Does your steering wheel center itself?

[dpstark2]

I have a '67 Charger and a '72 Dart equipped identically as far as power steering. Both have Firm Feel stage 2 boxes and Saginaw pumps. I recently got the Dart together and aligned. Some of you may know the story- the entire drivetrain was proven in another Dart that was wrecked. Per Firm Feel, I asked the shop to set 3-4 degrees of positive caster. They set it in the middle and the alignment sheet looks great.

In my Charger, when I go around a corner, the wheel automatically comes back to within a few degrees of center and the car straightens out like a modern car. In my Dart, the wheel comes back to about 1/4 turn from center, leaving the car turning HEAVILY right or left. The same is true of a lane change at speed- the wheel basically stays where you leave it and the car wants to continue left or right. Frankly, it feels unsafe. Furthermore, If I turn the wheel about 1.5 turns either way (this is a tight, u-turn sort of situation), the wheel will not auto-center at all. There is a definite point in the steering where it goes from centering (back to a 1/4 turn of straight) to not centering at all.

The power steering pump definitely works. There is no noise or play in the suspension other than a little in the steering coupler that I still haven't repaired (this accounts for some play, but not the issue I'm seeing). I have had this entire drivetrain and suspension in another car and can't remember having this issue. I did lower the pump pressure quite a bit, but I can't decide if that's an issue since manual steering cars center pretty well too without pressure.

Is this an alignment issue? Could there be any other cause, like the pump? The shop's alignment sheet looks good, so before I go back and ask them to recheck it, I would like some outside information.

Thanks!

 

[dieseldazzle]

My 67 charger did this when I incorrectly adjusted the steering box, best I can tell you.

But I did see you cruising in Livermore by the vineyards in your 67 charger a few days ago. Rockin the beard like me.

 

[dpstark2]

What did you incorrectly adjust? The thrust on that top nut/screw? I don't think I touched that, but I may have. I know I tightened up the one in the Charger once.

 

[mr.belvedere]

memory steer from a stiff or worn ball joint(s)?

 

[dpstark2]

Interesting thought- the whole deal only has about 500 miles on it. All Moog parts, all new from Firm Feel. I don't remember anything feeling wrong, but I'll check.

 

[dieseldazzle]

I adjusted the screw on the top of the box with the car not running verus running. Made it feel notchy and not return to center.

 

[YY1]

Caster is the adjustment that helps center the wheel going forward (and also makes it turn hard to one lock going in reverse).

It's done at the upper control arrn eccentric bolts (on 66-70).

You can adjust the caster to correct the condition above.

...or should be able to, anyway.

 

[Coronet 14]

Is there any binding or rubbing in steering column. On my 72 Coronet I found the lockplate on the shaft was hitting the inside of the collar. The shaft was too far up. Fixed it now steering returns close to center.

 

[dpstark2]

There is definitely some stuff happening in the steering column. I haven't had a chance to disassemble it yet, but that's a good idea. The column has a Grant wheel on it, which is at least rubbing or binding slightly somewhere. And as I said, the coupler is completely shot. I hope to get into it today. Thanks for all the ideas.

 

[dpstark2]

I found the adjustment procedure for the sector shaft thrust screw in the FSM and it says to adjust 3/8-1/2 turn past zero lash, so it is a fairly tight setting to begin with. I have played with it from where it was originally, +/- about 1/2 turn and it doesn't change the problem.

There is also a note in the FSM about testing the box's internals. It says to turn the steering wheel one full turn L or R and apply torque to the sector shaft nut on the bottom where the pitman arm attaches. With the car running and wheels off the ground, the force to turn the shaft back through center should not exceed 20 ft-lbs. I did this test and I could barely get the shaft to turn with a long handled wrench. I'd estimate it took 50+ ft-lbs.

I then tried to steer the car at the wheels with my hands. It took just about all I could muster to turn the wheel from half right or left back through center. That doesn't seem right to me. According to what I've read, there is either a problem with a ball joint (or several) or a problem with the steering box internals. The power steering pump definitely works as turning the wheel with the car off and on the ground is much, much harder than with the motor running. Also, all of the above tests are much harder without the motor running, so the pump and box are assisting movement to some extent all around.

My Charger has the same setup. I put it in the air. Motor off, the sector shaft and tire can be steered with less force than the Dart- maybe 2/3 the force. Started the Charger and repeated the test. The sector shaft moves MUCH easier, and moving the tires by hand takes very little force by comparison. Furthermore, once you start turning a tire by hand, the force required drops and it seems to help you back to center. When you stop turning the tire, it continues to move a few degrees, but then stops. The Dart stops immediately with no noticeable difference in starting and moving force.

At this point, I need to start separating the tie rods and seeing where the resistance is coming from. Whatever it is, it's equal in both directions. I have a sneaking suspicion that the box is messed up, somehow. There is no indication from normal driving or inspection of any other suspension related issues.

Any thoughts?

 

[dpstark2]

I separated all the linkage and centered the steering shaft in the column, and the resistance is definitely coming from the steering box. I also put the power steering pressure back to stock. Nothing helped. I talked to Dick at FFI (he's a good guy) and he was pretty convinced the sector shaft had been adjusted too tight. I ended up backing the screw off 2.5 turns to get to the point where I couldn't feel any resistance being created by the mesh of the teeth in the box. This got me to a point where the car centers itself to within about 1/8th turn of the wheel. My Charger is still better, so I wonder if I can get more caster out of the setup.

What is so curious to me is how this happened, and I only have one theory. When I had it aligned, the tech commented that my box was quite worn out. I didn't agree, but I wonder if he took it upon himself to crank down that screw. It would explain a lot. I still wish it centered itself a little more.

 

[dieseldazzle]

I separated all the linkage and centered the steering shaft in the column, and the resistance is definitely coming from the steering box. I also put the power steering pressure back to stock. Nothing helped. I talked to Dick at FFI (he's a good guy) and he was pretty convinced the sector shaft had been adjusted too tight. I ended up backing the screw off 2.5 turns to get to the point where I couldn't feel any resistance being created by the mesh of the teeth in the box. This got me to a point where the car centers itself to within about 1/8th turn of the wheel. My Charger is still better, so I wonder if I can get more caster out of the setup.

What is so curious to me is how this happened, and I only have one theory. When I had it aligned, the tech commented that my box was quite worn out. I didn't agree, but I wonder if he took it upon himself to crank down that screw. It would explain a lot. I still wish it centered itself a little more.

Again,
I experienced the same thing when tampering with my sector shaft screw. It took quite the fiddling with to get it correct. Engine running with my wheels off the ground i got it back after tampering with it. My box was worn out and eventually replaced but at one ppint it would stay pinned in either direction it was steered after a turn.

 

[dpstark2]

I've had the Dart back to two different shops. Alignment checks out. The sector adjustment has no effect other than to make the box sloppy. I'm back to thinking it's the box, so I'm going to swap in an unknown box for comparison. Both shops that have looked at the car suggested the box was the issue too. Anyway- maybe the box is bad. Just FYI...

 

[dpstark2]

I swapped in a spare unknown box I grabbed at a swap meet last night. Before putting the box in, I felt the resistance on the worm gear of both boxes. There was slightly more resistance in the FFI box, but nothing truly significant. I could not turn either sector shaft by hand. Maybe if I had a spare pitman arm, but not by hand... So they both seemed roughly equivalent. Note the FFI box had zero backlash, and the spare box had less than one spline of play. I swapped in the spare box.

Before going any farther, I grabbed the driver's side wheel and swung it lock to lock by hand. It was much, much easier to move than with the FFI box. However, the box was dry. I need to repeat this with the box bled. I was encouraged at this point.

So I bled the box, filled the reservoir, took it around the block, filled the reservoir, repeated. The box is so loose and over boosted it was hard to tell what the difference was. I may be able to tighten up the adjustment, but I haven't gotten there yet.

This morning, I drove it to work. Bottom line: It is somewhere between zero and ever so slightly better. 1/8th turn from center while driving still leaves the car going that direction. Coming out of turns, it comes back to 1/4-1/8th of a turn from center. It is nowhere near how my Charger behaves. Given the choice, I'd take the FFI box.

I have no idea where to go from here. Any thoughts are appreciated.

 

[AR67GTX]

I would be suspicious of the caster. I didn't see above where you discussed any alignment settings so I assume you are completely sure where they are right now. These cars were originally designed for slight positive camber and minimal caster for old bias ply tires. Radial settings can be a problem especially with 50 year old chassis designs and production tolerances. I just rebuilt my whole front end and put off set bushings in my rear upper control arm points in hopes of getting a bit more caster. However, I set my ride height a little higher than it was before (but not drag racer high) and used poly bushings on the strut rods. I think those last two items negated my caster efforts as best I could get was 1 deg neg caster with 1/16 deg neg camber.

From my experience, I think it would be real easy to end up with zero to positive caster and steering that is a bit squirrely and doesn't return to center. I suspect that just cranking up the ride height might do it but it could be the poly bushings on the strut rod were the major contributor.

However, even with just 1 deg neg caster my car drives great. Steering is tight and solid and returns to center just fine. I have an older Steer and Gear firm feel box (PS) in it.

 

[dpstark2]

The car has Firm Feel strut rods, torsion bars, upper control arms, pivot pins, urethane LCA bushings, the lower control arms are boxed, etc. In my first post, you'll see that according to FFI, they said to have caster set at 3-4 degrees and all other settings in the stock range. That is what I asked for. Both shops have the caster set at 3.5-4 degrees positive. Unless I'm totally mistaken (and that happens), positive caster is what is wanted here- not negative. The stock specs for the car are I think listed at -.5 to 1.3 caster, and the FFI UCAs are supposed to add 2 degrees to that range (in the positive direction). The fact that the shop that did the original alignment said they had trouble getting "as little as" 3.5 degrees is still a little troubling to me.

I don't know what the camber was set at it, but it's on all the print outs. I will look later.

I swapped the FFI box back in last night. It's the same as it used to be and I can confirm (aside from boost and looseness) it's no different than my spare box. I also double checked play at every joint, that the LCAs weren't moving, that everything moved freely, etc. At this point, I think I need to take it to a specialist to help sort out this issue. I'm at a loss.

 

[AR67GTX]

Yes, you are correct. Coming down off meds from Knee surgery. Probably should stay off the computer.

Pos caster of 3.5 degrees is a solid reading though. It should easily self-center with that - if nothing else were wrong.

After this I think I'll just cruise forums and refrain from posting for awhile.

 

[Darthomas]

There were once offset upper control arm bushings for this application to help this, in addition to not being able to get enough camber adjustment, but
probably not anymore.
Needs more caster probably, but insufficient toe-in can contribute quite a bit to this problem.

 

[Ron H]

I recently had the castor adj at alignment shop to near max attainable on my 63 Fury. This is after putting on 235 radials on 15" wheels post disk brake conversion. Car always had some wheel recovery issue even before the changes. I think it was someone cranking on the box. As it is the castor adj seemed to help a lot.