[200q20v] Re: DIY Alignment, was front suspension/replace tie rods

[Igor Kessel]

Bernie Benz wrote:

> Igor,  And I thought I was the only one!
> 
> After years of total dissapointment with the good, better, and best
> alignment shops and the LOM experts, I've been doing my own alignments for
> several years now.  But IMO, the problem is only half the alignment jockey's
> fault.  The other half is the unreasonably loose factory allowed tolerences,
> especially side to side tolerences, to which the jockies set (?) their
> go/no-go machines.

Same here, Bernie. For 7 years I designed sensors for Hunter, Bee and
several others. Yep, the ones that are situated in all 4 wheel
attachments and read the angle for the computer. The main reason why
Hunter eventually had chosen the reversed all-mechanical meter movements
over the electrolyte filled glass acceleration sensors was the very fact
that it proved to be impossible to get the alignment guys not to drop
the wheel units on the concrete floor every now and then. You can't
change the [negligent] human nature.

This is not to cast a shadow on Hunter - they are a great company and
make an excellent product hence they own ~80% of the market. Hell, they
even have their own airfield and several corp. jets. After having
spotted several test alignment machines in their plant, later during the
meeting I asked one of their engineers where did they take their own
cars for alignment. He: -"make a guess." :-)
 
> My tools are: framing square, 5' straight edge, plumb bob, tape measure,
> chalk, and a precision machinist's level.  

Similar. I use a digital gauge (first place after the decimal is good
enough resolution) that I've made out of a $100 Craftsman digital level
(half of it was generously contributed by Stefan for this jointly used
tool) and several Aluminium angle pieces. 

> For slip plates I have two pair
> of hard flooring tiles, greased, face to face.

Identical.
 
> As yet, I haven't come up with a good/easy way to check castor.  What's your
> trick?

Caster, we don't measure no stinky Caster :-).
Seriously, Caster is not adjustable in our cars and is essentially a
function of the body geometry. The last professional alignment that I've
done had shown Caster to be OK. Since I've never hit the car it should
remain to be OK. I do measure and compare the wheelbase side to side
every now and then. As long as it is the same and as long as the
steering wheel consistently returns to the straight ahead position I
don't worry about Caster too much.
Also, Caster is the only angle that does not contribute to tyre wear. It
may only make your car run in circles like the 0 deg Caster on the LH
side of my wife's Fox did many years ago. That poor car spent its first
5 years in NYC (where one service year counts for two like in the Soviet
polar submarine fleet :-) and was horrendously whacked in the front left
corner sometime in its life. It would run in circles if left alone until
no gas left but it did not eat any rubber.

Now, I have an idea of how to measure the Caster. I only need to come up
with some kind of a protractor like dial on the top piece of the greased
floor vinyl tile pair under each front wheel. Per Bentley the Caster can
be measured with my digital Camber gauge when the front wheels are
turned ╠20° side to side. 

-- 
Igor Kessel
'97 S6, PA plate "KBATTPO"
'98 A4, PA plate "KBATPO"