Just finished replacing all the steering and ball joints in my 71 Cutlass sat. drove alot better, but still had the loose no road feel to it, Was talking with a local guy that does the alignments on alot of the race cars in the area yesterday, he said that until I think he said it was the late 70's the factory aligned cars with neg caster, as people wanted to be able to steer with one finger, and they used bias ply tires, He told me to bring the car to his shop today and he would align it, Picked it up this afternoon, what a difference. He said everything was pretty close, but he put postive caster in it. Feels like a new car now, instead of the cars I drove back in the 70's.

 

Nice, I also just replaced everything and had the wheels aligned. It is a nice felling.

 

That is correct. I remember reading an article about one of the mid-70s H/Os (when the cars were new) and the alignment was changed as you describe. It made a significant difference.

 

Here's some more info on the subject

http://www.ozebiz.com.au/racetech/theory/align.html

 

Must be the reason the Moog upper control arm shafts are called "problem solvers", as they "provides additional positive camber adjustment"

Just how much extra go you need? Do the alignment guys "know" what to set it at or do they just do what was recommended in 1972?
I need to have an alignment after I redo the front end - I want it to be aligned better...

 

When I orginally talked with the guy about my alignment, he said most shops will align a vehicle according to the manufacture specs. He said he figures his alignments based on the vehicle tire size and what the intended purpose of the vehicle is. also what the person wants as far as steering effort etc.. He asked me if I was going to be leaving the tires that are on the car on it, as he figures all that in. How he does it he didn't say. I will see if I can pick his brain somemore, as he has done alot of work for me in the past on both our street and race cars.

 

Post the specs.

 

That's an Australian website. Don't cars run the other way in the southern hemisphere or something?

Seriously, the article I remember (and keep in mind this was over 30 years ago) said that they used something like 4 deg positive caster on that H/O.

 

Boy, that would sure be nice - please do if you can get them. We seem to only have preprogrammed goons running the alignment racks around here in the bigger shops. I need to find a small place where the guys really know about old cars...

Okay, so I hear +4*caster, any others?

 

tow and camber is what will wear the tires. caster, where ever it is won't hurt the tire but is mostly to do with handling. this is the best explanation i have found. it is from the 4 wheeler ATV stuff i do.

Caster is the amount of angle that the spindle has in relation to the vertical centerline of the wheel.
If the upper ball joint is farther forward than the lower ball joint, it is said to have negative caster. If the
upper ball joint is farther to the back than the lower ball joint, it is said to have positive caster. The greater
the amount of positive caster, the more stable the ATV will be at speed. The less positive caster it has, the
easier it will steer and the quicker it will turn. As the spindle is laid back, the tire has to lay over more
when the front tires are turned. This adds stability. If there is not much angle, the wheel will turn more

easily, making it quicker and easier to turn.

so keep in mind that the if you like to drive on curvy roads, it will respond better with the old settings. with these old cars it is very unlikely that you will notice much difference in the turning ability because of the weight of them in comparison to the tires. if you just drive then the newer settings are the way to go. with the newer settings i would think about going to the quicker steering ratio steering box. coming from my ATV experience i would think he is setting them around 4 to 6 degrees positive, i sure would not think he is going more than 6.

 

sorry, i did not see the link above. it is just as good as what i had.

 

I just got done talking with him, He said he set mine at 2 degrees postive, because I am running 255-35ZR tires on mine. And with that wide of a tire and small sidewall that much more would cause the steering wheel to kick when hitting a bump. He did say that with a standard tire 3 to 5 degrees would more than likely be good. But it would be the drivers preference, It will not affect tire wear, if it was to hard to steer for the particular driver take some out, or if it is to loose to add some. All that you have to be carful of is to keep both sides equal, and to not go to far or the wheel will kick when hitting bumps. The wider the tire and smaller the sidewall, the less caster that is needed.

 

I've got an old car magazine somewhere with an article on this. I don't remember the number they recommended but will see if I can dig it out.
John

 

So I think 3 or 4*+ would do me well. I will specify that at my next alignment and see if the tech's head explodes. If so i will just go elsewhere...

 

From my reading you cannot get more than 2 degrees positive caster with stock upper control arms. Can anyone confirm this?

I'm wonderign if the offset upper control arms shafts would allow more caster, or only fix the camber for sagging frames...

 

Ben, I put those offset shafts on my 1970 many years ago. It does allow for more shims to be put in each bolt where the upper A-arm attaches to the frame. I need to brush up on what changes the caster, so I don't know if it helps that or not. John

 

Yes the offset control arm shafts helps both camber and caster. The camber is adjusted first then the caster is adusted by moving shims from the front bolt on the control arm shaft to the rear, this increases caster to positive readings , by moving shims from the rear to the front you decrease caster to the negative . Caster should be as close possible in readings from side to side. A difference of more than 1 degree will cause a pull or lead to the side of the car with the caster reading closest to the negative side.

 

I just had my front end alignment done. I asked the technician if he could put a little more + caster in the front end to eliminate the "loose" road feel. After the alignment was done, he said he tried but could only get to a - 1/4* and -1/2* respectively. He said I would need to get new upper control arms in order to gain the + 3-5* range I was looking for.

BTW I have a 70 Cutlass S Holiday Coupe. The car still handles markedly better with the adjustments he did make.

 

This is a big help. I was thinking of getting mine realigned and I will definitely ask them to align it to those specs.