Date:         Sat, 16 Oct 1999 19:44:54 -0700
Reply-To:     "T.P. Stephens" <doktortim@ROCKISLAND.COM>
Sender:       Vanagon Mailing List <vanagon@gerry.vanagon.com>
From:         "T.P. Stephens" <doktortim@ROCKISLAND.COM>
Subject:      Re: DM Brakes
Content-Type: text/plain; charset="us-ascii"

>I guess I stand corrected! Maybe, or maybe not? I'm sorry if maybe I didn't
>word my opinion correctly and made it sound like rotors "always" need to be
>turned.

I doubt I was responding directly to any specific statement you may have made.
I am trying to reach people who have not yet learned the problems with being
penny smart and pound foolish.

If you have ever seen the rotors I've had to deal with I'm sure you
>would agree with me.

I've seen all kinds. The good the bad and the ugly. Fewer bad and ugly
and more good is what I strive for in my advise.


The DM may work well when people "take care" of their
>cars, and are compliant to the needs of said vehicle, but when you tell
>someone they need their brakes done and they show up two months later and ok
>the job..... !! By then the damage is done, nice grooves, gouges or whatever
>you might want to call them, in a nutshell its neglect. " I didn't have the
>money to do it then" .

I couldn't agree more. You must take care of your vehicle if you want it to
take care of your transportion needs.

Well I'm sorry but it will cost you MORE now, a price
>has to be paid! A little now or MORE later, took me 16 years to get this
>through my wifes head. (on her car of course!)  I like the idea of
>"scheduled maintainance" and I've always believed that the term "preventive
>maint." is a crock, you never prevent the inevitable from happening , you
>merely prolong it! i.e. I change my oil every 3k, does that mean my engine
>will live forever? not hardly , but it will live longer! It will eventually
>need bearings and rings etc.!

True indeed. In my mind, scheduled maintenance is per the factory charts.
Preventative maintenance is a schedule adjusted to account for the specific
type of use a particular vehicle undergoes and adding things not included
in the factory schedule, as an example, flushing and renewing the power
steering fluid to remove contamination and prevent the seals from leaking
till they are 20 years hard. Have you priced a rack lately??

The extremes of this example would be the garage baby that get's driven
a few times per year and a service vehicle that does 200 miles a day
in suburban rounds. Very very different needs and schedules. If your in
the meat of the bell curve between these two extremes your 3k statement
is basically true. If rather than using a generic rule of thumb you change
your oil by inspecting it's condition and color periodically and thereby never
let it get loaded to capacity with contaminants, you can then check your
odometer to verify the optimum interval for the way you use THAT CAR.

This is preventative as you can anticipate needs accurately and schedule
for the particular needs of this particular vehicle in a planned manner.
Under this scenerio you can extend that bering and ring job a most
amazingly long time. The rate of wear if the insides that never see dirty oil
is incredibly small, not just half the rate of most that push the interval
to almost black but more like 5% of that. Yes, I have seen 300,000 mile
bottom ends still within factory spec. The insides are still as clean
as the day it was assembled at the factory because the oil never got
overloaded to start depositing varnish all over the insides.

The key to either maintenance philosophy is accurate and detailed
documentation of service history. Amazingly valuable in designing
the most efficient future service schedule for any vehicle.

The other concern is the propensity of the factory marketing departments to
infect such schedules with compromises made to make the potential buyers
think that you only need the spark plugs changed every 100,000 miles.

I haven't yet seen a vehicle that can get more than 20,000 miles out of a
set of sparkplugs without gas mileage dropping several percentage points
on it's way up the excess resistance scale due to electrode errosion.
0.2 mm gap increase over stock is about where this problem begins. It is
the sharp edges of a younger plug with proper gap that keeps the spark
energy and combustion efficientcy high. It is also at around 20,000 miles
the spark plug threads can begin to bind and make removal of the treads
with the plug an increasing peril. Periodic removal is required for
thread maintenance with aluminum heads. Even if they have steel thread
inserts, let this go on too long and the insert comes out with the
plug being bound by hard carbon from slow steady and natural oil penetration
of the threads.

Thank you for the feedback, always appreciated.



Doktor Tim
Maintenance Repair and Restoration of European Vehicles
San Juan Island, WA