Steering Question (1 Viewer)

[ukboneman]

I am finally wrapping up my '73 FJ40 rebuild. I completely rebuilt the steering. It steers quite well but does feel a bit loose. In other words, it will wander a bit on the road without constantly correcting with the steering wheel. Is this typical? The rag joint itself seems like the source of play. I have tightened the center arm spring - not much difference. Thanks in advance. Mark

 

[pb4ugo]

Sounds like a typical caster angle issue.
Have you checked what the caster angle is?

 

[ukboneman]

I did a 4" lift and added 4 degree caster shims right off the bat. I have to remeasure the caster angle now that most of my body is on, weight wise. I know the shackle angles have improved a lot since adding all of the weight back. The wander is not terrible - just a bit annoying. I just found an extensive thread here on mud and there is obviously a lot of differing opinion. I rebuilt the steering box but did not measure backlash. I do wonder if that is the source of the loose feeling.

 

[POPO AGIE]

The FJ40 steering system is loose anyway and will wander, especially ruts in the interstate the trucks cause. Mine was loose when I drove it off the lot with 30 miles on it. It would wear me out. When I started working on the road it would take me 2 days to drive from SW, Wyoming to Portland, OR and be tired.

It improved when I learned to weld and moved the front shackles to rear of the front springs, but without power steering and the configuration it was still tiring on long drives. I even had two steering stabilizers mounted.

I have FJ70 tie rod, relay rod and tie rod ends with FJ70 hardware and convert to FJ80 power steering box.

 

[ukboneman]

The FJ40 steering system is loose anyway and will wander, especially ruts in the interstate the trucks cause. Mine was loose when I drove it off the lot with 30 miles on it. It would wear me out. When I started working on the road it would take me 2 days to drive from SW, Wyoming to Portland, OR and be tired.

It improved when I learned to weld and moved the front shackles to rear of the front springs, but without power steering and the configuration it was still tiring on long drives. I even had two steering stabilizers mounted.

I have FJ70 tie rod, relay rod and tie rod ends with FJ70 hardware and convert to FJ80 power steering box.

That’s the answer I was looking for I guess. This is not horrible and doesn’t feel like an alignment issue. I am going to remeasure the caster angle.

 

[B y r o n]

Since the front rebuild did you have the alignment checked?

 

[pb4ugo]

I run a 4" skyjacker lift and extended shackles and added 4* shims. Initially, my caster angle measured about 0. I then shortened my shackles, so I'm around 1+ caster . I'll likely be going to 6* in the near future. I doesn't really wander, but my steering wheel is a little sluggish on re-centering after a turn. Fyi, I am running power steering. Wandering, wheel correction, recentering the wheel is usually related to caster.

 

[pjohnson]

Also make sure your toe in is correct.
With a 4" inch lift, my bet is caster.
Did you put the shim in the correct direction?

 

[fyton2v]

Was surprised by how big of a difference shims made after installing a 2.5” lift. With M/T tires my truck doesn’t take much thought to keep a straight line. It’s not the same as a modern passenger vehicle, but not bad.

 

[sterling]

Was surprised by how big of a difference shims made after installing a 2.5” lift. With M/T tires my truck doesn’t take much thought to keep a straight line. It’s not the same as a modern passenger vehicle, but not bad.

This was my exact experience. Truck had an old 2.5 lift w/new BFG AT's and was all over the road, shims made a huge difference in correcting that.
Lots of positive change in my truck for a little $

 

[ukboneman]

thanks everyone. I did put the shim so that the thick part was pointing toward the drive shaft. I measured 1 deg caster angle, but how accurate is that? I measured the diff. pinion vs. the floor which is pretty flat. The skyjacker 4" lift is settling every time I take it out which I think is helping. I should get an alignment. I probably don't have any toe in, so I may adjust that. I have a lot of play in the rag joint itself, so that may be what I am feeling. Appreciate the input though.

 

[CruisinGA]

thanks everyone. I did put the shim so that the thick part was pointing toward the drive shaft.

thick pointing towards driveshaft is reducing caster. Sounds like you want it the other way

 

[pb4ugo]

The thick part of the shim should be towards the frt of the vehicle. Park on level ground and proper even tire pressure. Put angle finder on the edge of the bottom trunion bearing cap. Don't use the studs, nuts, or washers. Pretend my level is the angle finder. The top of axle needs to be rotated back 1 plus degrees. A little more is usually a little better. As I mentioned mines at about 1 degree and I'm going to try about 3*.

 

[ukboneman]

My bad, I did it a while ago and couldn't remember. I went and looked and the thin point of the shim is pointing towards the drive shaft. I have a 4" lift with longer shackles, so I installed them to point the diff. pinion more horizontal, as it was pointing skyward.

 

[pb4ugo]

My bad, I did it a while ago and couldn't remember. I went and looked and the thin point of the shim is pointing towards the drive shaft. I have a 4" lift with longer shackles, so I installed them to point the diff. pinion more horizontal, as it was pointing skyward.

I figured as much. If your shims were installed backwards it would be scary twitchy. Slight wandering would be non existent, it would be all over the place with minimal steering wheel input. You need to see what your caster angle is. Also check your toe in. You should be able to check these dimensions it yourself.