She's the type of girl that likes to wander round

[Sac '68 sport]

The bronco not the ol'lady...
Background:
It has a strange Power steering set up that a PO put in out of an old Mercury car. It puts the pitman at a bit of a strange angle, ie the shaft is cocked toward the back a little so they could get the steering shaft to clear the frame. I would have changed it but they cut into the frame and boxed it in so now that it's all restored it would not be worth trying to change.

I previously had an old school stiff as a board, JD dual shock, stock height set up. No issues at all other than it road like crap.

When I did my recent resto I ditched the JD shocks and went with 2.5 inch coils I picked up 2nd hand off a guy from the NorCal Broncos page (I think they are from Jeff's as they are not variable rate, but they are fairly soft and ride nice) and Rancho RS9000's. I used the same C bushings that came with the old Duff kit and added a WH extended track bar. I still need to get an indexed drop pitman arm as the one I have now I can turn tighter going left than right. However because of the way the PS box is cocked back I'm not going to get much drop out of it over what I have on there now.

With the new springs it rides softer, but it's all over the place now. Every bump in the road is like a roller coaster. You really got to drive it to keep it in it's lane.

Would 7deg. bushings help? Any other suggestions?

 

[Apogee]

Post up a picture of your steering linkage relative to the track bar, as well as some of your power steering box setup since it sounds relatively unique. It sounds like you just have a bad case of bump steer, so while higher degree c-bushings and the associated caster they provide may help your overall handling, it won't address the bump steer issue.

 

[Rustytruck]

First thing to check is your toe in. if you have larger than stock tires you want 3/16" to 1/4" at the outside tire dimension.
http://www.bcbroncos.com/alignment.pdf

 

[DuctTape]

Here's what I've learned it could be from my own battles against wandering:

Caster
Toe-in
Steering box bad
Steering box not centered
Drag link/trac bar not parallel
Bad bushings
Bad ball joints
Non-symmetric coil springs
Tire pressure
Tire wear patterns

You can test each of these potential failure points. I suggest doing them like so:

1. Check for bump steer
2. Check bushings and ball joints
3. Re-center steering box
4. Take rig to alignment shop and get caster/camber/toe readings
5. Evaluate steering box

1. The best tip I've seen in evaluating drag link/trac bar is to jump up and down on the front bumper. If the steering wheel moves then bump steer is at least one if your problems. There are various solutions for fixing these angles, from drop pitman arms, trac bar drop bracket, and trac bar riser. Make sure your rig's axle is centered under the body.

2. Standard home test for bushings / ball joints is to have a helper move the wheel back and forth while you look for slop.

3. With tires pointed straight ahead, unhook pitman arm. Rotate steering wheel to far right, put a piece of tape at 12:00. Rotate steering wheel to far left, put a piece if tape at 12:00. Put a third piece of tape in between those two. Count total turns and make sure third piece of tape is at 12:00 (or 6:00 depending on which side of circle you split the l/r tape). Triple check by counting turns from third tape at center to lock both ways. Reattach pitman arm.

4. If none of the above fixes problem, spend the money on test so you know what's wrong - chasing caster can get pricey. Toe-in fix is easy, caster can be easy fix with c-bushings but c-bushings won't always fix it. If you get to this point come back to the boards (there is a recent thread discussing caster fixes ad naseum).

5. 5 might be before 4 if you have an easy way to diagnose the box. I bought a new box right after I got my rig so it was never something I had to chase.

Good luck! Hopefully it is one of the easy fixes.

 

[Sac '68 sport]

First thing to check is your toe in. if you have larger than stock tires you want 3/16" to 1/4" at the outside tire dimension.
http://www.bcbroncos.com/alignment.pdf

For this measurement does it matter how exact I get the measurement in the "front" vs. "back"? Ie. do I need to use a level vertically along the tire to make sure I'm getting exactly the front and then 180 deg. when I roll it around or can I approximate it?

 

[Sac '68 sport]

No slop in steering box, it's fairly new and all but the C bushings are new poly. It has very low mileage 32 x11.50's BFG AT's on it and are the same tires I had prior to the 2.5 inch springs.
I know for sure the box is not centered. I still have to get a fully indexed pitman arm to do that. Stupid key ways...I don't think that's what is causing this though.
It's still the Kingpin D-30. It works and everything was still nice and tight on it when I pulled it off checked it all out. I don't wheel it so I see no need to replace it with a 44.

I'll jump on the bumper to look for bump steer and check the toe using the link from BC.

When I hit larger bumps or like when backing out of the drive and the front tires come off the curb and the suspension compresses it feels like the whole front end dips in an arch to the side instead of just going straight up and down. Body stays flat but it shifts toward the side as it compresses. The wheel doesn't jerk on me or anything.

 

[Rustytruck]

For this measurement does it matter how exact I get the measurement in the "front" vs. "back"? Ie. do I need to use a level vertically along the tire to make sure I'm getting exactly the front and then 180 deg. when I roll it around or can I approximate it?

I rais up the tire from the ground and put a cinder block just in front of the tire and spin the tire. i use an awl to sctatch a line in the tread. then I put the tires back on the ground and make sure they are pointing straight ahead. then at mid heigth of the tire I measure from line to line in the front and measure line to line in the back. I compair the 2 measurements. you want the rear wider than the front by 3/16 to 1/4 inch if your running oversize tires.

 

[Jebus]

i use an awl to sctatch a line in the tread.

Use white rattlecan paint first and then scratch your line.
Makes it easy to measure toe in and wears off in the first mile...

 

[DanHall]

Use white rattlecan paint first and then scratch your line.
Makes it easy to measure toe in and wears off in the first mile...

Y'all are fancy, I used two pieces of tape and a marker to draw a reference point on each piece of tape. Had the guys at the alignment shop surprised when it was in spec before they touched it.

 

[broncnaz]

As others have said check the toe in. also tire pressure plays a big role you may want to play around with that. You dont seem to have bump steer so the indexed pitman arm may be a waste of money. Also new poly bushing are fine but what degree c bushings did you get?
Lots of little things that can be done or checked before you pour more money into things that may not work.

 

[DuctTape]

No slop in steering box, it's fairly new and all but the C bushings are new poly. It has very low mileage 32 x11.50's BFG AT's on it and are the same tires I had prior to the 2.5 inch springs.
I know for sure the box is not centered. I still have to get a fully indexed pitman arm to do that. Stupid key ways...I don't think that's what is causing this though.
It's still the Kingpin D-30. It works and everything was still nice and tight on it when I pulled it off checked it all out. I don't wheel it so I see no need to replace it with a 44.

I'll jump on the bumper to look for bump steer and check the toe using the link from BC.

When I hit larger bumps or like when backing out of the drive and the front tires come off the curb and the suspension compresses it feels like the whole front end dips in an arch to the side instead of just going straight up and down. Body stays flat but it shifts toward the side as it compresses. The wheel doesn't jerk on me or anything.

Adjusting my steering box was a much bigger improvement than I suspected. I thought I had it centered but I had used two tape mark method vs three. When I re-centered I got significant reduction in wandering. I think you can address the keyed issue with a small triangle file.

On the side shift when compressing - is the axle centered under the body? If a suspension lift was done without mods to trac bar there is a good chance your axle is not centered under the body - that could be it.

 

[DuctTape]

Use white rattlecan paint first and then scratch your line.
Makes it easy to measure toe in and wears off in the first mile...

That's why I live this site. Common sense tips. This is a good one.

 

[Sac '68 sport]

So it looks like my toe is off by quite a bit. Finally got a couple minutes to go out and do a quick measurement. It's 9/16 wider in the front than the back. I just used the tape method so I'll confirm that when I have a little more time.

The axle does appear to be centered under the body from looking at it but I've never measured it. I got a longer track bar when I did the lift but I eyeballed the length. I'll measure that up too, hopefully tonight.

 

[hammer189]

I used duct tape, a black marker and a tape measure. Measured height of mRks in front. About 15" from floor. Measured width between marks and made notes. Rolled backward till marks were about 15" off of floor and measured width again. Took about 4 or 5 rolls to get it within 1/4". Initially i was way off. Good luck

 

[Sac '68 sport]

Tie rods ends are stuck in the sleeve. That thing is jammed up good.
Hit it with PB blaster and a propane torch and tried turning it with a pipe wrench and it's a no go.
Any ideas?

 

[Justafordguy]

Let the blaster soak a few days.

 

[Timmy390]

Let the blaster soak a few days.

X2 and reapply every 12 hours or so.

Tim

 

[Sac '68 sport]

Soaked it a few times over night and it came loose no problem this afternoon. That stuff is magic!
Adjusted the toe and it's like a whole new rig. I can't believe how much difference it made. Also tightened up the nut that attaches the draglink to the pitman as it was a little loose. I'll still have to do the pitman and center everything but at least I feel safe driving over 45 now.

Thanks for all the tips everyone.