That is information, correct or incorrect, that was passed along on a
Ray and Bob show.  These guys do Car Talk.  They have a website.  They
are graduates of MIT, and I a.s/u/me that because of their higher
level of education, they know what they are talking about.  Many other
people make this same assumption.  They also run a car shop, and speak
from their own experiences.  In fact their *job* is to give car
experience to other people.

Since they broadcast on radio, and have an open website, challenges to
their ideas would appear from everywhere.  I've never seen anyone
challenge them on the analog vs. digital pressure gauge issue.

Lg

That is information, correct or incorrect, that was passed along on a
Ray and Bob show.  These guys do Car Talk.  They have a website.  They
are graduates of MIT, and I a.s/u/me that because of their higher
level of education, they know what they are talking about.  Many other
people make this same assumption.  They also run a car shop, and speak
from their own experiences.  In fact their *job* is to give car
experience to other people.

Since they broadcast on radio, and have an open website, challenges to
their ideas would appear from everywhere.  I've never seen anyone
challenge them on the analog vs. digital pressure gauge issue.

here they say *some* digital gauges are "surprisingly accurate"
==================================================================
Dear Tom and Ray:

I have three different tire gauges, all of which give me different
readings. They are all the old-style "pencil type" gauges, and all are
made in China, if that makes a difference. How do I find one that can
be trusted? -- Jerry

RAY: Well, the pencil-type tire gauges, with the pop-up plastic
readouts, are notoriously inaccurate. You could buy five more of them,
and you'd probably get eight different readings.

TOM: And the dial-up gauges used on air pumps at gas stations are even
worse. You set it for 32 psi, you hear "ding-ding, ding-ding,
ding-ding," and you drive away with 80 pounds of air in your tires,
with your head bouncing off the ceiling.

RAY: We use a very precise dial gauge at the garage that cost us about
100 bucks, and it's a beautiful instrument. We keep it under lock and
key, because if we didn't, my brother would use it as a hammer to free
up stuck brake calipers, or to crack chestnuts.

TOM: But I'll tell you what. We got some samples of some inexpensive,
battery-powered plastic gauges with digital readouts. Surprisingly,
they were extremely accurate. You can get them at almost any
auto-parts store now. They cost 15 or 20 bucks, and they use
replaceable batteries.

RAY: Yeah. The batteries cost 14 bucks.

TOM: Nah, they're watch batteries; 3 or 4 bucks a pop. In any case,
whoever makes these gauges (and I'm sure at least some of them are
made in China), this style seems to be far more accurate than
pencil-style gauges. So, that's what we'd recommend for you, Jerry.

http://www.cartalk.com/content/columns/Archive/2005/June/07.html

===================================================================

You'll note the STANDARD they keep "locked up" as a reference is a
dial type.

Humans being contrary critters, here is what Tom and Ray have to say
about dial gauges:
===================================================================

Dear Tom and Ray:

My question is in regard to proper tire pressure. When you buy a new
car, the owner's manual tells you to abide by the sticker inside the
door post. My present car calls for 30 psi in all four tires. But when
I get the car back from the dealer, the tires generally have 36-38
psi. Do they know something I don't? -- Howard

Ray: No, you apparently know something they don't, Howard. Either
their equipment is inaccurate, or they're just being careless.

Tom: Or perhaps, after the Firestone tread-separation debacle, they're
so afraid of underinflating tires that they're being overzealous and
overinflating them.

Ray: But you're absolutely right, Howard. If you have the original
tires on your car, or approved replacements that are the same size,
then the pressure recommendation in the owner's manual (or on the door
post) is the one to follow.

Tom: Just be sure YOUR measurements are accurate. You have to use a
good-quality tire gauge.

We recommend the round gauges with the needle, rather than the
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
"pencil" type gauges with the pop-up indicator.
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
Ray: And be sure you're measuring the pressure when the tires are
relatively cool, since heat from driving can dramatically increase the
pressure. So if you take a 30-minute drive home from the dealer --
including a jaunt on the highway -- and then hop out of the car and
measure the pressure, it's likely to be inflated by the heat generated
during the drive, and it will give you an inaccurate reading.

Tom: But if you're checking the pressure with a good gauge when the
tires are cool, you have every right to ask the guys at the dealership
(nicely) to shape up and be a little more careful from now on.

http://www.cartalk.com/content/columns/Archive/2001/April/05.html

======================================================================

So here, they contradict themselves and "recommend the round gauges
with the needle."

So which is it?
On their advice, I threw away what I thought was a perfectly GOOD
digital pressure gauge, and went out and bought an analog dial gauge.
Now they turn around and say digital.

Lg

I know what you are saying, but you dont get away from some
irritating jitter or shimmy, whether it pulsates through the pedal
or not.

Maybe you hear it, maybe you sense the jitter or shimmy, and
as I agreed, perhaps you dont feel it in the brake pedal (as pulsation).

There will be mechanical vibration due to the inertial mass of the caliper
being slapped around by a  disc which now has the profile of a camshaft.

The beginnings of irritation.....

The pedal pulsation effect, as earlier agreed, is caused by thickness
variations
in the disc.

To fix the problem, sometimes you have to do more than just turn the rotors.

Are we still in disagreement>?

Fortunately, servicing brakes isn't rocket science.  Even I can do it.
The problem for a lot of people is, out of sight, out of mind.  You
wouldn't believe how bad a lot of rotors look out there in carland.
Of course the newer models aren't old enough to show neglected brake
service, but older cars, most of them, look like death on wheels.

I have all the tools now to do the job right.  I last checked them
this past summer and they looked OK.  But now I have the measuring
stuff to go in there and really log some numbers.

I would rather _not_ leave this to some shop.  The last time I took my
car to Auto Clinic, they reamed my wallet, and reamed my vehicle.
They did a butcher job on the rotors.  I should have filed a complaint
with the Better Business Bureau.  But now that I know how to do this
myself, it will be done correctly from now on.

I still have to flush my lines, and do have the equipment for that
also.  When I finish learning how to STOP A VEHICLE RELIABLY, then I
will spend more time on learning how to make it GO reliably.  This is
a combination of study, and experience, and having the right tools.

Lg