[T3] Nose too high.

[Jim Adney]

On 14 Jun 2019 at 22:34, Keith Park wrote:

> All old cars, torsion bars or leaf springs or coil springs seem to sag with
> age, leading to spring replacement or coil overs, im not a physicist so I
> cant comment on the physical nature of the spring steel
> but it does seem that they sag out with age.

Springs can appear to sag if they develop tiny cracks that reduce the active 
area of the spring. This happens, but in leaf springs, one leaf can fail leaving 
the car lower but the other leaves holding the weight. With torsion bars, 
there's no sharing, so a crack tends to propagate and fail soon. I had one 
torsion bar fail, and that had a distinctive creak as it flexed. That eventually 
broke, but it took a couple years to do so.

We had a rear coil spring break on our Jetta wagon a couple years ago. 
That went without any sagging that we noticed. 

> Mine was measured on the 71, and it may be that the front fenders may vary a
> bit on lip height, also some of the rubber snubbers, especially the lower
> were a different shape than others but my main concern is that there is
> adequate suspension travel so your not bottomed out all the time if the car
> is loaded down with cargo or people and not so high that your hitting the
> top snubbers every time you go over a bump and it springs back.  The lower
> the front end sits under these conditions the better, within reason.

I agree with all this, except for the last sentence. I suspect that stock height 
puts us in the middle of the range of travel between the rubber bumpers. Any 
deviation from this reduces our travel in one direction or the other. I'm not 
sure of where my '73 stands, because my lower bumper is gone on that car. 
I'll have to check the other side. (I should check the other side for height, 
too, just to add another data point.)

> small changes in the distance between snubbers and arms also result in more
> significant changes in body height, so its likely that a range of over an
> inch or 2 would still have the suspension sitting in an acceptable range of
> motion and caster angle.

You're right, the bump stops are maybe halfway out on the trailing arms. I 
should measure those distances. 

> on the 71 right now, if I put my fingers on the top of the tire, I can raise
> my hand about an inch before the backside hits the lip, on the rear my
> fingers and back of hand are both contacting the tire and lip at the same
> time.  I can put the rear height wherever I want with the air shocks, but in
> its current state the rocker is about a half inch lower at the front than
> the rear, 10" at the rear, 9 1/2 at the front.

Where are you measuring the rockers? (bottom of the lip? flat outside the 
lip?) I can try to compare.

I wonder what happens if you let down the rear air shocks. Does the front 
come down equally or might that even things out? The extra weight of the 
Type 4 engine back there makes this harder to predict.

>From the hand test, I'd say that you're high on the front but about right on the 
rear. I've been doing the hand test for decades, and it hasn't changed much. 
I don't know why the rocker numbers don't support this, but maybe it's all in 
the front fender shape.

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Jim Adney, jadney at vwtype3.org
Madison, Wisconsin, USA
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