I'm kinda surprised that you were able to align the car with the upper A-arm reversed, but there you have it. And, as you well put it.... Sigh...

As there are many "string methods" for doing a rough toe-in, I don't know which one you mean specifically, but here's what I did: Load the car with a spouse or kid or the like, and bounce the car around a few times in the front to get the shocks to "settle". I then ran a string past the 2 tires on one side of the car from the rear of the car all the way past the front, securing the rear part of the string on a jackstand a foot or two behind the car. Then pull on the front of the string (a few feet in front of the car) and secure it again to a jackstand or the like. Now, the tricky part. Adjust the front and rear jackstands so that the string touches just barely on both sides of the rear tire, halfway up the tire. Then, see where it touches on the front (again, it should be halfway up the tire). Since the front tire has a very slight toe in, when it's adjusted right, the string should be touching on the rear of the front tire just slightly more than the front. I'm not sure how accurate this all is, but it seemed to work well enough for me, at least as a starting point rough alignment.

Let us know what you find out.

-Bryan

Bryan,
My method will be very similar except for one critical issue. The width of the track at the rear is 30mm less than the width of the track at the front. So using your method will not have your string parallel the centerline of the car. So my plan is to set a line offset from the centre of the wheels at the height of the wheel centres and compensating for the track width difference. Then i will measure from that reference line to the rim of the front wheel and adjust the tie rods to set the toe-in. More details to follow.

cheers
dinghyguy

That's a good point about the different front and rear track widths, and one that I had not considered. Perhaps a modification of my method would be to set up parallel rear to front stings on both sides of the car simultaneously, and then measure the string to string width at the rear of the car (near the wheels) and then at the front of the car (near the wheels) and see how far off the two strings are from being parallel to each other. Then, you could move the rear of the strings just slightly away from the rear wheels, and remeasure until the two strings are exactly parallel front to rear. Then measure the toe in at the front wheels by the difference between the string and front and back points on the rim or tire.

Or, just take it into an alignment shop and pay $59.95 or whatever and have it done! In the past, I've watched these guys align my cars, and I kept thinking, man, can they really get it aligned properly in 30 minutes including set up? That's when I started playing with ways to do my own alignment, at least for toe-in. After I did this "self-alignment", the car did seem to track and steer better. And the steering wheel spokes were level when going straight.

-Bryan

Well the toe-in alignment is all done and it was virtually painless, see writeup below.




That about does it for mechanical and electrical work in the near future (i hope). A few items in the interior still to be done and then the dreaded bodywork on the rear fenders. But that will wait until my new garage is built! In the meantime ther eis the other '79 fiat to play with. Oh and of course driving them both!

cheers,
Dinghyguy with rain pelting down on my popup garage!

To keep the steering wheel level/centered a rolled up blanket or foam pad wedged tightly between the drivers seat and the rim of the steering wheel works quite well.

Nice work, Dinghyguy! But, you of course realize that I am eagerly awaiting your treatise on how to set the caster and camber at home, with just basic tools....!

-Bryan

Yeah! I wanna see that done!

Wow, a challenge...….

Well after a good 8 minutes of research i found out a couple of things. For about 20$ i can buy a magnetic caster camber level gismo that attached to the wheel (if steel). Basically it is to measure the angle of the wheel from vertical. But can i do it with what i have?

So thinking about that for a bit suggests a level or plumb bob hanging from a dial gauge mag base and the digital caliper should work for camber as long as the vertical reference can stay vertical but the ground must be level across the two wheels. Imagine you are going all this on a side slope and referencing a plumb bob, the angles for camber would be dramatically different for each side of the car.

Castor is a bit more challenging, because it needs to be measured with the wheels turned 20 degrees and you are supposed to have fancy turntables under the wheels for both friction and ease of the 20 degree angle measurements. Well being cheap i figure if i borrow the plastic cutting boards from the kitchen and use a straightedge and some geometry i can make the wheels turn 20 degrees in a repeatable way.

So, in summary, a flat floor, 4 cutting boards, a mag base to hand the plumb bob, digital caliper, plumb bob, level, protractor or square and tape measure, calculator with sin, tan etc and the rest is geometry.
Oh and i have to take off the alloy wheels and put back steel wheels for the mag base.

Problem solved......theoretically at least. In practice because shims may be needed and stuff has to be lo0sened and tightened and remeasured etc. this could well be a tedious task, particularly if you don't have shims readily available.

I look forward to hearing how it works for you Todd or Bryan.....

cheers
Dinghyguy

I'm intrigued by your ideas, Dinghyguy! Quite frankly, I have watched how shops have done the alignment on my Fiats in the past, and I kept thinking, "Man, I could do a more precise job than these guys and save myself $79.95."

On my '71 spider, the good news is that I finally finished the electrical work and brakes and front suspension, and so I fired it up and took a spin around the block. Needs some tuning and such, and of course an alignment, but it ran surprisingly well after having been in storage the last 5 years. The bad news (and it's not really bad news) is that I still am probably a month or two from getting to the point of needing to do the alignment. Still need to finish putting the interior back together, and some minor stuff like the wipers halting midway rather than in the fully "down" position (see my other post under electrical).

But, I'm eager to turn your theory into practice, so let's see who gets there first. Perhaps we could even start a new thread on this, like "DIY front end alignment".

-Bryan

Of course you would come up with the answer easily! Nice, dude!
I actually accomplished a rough toe-in on my car by eye. And I'll have the thing fully aligned, since it will probably only happen once more in the car's lifetime,...and all of the front suspension is new.
I do love puzzles, but I have too many machines to maintain, and I'm too old to spend too much time at just one, so I'll farm this kind of project out to someone else,...
Cool that you can do your's!
Have fun driving those Fiats! Todd.

The local Firestone store has a very good alignment guy and $100 got me a Lifetime Alignment. While they may balk about doing it laden they do it and with the type of suspension on the 124 an alignment is something your going to be doing every year or so if you put any real miles on it. Last free alignment showed that the center link from IAP that the previous owner put in about 20,000 miles ago has worn out and needs replacing. The ball end of the center link at the idler arm is what has failed.

Be mindful that according to Eli's "Quick and Dirty Suspension Primer" on MiraFiori the fastener torques on the front suspension need to be checked and brought back to spec at every oil change. Failing to do this can lead to more frequent alignments plus component and frame failures.

By the way, I wasn't suggesting that there aren't any shops that do high quality alignments. My experience has just been hit or miss, but if you find a shop that knows what they are doing, stick with them. With laser alignment systems, you can get an exact alignment if the guy knows what he is doing and is using the right specs for your vehicle.

I'm just somewhat suspicious as the last alignment I had done on my '69 left the car with hard steering. Since I had also gotten new tires, I figured that's what it was. Since the car is only driven a few hundred miles a year and the issue was only when making tight turns at low speed, I kinda ignored it. Until one day when I said, what the heck, I'm just going to check it myself. So I did a modified version of what Dinghyguy suggested above, and sure enough, the toe-in was pretty far off although not really visible when just looking at the front wheels. My guess is that the shop used the specs for a different Fiat model, or missed a minus sign somewhere or the like. I got the toe-in back to roughly where it should be, and the steering is now much lighter.

-Bryan

For Dinghyguy: Something to add to your excellent writeup: Make sure the tire pressures are set to spec before starting.

If you ask 10 people what tire pressure they suggest for Fiats you'll likely get 11 different answers, but still, it's best to do an alignment with the pressures pretty close to the manufacturers specs. Of course, if you're using different sized tires than original (very likely), it can get complicated, but at least make sure all 4 tires are the same. And do the alignment at the pressure that you tend to keep the tires at, whether 23, 26, 28 psi, etc.

-Bryan

The steering geometry on the Spider is pretty wild by the nature of being double control arms with a trailing center link so if you align the car unladen using the laden specs the front wheels will toe out once you sit in it and after a while you will get pretty bad inside tire wear.

You will notice that the front wheels will be extremely toed in when you jack both front wheels off the ground which is the nature of how this suspension system works. Another thing you may notice when the alignment is not done laden is that when you go over a hump in the road that since the front wheels are already toed out too far due to the poor alignment that when the front suspension compresses you can get a pretty loud chirp from the front tires as they toe out even further.

Driving down the road as you transition over the road and all its irregularities the front wheels are going to be in a constant flux of toe in and toe out so the laden alignment is very critical to have that initial position set correctly to minimize tire wear, steering effort and tire squealing/chirping.

Thanks, both excellent points that i will add to my document.
Note that the specs do say "laden" but emphasis is a good idea.

cheers
dinghyguy