Steering does not return to center when turning

[phantom]

Hi.
I have a problem with the steering on my 68. The box is rebuilt and i have fitted a Hydratech hydraulic brake booster. The whole car is rebuilt and the system (and car) have only travelled like 160 miles all together so far.

Problem is that the steering wheel does not at all turn back to center when i turn either way while driving. At first i had some issues with air in the system, as the steering wheel would "nudge" from time to time. Think i have bled it properly now. Had it to an alignment shop the other day, and now the caster is 3.45 on one side and 3.50 on the other. Should be enough. Then i tried to go full caster by adjusting the rear mounts of the upper control arms fully inwards, but it didnt help.

Can it be trapped air still in the system? Bad pump? Anything on the rebuilt box pulled to tight?

Need some help here, as my car wont pass inspection if this is not resolved.  

BTW, the instructions on the booster system says to allow 500 miles of driving to let the system "settle", to get all the microbubbles out. Seems like a lot  

[green69rt]

If you have the FSM there is a procedure for adjusting the centering action of the steering wheel.  The top fitting on the box needs to be loosened and tapped fore and aft to get the wheel to stay centered.  Not a big deal but you probably need to do it.  Got the FSM??

[phantom]

I dont have it. Tried some more today, tried turning the wheels from side to side with my hands while the car was on stands with the engine off, no problem. So no binding parts in the suspension. Bled once more. I got a tip from the guy who rebuilt the box, to loosen the screw on the sector shaft, as it was maybe to snug. Anyone try this? Do i loosen the nut and turn the inner screw 1/4 turn and then tighten?

[John_Kunkel]

To check the valve adjustment, jack the front wheels clear of the ground and follow this procedure:

[Mike DC]

The self-centering of modern vehicle steering (when you're rolling) happens because of the wheel alignment, not the steering hardware itself.  I assume you're aware of that. 

[phantom]

The steering wheel does not move at all when i start it with wheels jacked up. Should be no need for adjustment of valve body if i understand correctly?

Mike, i had my car to the alignment shop, and have every measurements in the green, with the caster 3,5 on each side.

How much resistance should there be when i turn the wheel, engine off, on stands?
Worth mentioning that i have Magnumforce 2" dropspindles too, but dont know how that could affect anything.  

Thanks for the inputs guys, really appreciate all help i can get

[Mike DC]

       

Mike, i had my car to the alignment shop, and have every measurements in the green, with the caster 3,5 on each side.

Okay that base is covered.

I don't see any relevance to drop spindles either.   


Definitely do the FSM adjustment on the steering box tightness.  It's pretty simple.     

[John_Kunkel]

Shoulda mentioned the drop spindles right off, changing the point at which the spindle intersects the knuckle changes the geometry so you might need a lot more caster. 

[JR]

I agree with John. Some adjustable UCAs maybe in your future.

[Mike DC]

                               

Rethinking this, yeah, it may indeed be the drop spindles.  

I usually don't think of drop spindles "changing" the geometry but rather just moving it within the original range of motion.  But with the caster varying across the range of OEM movement . . . drop spindles would change the static caster situation.

I have never been a fan of drop spindles myself.  They aren't terrible but IMO it's better to just use the torsion bar adjuster.


Was the alignment done before or after the drop spindles went on?

[phantom]

The dropspindles came with the Wilwood brakes, as a kit, sold by Magnumforce. The alignment was done after.


I disconnected the steering linkage from the pitman arm yesterday. The pitman is also new, Moog i think. It was lacking a grease nipple i remember, when i installed it (driven like 160 miles to this day after finished build). But i forgot about this, and never greased it up myself. I know they come with grease from factory. I dont know how much resistance there should be from a new ball joint, but this one i couldnt turn at all. I can move it side to side, but it takes some strenghts in my fingers to move it. So i fitted a grease nipple, used a grease pump to fill all ball joints in the steering, locked two nuts together and rotated it for like two minutes. The ball joint turns easier now.

I was hoping this could be some of the issue, but now i may have to buy new original spindles, if you think those are the problem  

[Mike DC]

                       
The alignment has 3 degrees of negative caster and it was done after the drop spindles went on?  That leans my suspicion back away from the drop spindles.  


Can you describe the problem any more?  When you turn the wheel and it "doesn't go back to center" . . . do you mean it doesn't do it by itself when you let go, but it easily goes back to center from hand inputs?  Or do you mean it's easier to pull the steering direction away from center, and then it puts up more resistance when you try to move it back (as in, more than the resistance when you were moving it away from center)?  Is the problem the same in both directions, occurring after either a left or right hand turn?
       

[phantom]

3,5 positive on each side, yes

Ok, to the problem: When i drive, and turn the wheel to the left, say 1/2 turn, and let go, the steering wheel stays there, and i have to by hand turn it back to center. Both sides, but it has a tendency to want to come back to center after turning right. Left side, nothing. Havent tried with higher speeds, just around my block.

Disconnected all of the steering linkage today and turned each wheel back and forth to feel for binding in the ball joints. The ends of the tie rods are a little "slow", but i can easily shift them in every direction.

Then i tried to push the pitman arm back and forth. Might be my imagination, but it feels heavier around center. This was with the engine off.   

[Mike DC]

 
Man, that still does sound like a lack of caster.  Is there any way the alignment could have been in error?  Did you change the 'rake' of the car to make it more nosed-down after the alignment was done (bigger rear tires, etc)?  

That wandering steering (like a little kid's tricycle that has the fork & handlebars mounted in a straight-up vertical head tube) was the normal state of muscle cars from the factory.  They used to build cars that way to cut down the arm effort for manual steering.  The modern trend of major-league caster angles only came into fashion once every car heavier than a VW Beetle was getting built with power steering by default.  


BTW, even 3.5 degrees of caster is not that much compared to some modern sporty cars.  It's about all these cars can handle because of some other factors with the front end.        

[JR]

Agreed with Mike.

Again, check out the SPC fully adjustable UCAs. I've been running them for a couple of years now. They allow for stupid amounts of caster without compromising camber or toe.

Heres what they look like.

[phantom]

The alignment was done 4 weeks ago, so pretty fresh. This car comes out of a 5 year build, the whole car has travelled like 160 miles all together, mostly for testing. Took it to the alignment shop prior to inspection to get the car registered. So, all of the parts on the car, steering, suspension is all new. Those 160 miles were done on my own garage-alignment.

So, no altering of rake or anything after alignment.

That being said, i disconnected the idler arm yesterday, and felt for binding. Noticed it had play up and down, turns out i didnt read the instructions and shimmed it underneath. It came with a shim washer. Plus, the sleeve inside was super tight. Had to put it in a vice an hand force it around, after filling it with grease. Doing this maybe helped a bit, plus i was able to get another degree caster on each side. Took it for a test drive, and sure enough the steering came bak from a right turn just fine. left turn is still slow, but if i help it on the way, it too comes along, but slooowly.

Havent touched the steeringbox yet, the steering wheel doesnt pull at any direction when i start it with the wheels lifted.
I am not 100% satisfied, but its going in the right direction at least.

JR, those look neat. I'll definately consider those