Torqued Off

So, drove the car a couple hundred miles this weekend. Pennyslvania roads can be full of ruts, holes and general lack of level, so it was hard to be sure, but there is a consistent pull to the right when hands off. Even when on the left lane of a two lane road where the road clearly banks to the left, within a few seconds of hands off, the car is going right. And I feel like I am holding left wheel most of the time to go straight and the steering wheels is definitely turned off center to the left. It seemed to pull right at steady state speeds. Acceleration never pushed the car left or right. Braking is straight, and my car is manual steering, so not power steering issue.

Any advice on what I should do? I really am done with taking cars to professionals, and want to learn and get into this alignment science so I can make logical tweaks. Otherwise, the car handled very well in the turns, and it felt good. I can feel the slightly higher caster settings with the manual steering, but still no issue for me.

I was against the idea of cross caster that I hear about to supposedly correct for road crowns, but what I got was actually 2.45 on left, and 2.75 on right, which from what I understand would be opposite of what I would want IF I did accept cross caster, i.e. the right should be higher than left......could this be my pulling right issue? Or is it toe, or camber.

Welcome any comments.

ignatz

Very likely it is caster and pretty simple to fix. I have some notes on which way to move the shims in my service manual but before I take a look somebody will probably chime in with same advice or will disagree vehemently!

leadfoot4

Generally, you run with a little more caster on the right (passenger) side of the car, to account for road crown. Since it pulls too far right for your liking, I would think there a few things you could try. First, verify the tire pressures. Secondly, you might have a little "radial tire pull". If your rear tires are the same size as the front, you could try a front to rear swap, and see what happens. If the rears are different, you could swap the fronts, side to side. Finally, you could take a little caster out of the right side, but if you choose to do it at home, be aware that it will affect both your camber as well as your toe-in.

v2racing

I set my caster the same left to right. If I let go of the steering wheel on regular 2 lane roads with a crown, it will drift to the right, although I don't feel it pulling to the right when holding the wheel. As I am not autocrossing or tracking the car right now and most of my driving is on these 2 lane roads, I'm considering adding a little castor to the right side.

Mike

ignatz

From my service manual, "the transfer of one 1/32" shim to the front bolt from the rear bolt will decrease positive caster by 1/2 degree".

I wouldn't get too excited about mucking up your other settings big time for minor changes to caster. The control arm response to the shim adjustment is to move the ball joint along an arc of a circle horizontal to the road. So the movement of the upper ball joint is a small change in the distance to the car centerline, for instance. That will pull or push the wheel in or out a bit but not by much. The lower a-arm doesn't change at all and neither do the tie rods so any change in toe is very second order.

So again from the service manual: "a 1/32" shim at each location will change camber 1/6 degree". And you're not doing that.

Plus this is a very easy thing to try out and easy to undo. And if it makes things worse, go back to where you were, and then try it the other way. Nothing much to lose.

Torqued Off

I appreciate feedback. My Post #21, after my couple hundred mile drive, I made an error. I stated I had more castor on right,.....actually have 2.74 on left, 2.47 on right, i.e. more castor on left.....so I am thinking this could be the problem. Anyways, couple comments in response to those who have posted so far:

- My tire pressures are all at 32 PSI, and using BF Goodrich Radial TA 255/60/R15 all the way around.
- There are no 1/32 inch shims installed on my control arms, so I have room to tweek some small changes, the attached pictures of where it is right now on left and right sides. I would like to try to make a small adjustment and see if can fix the right turning tendency. And I have lots of 1/32 inch shims to go slowly. Any recommendations.

- LEFT SIDE FRONT - ONE 1/8, TWO 1/16 LEFT SIDE REAR - THREE 1/8


RIGHT SIDE FRONT - TWO 1/8, RIGHT SIDE REAR - TWO 1/8, ONE 1/16



Ultimately, I am shopping for the best home DIY alignment tools....thinking of Quick Trick setup. My main goal now is to slowly make corrections, see if I can get the car to stop drifting right,......and then carefully check alignment numbers. I know I am very close. I am thinking if I reduced each of the four points by 1/32 inch as required, I could get the spreader bar installed,.....AND maybe getting back to zero camber.???? How this affects TOW, I don't know.

Another issue, is that I am unable to get my Speed Direct spreader bar installed, even with it turned together as small as it can be made. I could jack up the car and install it, but I would prefer fitting it, and then applying the preload. If I jack it up, and install it, I will have no idea how much preload is on it and it may actually be spreading, rather than supporting, which could affect alignment. So, I think this is a result of the .25 negative camber I had this time. It installed fine with my initial setting of zero camber, and then again with Bairs vendor at Positive camber i.e. both alignments having fewer shims.

jim2527

One of my side jobs duties is as an ECMO specialist (human circulatory and oxygenation support). We have 2 devices, the first has 2 basic outputs, flow and pressure. The second has over 10, flow, inflow, outflow, pre/post/internal membrane etc....

I'll get calls that go something this, "JIm, flows down can you come over to the unit??!!" I'll walk over, look at the outputs and explain that everything normal. A data point may be fluctuating 5.31, 5.33, 5.39, 5.30, 5.37 its real time data. I''ll tape over the last digit and the data points are now, 5.3, 5.3, 5.3, 5.3.... Similar to reading a dyno chart, 411, 415, 418, 412hp....eh, its all the same.

Same with alignments, get it as close as possible and don't worry about it. I slightly edited your numbers in the post quote. Look any better?

jb78L-82

I have not had my 78 professionally aligned since the Mid 80's..I kid you not..precisely for ignatz's reasoning. There is so much variation and fluctuation in the suspension of these cars that investing hundreds of dollars to get a precise numbers alignment is probably pointless unless you race your car on a track with said alignment is critical. The alignment specs also will immeidately begin to deviate once you hit your first bump and hole with a stock type suspension.

I have said this statement many times over the years that if you want your car to steer, handling and ride superbly over a stock type C3, you need to do anything and everything to eliminate unwanted frame and suspension movement:

Front:

Spreader bar
Poly Upper and lower control arm bushings (this is important)
Poly power steering ram bushing
GTR1999 custom blueprinted/rebuilt OEM steering box (important and critical for the car to track precisely) or Borgeson/rack and pinion steering
Modern 17/18 ultra high performance W/Y speed rated rubber

Rear
Monospring with poly cushions
Poly shock bushings
Competition Adjustable Heim jointed struts (VERY IMPORTANT)
Quality trailing arm bushings

Interior:

A sharkbar with heim jointed Struts in the interior to reinforce the birdcage to the floor seatbelt anchor point.

I have most of these modifications ^^^^ or some derivation of them and use the crude string alignment method and have for years. My car does not pull going down the road, steers straight and has never exhibited uneven tire wear...go figure?

All my modern cars get professional alignments...............

v2racing

You left out a very big modification that they need, weld the frame solid and gusset suspension mounts. My frame was full of bad welds and welds with cracks in them. I think most of them probably are.

Mike

The red arrows are cracks in the welds.


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lionelhutz

Try removing a 1/8" shim from the rear bolt and a 1/16" shim from the front bolt and swap them. That would be the same as moving a 1/16" shim from the rear bolt to the front bolt.

cagotzmann

Before you make any changes and move to DIY Alignment, make sure your DIY method works. Since you have a known alignment readings, start by just measuring the current setup with your preferred DIY Method.
Once you can repeat the measurements only then start making adjustments.

Also note moving 1 shim (front) effects caster / camber / toe settings. So you cannot fix caster without readjusting camber & toe. Also its normal to have caster out as much as .2 degrees side to side with a great alignment.
Here are the tools I use for DIY. Total time to take complete measurements is less than 10 minutes.



Camber / Caster


Toe Measurements.

jb78L-82

You should charge for your alignments....I bet it works really well AND 10 minutes to boot LOL

Torqued Off

Cagotzmann,

I understand your comment to measure my DIY method against the current and recent professional alignment. BUT, this professional alignment resulted in the car pulling to the right, repeatedly, and even in left lane with obvious left slope. So, something is not right. I was present during this alignment, right in the middle of watching him do the work and watching the screens as he worked on it. So, suggesting that I trust these alignment settings is my first disagreement. If the car would have driven without the right pulling that I experienced this weekend, then maybe I would believe I got a good alignment. But it was pulling right. I was not happy he was satisfied with the rear thrust setting, and after he spent an hour adjusting the left trailing arm shims, I believe he had enough, and suggest the right side was close enough. Not for me. BUT, based on what you told me, the car is NOT pushing left or right on hard acceleration, so maybe its okay. And nobody has suggested my right pulling tendency is a result of thrust issues on back end.

The pictures you attached show a bunch of equipment, and I understand how the caster / camber tool works, but your toe setup and pictures tells me nothing about how to do it your way. It appears you have a lazer sight and I suspect you are shooting it to these bars and measuring it. I have also seen your threads with an Excel spreadsheet to calculate it all........none of this tells me how to do it your way. And frankly seems overly complex, especially when the story is that its impossible to get numbers close. So, unless I get more information, and I mean details, I apologize, it does not really help. I will study the pictures and see if I can figure it out.

There are lots of tow bars sold, and other ways to measure toe, all of which seem blatantly simple, and I will just have to pick something. As for camber and caster, there are expensive tools,....and then there are blocks of wood and smart levels.

And all through this thread I started, many have posted about "accuracy" is fruitless, because the rubber bushings and general design of this car, accuracy is really "kind of close". So I am frustrated in the combination of statements of how accuracy is critical, but ultimately impossible, but I will find my way to do it.

I fully understand moving shims have other affects, but as others have pointed out, moving specific shim sizes equate to predictable degree changes. If I wanted to reduce camber on both sides, I remove 1/32 inch from each of the four locations, and it reduces camber by 1/6 degree. So, if I did that, my negative.28 camber numbers move to negative .11, which is closer to the ZERO camber you recommend. I can live with that. AND, if I want to increase camber on right side, to create the cross camber higher on right than left, I can remove 1/32 inch from front of right side, and add 1/32 inch to rear of right side. The poster suggests this 1/32 inch transfer equates to approximately half degree change in caster. So, if I accurately do both of these I end up with almost zero camber on all four, and higher caster on right side, within .21 degrees. I have no idea the effect on toe, which is the only thing I will have to determine. I will probably do it with toe plates and tape measures. All of this move the alignment numbers closer to your suggestions......and I will see how the car drives and how the tires wear.

All of my ideas are based on the recent alignment printout to be accurate....which again, I question. One note that really makes me question these "computerized" professional alignments, when Bairs vendor aligned the rear end, they had left final rear tow at 1/16. One month later, the alignment number I got for the same location was 0.00 toe, AND NO SHIMS HAD BEEN CHANGED. Which one am I to believe? So much for computerized accuracy. And the guy NEVER used the 1/32 inch shims I provided, and at same time stated he could not get anything closer because he used the smallest shims.....which was bullshit.

Torqued Off

Bottom line.....my car pulls to the right after spending $185 on a computerized alignment......what do I do now?

ignatz

Move the shim and see what happens - it ain't that hard

txfatboy1

Based on your pictures of the shim stacks, I would go to the drivers side and swap a single 1/16th shim from the front bolt with a single 1/8th shim from the rear bolt. You can do this with the car at rest, all 4 tires on the ground. Slightly loosen each shim stack nut until you can just get the shims out. Remove all shims from each bolt, making sure to keep the front stack separate from the rear stack. You will have to loosen the front bolt more to get the shims back in because you are adding 1/16th inch. This will lower the caster on the drivers side and SHOULD correct your pull to the right. Caster does not directly cause tire wear, but It will also very slightly change the camber and toe measurements. Make sure you tighten the shim stack nuts properly before driving the car. Your steering wheel may not be straight after the caster change. This is the easiest thing to "TRY". It takes about 15 minutes and should correct your pull. If it does not, most likely there is something else contributing to the the pull.... IMO, I would not have let the car leave my shop with higher caster on the left because of road crown... especially if there is enough adjustment to correct it.

Woody

Torqued Off

Thanks Woody, I may do just as you suggested. I do have 1/32 inch shims so I can approach it very slowly. If I assume the final alignment numbers the pro gave me are accurate, I can carefully document where it is now, and make small changes and see how the car drives. If it changes or gets worse, I can put it back to where I started. As for taking it back to this guy,....not happening. So I am going to have to figure a DIY method that works if I want to know what the numbers are.

lionelhutz

Try it and see what happens.

cagotzmann

To help Identify a possible cause you need to be able to take some measurements.

But I would rotate the tires to make sure its not the tires. ( if they are new with a few miles then this wouldn't matter)

I would measure using 2 conditions.
1. Direct on the pavement. ( don't bounce the suspension to settle ) then next step will show how much settle is in the suspension you have.
2. On some sort of skid pad. <--- when you take measurements on the skid pad and get a big change in readings, this usually means extra play in the suspension. While you get some play / change but it should be minimal.
I use this method after each track day to see when its time to repair items like ball joints / tie rods /bushings etc. While street driving you usually don't notice the change until they are badly worn. For the track I cannot have the alignment jumping all over the place.

This is what I use as a skid pad. These are simple kitchen cutting boards (plastic) with grease between the boards.

So the first measurement would be how even the rear wheels point to the front axle. With my laser setup as above pointing to the front axle, and measure the distance to the front axle like this.

They should be within 1-2 mm side to side. Then do the same measurements with the skid pads under the rear tires.
If one side adds more variance then there is more wear on the suspension on one side in the rear.
Also measure the camber change.

Then move to the front of the car. Center your steering wheel and reverse the measurements. Measure the left wheel vs the right wheel balance to the rear axle.
Repeat using the skid pads. Again left vs right should be in balance. ( this measurement it is possible to get a perfect reading since this is turning the adjustment tie rod sleeves the correct amount )
If they are not in balance then turn the steering wheel until the measurements side to side are the same and see how far off the steering wheel is. This might indicate one of the front wheels toe setting needs a better balance. Toe adjustment usually has a bigger effect when pulling to one side vs camber / caster ( if they are very close side to side).

But without doing any measurements and proceeding to trial and error adjustments then mark everything so you know the starting point. (tie rod sleeves) shim counts. You can always go back.

Just trying adjustments.
1. Remove 1 shim from the lefts side control arm (back position towards rear of car) reduce caster.

2. toe out the front left wheel. (since you had more toe in than required) try 1/4" turn. If this helps or now pulls to the left balance until you get the feel you like. ( this may off center the steering wheel, but you can correct by toeing out 1 wheel and toeing in the other wheel until the steering wheel is balanced again )

3. remove equal size shims left front ( both front and rear control arm positions) add positive camber )

If neither of these adjustments help then alignment may not be your only problem.

cagotzmann

This is the laser pointing to the measuring bar.

I measure the front distance vs the rear distance. eg total front measurement = 1875 mm ( I use metric since its much easier to using trig functions vs converting fractions to decimal) and to add simple measurement readings from above I would read as 907.5 or 908 its either 0.5 or 0 for me. This produces error of 0.01036 degree total toe error. you suspension settle is much higher than this.
Then mesure the rear distance.

In the picture I use equal length rulers to the front bar & rear bar are the same distance from the tire. Then I measure the distance between the bars eg (2764 mm)

eg front distance = 1875 mm
rear distance = 1880 mm ( total difference = 5 mm )
distance between the bars = 2764 mm

then the total toe angle = the tangent angle of 5/2764 = total toe = 0.1036 degrees

then use this https://robrobinette.com/ConvertToeDegreesToInches.htm
to convert to inches if you like. note the tire size effects this conversion.

Now for comparison using a sting method you would measure at the rim. Once you get a perfect box around the car ( very time consuming and impossible to repeat)
The best the human eye can read is ~ 1/32" ( is the measuring caliper touching the string or not )
on a 15" wheel ~ 16" measure distance @ 1/32" a single wheel you can measure tan (0.03125" / 16") tangent angle = 0.1119 degrees per wheel. that is 1.67 / 32nd per wheel. This is still acceptable but much more time consuming.

The larger the distance between the measuring points the more precise the measurement can be. So when I setup to measure toe it looks like this.


Just place the rulers under the tires and square the measuring bar to the rulers and the setup is 50 percent done.
Next pick one side and point the laster to the front and move the measuring bar to a exact number. ( doesn't matter what the number is let say is @ 100mm mark) then point the
laser to the rear bar, and again move the measuring bar to the "same number" 100mm mark. Now you are 75 percent done.
Next move the laser to the other side and take the readings.

eg pointing to the front = 1975mm
eg pointing to the rear = 1980mm
distance between bars = 2764mm
no calculator required difference = 5 mm then a little math you get the total toe.
then the total toe angle = the tangent angle of 5/2764 = total toe = 0.1036 degrees Once you do this often enough you realize that 5mm = 1/16" total toe
equal on both side = 0 total toe and a 5mm difference where the top measurement < rear measurement = 1/16" total toe out.

You can then make a simple chart calculating 1,2,3,4,5,6,7,8,9,10mm difference as a reference so no math is required when doing measurements.

This is very simple and not complicated less time consuming compared to using strings. The only thing you need to do when making actual adjustments for front toe is

center your steering wheel and set each wheel equal amounts from the rear axle. you don't care how much toe to set and only are concerned they are equal. Then adjust each sleeve equal until you get the total toe you want. After a test drive if the steering wheel is still not centered then you can again adjust each sleeve equal amounts ( one toe in vs one toe out to re center the wheel) once it drives nice you can again quickly re check the measurements.

My spreadsheet I use takes more variables such as laser error camber measurements tire size etc to make a perfect calculation but I have found the suspension moves enough that this simple method works very well. When I do my alignments for track days I set for 0 mm +- 2mm. Never use the spreadsheet again.