning to center or stiff) all the time. Then you would consider the possibility of seized ball joints. And in this case (I'm sure yours are just u-joints), if a person had to replace their ball joints, I always recommend they change the u-joints at the same time as there isn't much more labor involved to go that extra step. I also recommend using greaseable u-joints and ball joints so they can be maintained at regular intervals.

I hopes this helps more...other than showing you in person that's as good as I can explain it on "paper".

 

[FJK1]

Excellent explaination. I'm sure this helps everyone that reads this post understand what is happening. For me "So as you drive the front axle shaft still spins, although freely as there is still some friction to cause it to spin." explains why it happens sometimes and not at other times.

Thanks, FJK

 

[FJK1]

Replacing the u-joints on both axles solved the problem. The ball joints were replaced as well, but I believe the steering oscillation was a u-joint isssue.

Thanks all, FJK