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

[Bernie Benz]

Castor:  Likewise, I've considered it of little import, but just as a matter
of principle, it would be nice to know where it is up front.  I've adjusted
it (everything is adjustable, if the desire is strong enough) only after
knowing with certianty that toe and camber are identical on both sides, and
where I want them nominally.  Only then, if the car does not track dead on
do I play with castor on one side.

Have you ever done a bump steer evaluation on your Audis?  I've not yet done
so on an Audi, but I have a Mcpherson strut Lancia Scorpion that was so bad
that I had to lower the forged steering arms intergal with the wheel bearing
housing by 3/4 inch to center the neutral steer in the suspension travel.
(Heavy duty torch work.)  So, I suspect that, if not a stock suspension
problem, the lowering fad has moved the ride height into areas of increased
bump steer, and resulted in much of the ploughing and understeer complaints
expounded on our Audi lists.

-- 
Bernie

'87 5KTQ     260K
'90 90Q-20V  130K
'91 200Q-20V 130K
 
> From: Igor Kessel <ikessel at amexol.net>
> Date: Thu, 31 May 2001 22:38:10 -0400
> To: Bernie Benz <b.m.benz at prodigy.net>
> Cc: 200q20V mailing list <200q20v at audifans.com>, audi-20v
> <audi20v at rennlist.org>
> Subject: [200q20v] Re: DIY Alignment, was  front suspension/replace tie rods
> 
> 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"
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