I have been adjusting my steering. So far I had too much play in it, making for an unstable feeling and difficulties setting alignment. Always had a problem with the wheel returning at the last 1/4 turn of the steering wheel.

I adjusted the steering so that I could just feel the pitman arm move when someone slightly turned the steering wheel.

Now when taking a 90° the wheel returns as before but the last 1/4 turn it doesn't return by itself. I also have the same thing when driving at speed. Otherwise it's great.

Setting the play looser creates greater amount of movement at the wheel doesn't seem to improve something.

I already have 4.5° of caster dialed in, with VBP offset trailing arms, so not much to be had there.

Anything else that can cause this ? Or is this just the way things are.

 

Also a '79, with stock steering. Did not have this issue.

 

With the wheels up, does the gear operation seem smooth? Any binding?
Assuming Power steering, any issues with the ram?

Is steering equal from lock to lock? VERY important for centering

Got enough air in the tires? Try greasing all the joints?

Just looking at simple fixes.....

 

Adjusting only the 'lash screw' rarely brings any satisfactory results.
You must pull the box and set up the worm bearing first.
At that point, you might as well rebuild it.

 

worn/old bushings, bad rag joint, etc,... could cause loose steering too. Lots of possible things to run down unfortunately.

 

My car had zero return. I could go through a roundabout with my hand off the wheel. Took it to a dealership that still works on our cars and they just did an alignment and its a 1000 times better.

 

Couple of things, all new suspension parts. (body off resto).
It seems to turn equal amounts left to right. Power steering pump is new, valve is rebuilt as is the steering ram cilinder. New lines, alignment..basically everything.
Gear is not rebuilt though. When I had it out I set the lash with the big nut on the box.

Maybe it's me. I've always driven rack and pinion cars and they have great returnability.

 

Meanwhile I reset lash on the gear looser again and went for a drive. Now it does seem to return well at speed but only when turning left. When turning right it's the s

 

Just went under the car and had my son turn the wheel. Now there is some movement at the stud in the power steering valve. Not sure if it's supposed to be like that.
This was with the engine off. So maybe, the play is gone when the engine is running

I'm I right about this or is my power valve shot or so ?

 

Ball stud will move when the engine is off. You need to check with the engine running. I agree with Peterbilt both adjustments on the steering box need to be set up correctly.

 

steeringsystemcenter.. - Jim Shea's Steering Papers
jimshea.corvettefaq.com/.../steeringsystemcenteringc3pddfrev28jl2009 1.pdf‎
(CORVETTE 1963-82, CAMARO/FIREBIRD 1967-69, AND NOVA, SKYLARK, ... vehicles; C2/C3 Corvettes, First Generation F-Cars (1967-69), X-Cars (1968-74), and .... such that it will install on any of the serrations of a later gear with a flat.

Have a read of this excellent paper by Jim Shea and you can ensure that the steering is correctly centred. The steering box is designed to have a slight tight spot at the straight ahead position so getting the steering correctly centred and the steering box lash adjusted correctly is important, too tight and you risk damaging the steering box internal components as well as making the steering feel wrong. Too loose and the steering tends to wander too easily at the straight ahead position as well as having excessive play when turning.

 

The condition is called Traming or Tramlining... It starts and ends with the fact that your, any, C3 has very little caster. These cars were designed for big motors and big power, they are intended to be driven as much with the gas peddle as much as the steering wheel. If you have ever driven any performance car designed in the 60's, say a Shelby Cobra you will find the same condition. Do not think that a C3 will ever drive like a Caddy, if that is what you want, trade it now... They dive into turns because the driver points the front and then throttles it out. Watch the chase scene in Bullet in slow motion, THAT is how you drive a 'pusher'.

Recirculating ball steering boxes are relics of a by gone era, If you have deep pockets, consider a rack and pinion set up.

You can help the problem by dumping the 15's and putting a set of 16's with modern tires on it like a set of Pro Comps. Don't go much bigger, it will only make the condition worse. Avoid 'run flats' with stiff side walls, and dump the big blockey tread patterns. Have your alignment shop add 3 deg, of caster and set the toe to 1/16 in. Most tuner shops will be happy to work with you in changing the set-up. You will violate the spirit of your Vette but it will calm thing down for you.

People forget that this is basically a truck chassis. Don't judge the platform by modern standards, you will be very discouraged.

 

While I am in basic agreement with the points in your post, I would like to add three points:

1) The OP states that his car has 4.5 degrees caster. This is enough to eliminate the Tramline phenomenon you refer to.
2) Tires - A C3 needs performance radial tires. It is very difficult to find these in 15 OR 16 inch diameters. If you wish to keep the stock approx. 27 inch tire height, you will need a 17 inch wheel with a 50 aspect ratio tire or an 18 inch wheel with a 40 or 45 aspect ratio.
3) Steering Systems - There are currently 3 basic choices. A) The R&P system you refer to, B) A stock system with a professionally rebuilt steering box such as that done by Gary Ramadei, or C) a Borgeson/Jeep replacement box. Each of these three systems has its proponents and each seems to bring satisfactory results. I think the choice is a personal one

Given the time and money the OP has put into his build, I would probably recommend the professionally rebuilt box, followed by the Borgeson with the R&P coming in last. This choice is not based on the merits of the systems, but on the amount of amount of disruption involved. The OP has recently completed his car and does not need the hassle of another teardown and rebuild before he can enjoy it.

 

I did not pick up on the fact that the OP had stated the caster had been updated, my bad...

I have fully updated my 78 SA. I believe though there is always room for improvement, that it is about the best its going to get. Now, well into the 2016 driving season I find myself reuniting with how she drives, and almost preferring it on the back roads.

One last thing, I live in The ever cash strapped Soviet Peoples Republic of New York, our roads absolutely stink. On a recent trip to Penn, I found that driving on real, maintained roads goes a long way to the C3's stability.

 

Coming back to this : I disconnected the steering column from the box and measured rotating torque. I then disconnected the pitman arm from the rack and reconnected the column to the box and measured torque.

I reset everything with 12 inch/pounds of torque.

Now it seems to work out fine, but unfortunately it seems to return to center while taking a left hand turn fine, but in a right hand turn it doesn't completly return.

But at least it's a lot better than what it was.