Lowering by adjusting spring plates - any experience?

[Dirk Heinrich]

1.4 or 2.3 degree correction is not possible as the smallest increment is 50 arc minutes.

Thx for the comments Albert - I am not sure if I fully understand though.
Also this is what I meant:
1 degree has 60min - therefore 2 increments make 1 degree and 40 minutes (which I meant by "1.4") and 3 increments make 2 degree 30 minutes (2.3).

I do need to correct the toe-in. Intuitively I'd say it is too much now. Can I do the alignment myself? I hope so

[Albert Tiedemann]

All:

Here is a bit more explanation of "not possible".

There are 40 inner and 44 outer splines or 9 degrees of arc movement [360/40]/inner spline and 8 degrees 10 minutes [360/44]/outer spline of arc movement. Math 0 could not be easier unless you forgot that a circle has 360 degrees.

Thus the difference, one forwand one back is 50 minutes of arc, or more generally m splines forward, n splines backward = x times 50 arc minutes where X is the difference between m and n. And visa versa.

1.4 degrees is 84 arc minutes and not divisible by 50 with no remainder [so not possible]
2.3 degrees is 138 arc minutes and not divisible by 50 with no remainder [ditto]

However, the tolerances allowed by the Factory are greater than the 16 minute or 12 minute inherent error[you cannot work any closer than 50 minutes] even though you know or want 1.4 or 2.3 degrees. The only way this is possible is to install an adjustable spring plate. With this installed, you can adjust the value to any increment you want. You can even do it on the alignment machine and watch the result interactively. SwayaWay[sp?] makes these for VW. You need to add a feature to the purchased part for the washer mentioned below. They are priced about $200

I suppose you could set the rear toe yourself, but you need a way to measure the result.
Strings and things might work for some, but the alignment machine is the hot lick. It is easy. The position of the axle is set by the nose of the rear bearing housing cover in contact with the thick washer attached by a through bolt on the spring plate. This is the bolt you NEVER loosen when doing any work at the spring plate because it sets the toe in of the rear wheel. Since you have one on each side, the toe can be set differently side to side although I do not know why you would do it. If you want to change the toe with the car on an alignment rack, you need to loosen the three fasteners securing the rear bearing housing to allow it to be forcibly displaced. The washer should be clear of the nose before movement. After you get the toe where you want, just install the washer against the nose of the rear bearing housing and tighten the through bolt that is only loosened for this work procedure. Once set, you are good to go for this particulate camber setting. Be sure to retighten the three bolts that you loosened to set the desired value.

Hope this helps.

[Guest]

Because of the differential of splines you can do steps of
about 3/4 degree. Make sure you give the trailing arm a
slight push upward to take the play out and if the car is
not level front to rear be sure take that into account of
the arm angle. It is not necessary to have the car level but
you need to take that into consideration in the arm angle.
For example if the car is nose down by 3 degrees then you
want to set the arm 3 degrees less than required. To make
the car level is the best way for a first timer. To fine
tune the level just support the front by a jack and then
just adjust it till you are at true level. You want to
measure at the body edge that is just inside of the door at
the sill, it is all metal.

Alan

ladirk@gmx.net wrote:

Thx Alan, This really helps!

The inner has 40 notches - 9 Degrees change, and the outer has 44 notches - 8.1 Degree change. Hence, 4 inner down and 4 inner up should result in 3.1 degree (1 degree equals 60min). Or, 5 inner down and 5 outer up should give me 4 degrees, which might be what I am looking for (about 1 1/4 lower). I'll publish my results in the forum.

Dirk

-------- Original-Nachricht --------

Datum: Thu, 11 Sep 2008 21:11:30 -0700
Von: Alan <stable356@earthlink.net>
An: Dirk Heinrich <ladirk@gmx.net>, 356Talk <356talk@356registry.com>
Betreff: Re: [356Talk] Lowering by adjusting spring plates - any experience?

Dirk,
I have a table I developed to set the rear height at the
wheel center. One inch of height change is about 3.3 degrees
of swing arm change. If you just move it one tooth you will
be changing the angle by about 10 degrees which would mean a
change of 3 inches. To do smaller amounts of change you need
to change the inner teeth also. The torsion bar has
different number of teeth on each end. To change smaller
amounts you need to play the inner to outer teeth against
each other. This is the "vernier" effect. If you turn the
bar one inner tooth in one direction and then go the other
way on the outer teeth you will change the angle less that
on degree, about 3/4 of a degree. Remember to push up
slightly on the arm to remove any play in the system and you
want to try to have the left side 1/2 higher to compensate
for driver weight.

Alan

PS Good time to replace the bushings.

Dirk Heinrich wrote:

1 1/2" would actually do it. Does anyone know, how many notches on inner
or outer splines of the torsion bar that would be? I do realize that I
might have to combine some inner turns with outer turns to achieve that
- is there a list for the various lowering combinations.

Thx again,
Dirk


------------------------------------------------------------------------

Dirk

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[Dirk Heinrich]

Again I feel lucky:

Today, I did the leveling and it only took me 1 1/2h to adjust the radius arm on the driver's side - actually most of the time went into putting the axle tube back in place on the radius arm.

Again, after taking the tube of the radius arm, I measured the distance from the bottom of the inner hole (close to the never-to-be-taken-out-screw-with-washer) to the ground. Then I "vibrated" the radius arm off (that is a good technique if the torsion bar tends to come out - again the 356A set-up does not allow to hold the torsion bar in while pulling the arm of), grabbed the torsion and turned it one notch down. While holding the ruler up, measuring the distance from floor to the hole again, I eased the radius arm back onto the torsion bar. And bingo 7/16 difference - exactly what I wanted.


I believe I moved the radius arm 50 min south (9 degrees on the inner spline and 8 degrees 10 min back on the outer spline). But again, it doesn't really matter as long as the car sits well.