DIY alignment measurements

[beetlejc]

I've been having a hard time, nearing the end of my project build ('69 IRS Fastback) getting the alignment dialed in. (or, rather, Goodyear saying they could do it, telling me there's no toe adjustment in the rear or camber adjustment up front...BS...etc etc) But I didn't come here to rant about Goodyear.

I've paid for a multi-alignment deal for one year with them and they've already had it twice. I've been taking the car back and resetting the ride height closer and closer to stock, still with a slight forward rake. After literally studying the alignment printouts (before & after), I'm back to lowering the rear end (saggy butt look IMHO) but I'm guessing that'll help some of the caster issues up front, allow more toe adjustment in the rear etc etc. I've also been eyeballing my own DIY alignment with string and tape measures to get it close and drive-able for testing. I'll take it back to them for the actual (hopefully, final) computer analysis.

I've found that the generally-accepted rear toe-in measurement for the rear is about 1/8" (based on a centerline "string" method) but I don't have other such numbers for front toe or camber. Unless someone can introduce me to a cheap (free) method of finding the degrees listed in the Bentley, I can really only use actual measurements. (like the "1/8 inch toe-in" for the rear) Can a plumb be dropped from the top of the front wheel to provide a rough measurement from the bottom edge to give me an approximate positive camber measurement?

Any counsel here would be great.

[KTPhil]

You want 0 to 1/8" toe-OUT at the rear. (EDIT see below, this is for swing axle only, not IRS)
You want 1/8" toe IN at the front (both swing and IRS).

[eashc]

Heres what this guy did. Not sure how much room you may have

https://www.thesamba.com/vw/forum/viewtopic.php?t=670939

[beetlejc]

[beetlejc]

[KTPhil]

[raygreenwood]

[KTPhil]

I've aligned my swing axle bugs this way, and the improvement from getting rid of rear toe-in was quite noticeable. For the swing axle Type 3 the Bentley specifies -5' ±10' (slight toe out).

Does the OP have swing or IRS?
(EDIT: I see he said IRS, so yes, the IRS likes zero to a slight toe-in at the rear).

[raygreenwood]

[Donnie strickland]

As an example, on the 1966 cars the rear track is wider than the front:

And the same on a 1969 car:

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71 Elm Green FI A/T Squareback

[raygreenwood]

Exactly what I was about to get into. If the rear track is wider I can visualize thst some rear negative camber may help.

Digging through the books a little yesterday.....virtually all of those with positive rear camber listings have rear tracks narrower than the front.
Ray

[beetlejc]

Thanks for the continued discussion, guys.

So I spent the remainder of the weekend (and not reading the forums):
-dropping the rear one inner spline & setting the rear to 1/16" toe-out

I don't like the looks of it. I had the whole vehicle sitting at stock ride height...slightly higher in the rear, and it looked "correct & appropriate" but I was out of toe-in adjustment at the right rear. Now it's probably closer to actual factory (rear) ride height but has the saggy butt look. Couple that with the fact that I should be aiming for some rear toe-in and I'll be back to work on it this weekend:

-raise the rear one outer spline
-set the rear to 0 - 1/8" toe-in if possible (maybe by changing it up by only one outer spline, it'll leave enough room to find one more mm of toe adjustment)

The upside of all this is that I'm getting fast enough where I can reset the ride height/adjust spring plates in an evening after dinner.

[KTPhil]

You probably know this, but to be clear, rear toe is adjusted by sliding along the spring plate, so it should be almost independent of camber and ride height at rest.

[beetlejc]

[beetlejc]

Well, I've been progressing on this gradually. It's been difficult to wrap the T3 project up and maintain a westy at the same time.

I've set the rears as far forward in the slotted spring plates as possible and the RR measures 0 deg...maybe 1/16 toe-in if I squint. I had to grind the slots slightly larger. Since this used to be an automatic, (i.e. not the original tranny) I'm tempted to think that maybe I could/should find a way to move the whole engine/tranny assembly rearward slightly by tweaking the mounts somehow. (thereby causing the axles to go forward some...toe in.)

Thoughts on this?

Now I'm working on the front alignment. By drawing a line through the center rib of the tranny and case halves all the way past the front beam, (This is how I measured toe in the rear) I hope to set the toe (in) up front. My initial measurement shows about a 3/4" difference in toe-in from RF to LF. Believe it or not, I actually dropped a plumb from the tranny rib and the case seam and pulled a string all the way up front. If I eyeball it, it looks surprising spot on.

1) Does this method sound...sound?
2) Should each wheel assembly measure equally (toe-in) to the centerline? (you'd think so)

Incidentally, I measured the ride height and set blocks under the center section of the rotors so I could remove the front wheels and get at the steering bits while still simulating "weight-on-wheels."

I'm irritated with the camber adjustment. Basically, I have the RF set at 91.4 deg (essentially, 1.4 degrees -in-spec) and the LF is set at 90.7 deg. -a difference of .7 degrees with no more adjustment. I'm using an iPhone angle finder app...slick but...

Thoughts?

[raygreenwood]

[beetlejc]

Thanks for the input, Ray.

1) Thanks for clearing my head on bit on thoughts of nudging the engine/tranny rearward. IRS...CV joints....duh. You are correct.

2) My thoughts on the "centerline" method stem primarily from the old "Thrust" alignment days. i.e. set the fronts based on the alignment of the rear. I'll go ahead and measure the beam for a centerpoint as well.

3)It is somewhat dangerous. I initially had jackstands under the center mass of the rotors but that was just slightly too high. I have, however, positioned my tires under the front beam. (old "just in case" habit) Point noted about the potentially incorrect measurements. Thank you.

4) As far as the phone angle finder, it's being placed, without cover at a few places around the face of the rotor. (above and to the side of the grease seal for a reasonable "sanity" check.) I definitely had to wirebrush off some residue before starting.

Overall, you've given me some food for thought. I'll be able to spend some more time over the weekend puttering around this task.

[raygreenwood]

The thruat issue.....I have been thinking about.....and have no "DYI" advice to give yet. Others may have.

Its the most difficult issue with trying to do alignment yourself. With the age of our vehicles and the number of potential accidents, repairs, age etc.........its common that the rear and front suspension are no longer exactly on the same centerline.....which is why I would not use the rear suspenaion to find the centerline of the front.

When setting the "thrust"......which is very important.......the front suspension is set centered to the chassis......based in steering wheel being centered.....and hopefully the chassis nit being bent.
Then the rear wheels are set to track with the front. In reality the chassis could be crooked to the cejterline thrust....but at least the rear wheel toe angles will be set to follow the front and not steer the car.

I have actually seen a few poorly cobbled together cars over the years that have such twisted chassis.....that they look like they have a 10° angle on them in ine direction...yet.....thruat was able to be set and they steer straight at least.

This is why it is probahly best to set your front toe in and camber.....and then take a few measurements to make sure that the rim at its narrow and widest spots of toe-in are the same distance from both fender and inned tub firewall.....and steering wheel is straight.

Then do the rear suspension. I met a crazy guy once who used two pair of steel bars moujted to the wheels spanning 6 and 12.....and on the front wheela he used little steel rulers mounted to the steel bars.....and on the rear......he mounted an $800 rifle scope he had to set the rear wheel thrust in the same direction as the front... ......and the car steered great.
At the time I though he was an idiot......but looking back.......not so much now. Ray

[beetlejc]

I decided to go ahead and take the plunge and replace the diagonal arm bushings. I'm hoping this will correct my inability to dial in the proper alignment.
I found that a couple of old main bearings were the perfect size help press these in with my vice.

First one is done. I'm also giving them a coat of POR15 that I had left from a sample pack I bought a couple years ago. The coating is great! -a nice hard "shell" and good and black.

Has anyone else ever noticed that some jobs just seem to use every single tool in the house? This is one of those.

[Roadbeater]

Interesting on your front alignment issues, I just went through my suspension this winter, and am trying to get it aligned. Lh front is .6 degrees in, the rh front, I can only get to maybe .2 degrees inboard. I see some people are recommending 1-2 degrees in for camber, not sure how they are getting there, as the rh side is all I can get.

On the rear, I was able to get the toe in set pretty close, but replacing the 47 year old bushings had to help, no idea what it was before. Will be interesting to see how well it drives now.
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69 Fastback