I found out from another thread that brake rotors can't warp and it seems
nobody on this planet can really (reliably) tell the difference between
brake friction materials (because there are no standards whatsoever)
according to
http://www.performanceoiltechnology.com/brakingsystems.htm
So, since I have horrible brake-induced wobble in my Toyota 4Runner, how
DOES anyone buy the right parts given there are no regulations or
standards to protect us?
We may as well close our eyes and choose randomly for all the lack of
standards. Which leaves me to my most important question, having to trust
in your judgement and experience (which I don't have).
Where would YOU buy a good quality rotors & pads for a Toyota 4Runner?
Stu
Wrong - been certified as a brake expert in Federal and State courts, having
designed and built many kinds of brakes as well as brake testing machines
for Detroit and Japan, and have done hobby work on race cars for 35 years -
rotors warp out of plane.
And I have pulled off a fair number of rotor plates that were definitely
warped.
From your cite:
"The problem with this diagnosis and repair procedure is that first of all
is that brake rotors do not warp. "
Wrong. They do, especially the ones that have offset bells. How can that be
if the website says it can't?
Again, from your cite, as they state one sentence beyond where they say it
does not exist.:
"Brake rotor disc thickness variation or excessive lateral runout, as well
as drums that are out of round can cause vibrations and pulsations in the
brake pedal and/or steering wheel. Brake lining material transfer onto the
rotor can also have an effect on this as well."
Check out what they said about the rotor in their excerpts above- "it's not
warped, it really just has its faces warped out of plane" yes, BS
doubletalk is what you saw on that site.
" It's not a duck, its really a mallard or its a bird with a green head
that has webbed feet and quacks":
1) "Brake rotor disc thickness variation" means the planes of the rotor face
are no longer flat with reference to each other, and if beyond allowable
limits, each the face of the rotor has warped out of the permitted plane
with respect to each other. That is called warp. (of the rotor face plane,
the part the shoes contact).
2) "Excessive lateral runout" means the plane of the rotor face is no longer
in the range of allowed plane, when measured by a runout gauge mounted
externally to the rotor, and thus the face of the rotor has warped out of
permitted plane.
(to make a runout measurement - mount rotor in trued solid axle, set
preloaded gauge on face, and turn rotor one turn while checking gauge to get
max and min: subtract to get total runout)
"Excessive lateral runout" can be due to excessive "brake rotor disc
thickness variation" or bent mounts or twisted rotor.
Rotors are made thin so they can be light and keep fleet/vehicle mpg down.
Even a first year engineering student can tell you how hard braking with
the linkage turned hard over bends (warps) the rotor bell.
(imagine 2 tons moving forward trying to go over a tire turned sideways
with the brake pads locked onto the rotor, a rotor designed for transfer of
force into floating claipers and transversely into the axle.
Guess how the force gets from the 2 ton moving vehicle mass into the tire
tread in a turn-- through the shoes gripping the rotor and back into the
axle - forces across the rotor plane, unlike straight ahead braking, where
the forces are in the rotor plane)
Any experienced engineer will tell you that if there is a problem and it
goes way when you replace a part, the problem is gone.
Was the problem the root cause and will it return? Well, if it wasn't part
of the problem, the problem would still be there in some form.
However, if it is only part of the problem, the problem will later
manifest the same symptoms (E.g, if the driver brakes hard in corners, part
of the problem, the rotors will again bend/wear the faces so that in time
the plane of the rotor surfaces are no longer within tolerance, Before the
driver got in and warped the new rotors, the new rotors were just fine)
( Logically, when you change the rotor and then the problem goes away, the
problem is gone.)
and it seems
the man ought to read the specs in the vehicle manuals, which do indeed list
tolerances for rotors. And he ought to get some in depth background first.
The internet is full of half-aware self-promoters with partially applied
theories. And AMSOIL, no less.
FWIW - match mounting is a way to limit costly close tolerance machining in
many mating parts- you make hundreds of parts all alike, and then measure
them - some will be way off and get tossed, most will be within tolerance
and used according to their tolerance, and some may even be perfect. It's
cheaper than making each one perfect.
I'll put this quote from them in here for the experienced engineers to get a
chcukle
"DTV is when the rotor thickness is not the same all the way around the
rotor. DTV is typically caused by lateral runout. DTV can only be measured
with very specialized laboratory testing equipment or with special on
vehicle capacitance probes."
right.... ( or like a shop caliper or shop "mic", as noted in the
maintenance manuals.)
Quote - "This [DTV] phenomenon is what many technicians refer to as
"warping", however they actually think the rotor warped and needs
replacement."
OK, so what they are saying is that the rotor isn't warped ( and so the
rotor is true?) and the face of the rotor plane has just warped, and so they
are saying that
instead of the rotor needing replacing because the thickness varies, the
rotor needs replacing because the thickness varies and the esoteric DTV
measurements are lab things .(or you could just get refacing done at a brake
shop, if enough material is left).
enough of quoting their home-spun humor....
There are regulations - Check out the following standards for brake
materials: DE3A, BEEP, NHTSA FMVSS-105
From Toyota -
why? aftermarket pads have few, if any standards. New-car brake pads
(OEM) have to meet NHTSA standards, and thus actually do stop better, are
more reliable, and the dust around the kids and dogs is less hazardous.
nuff free stuff
I'm as fascinated as you by all the theoreticians chiming in here, but
I know one thing you don't seem to grasp, Stuie:
If you change the rotors, the pulsation will go away.
My opinion? You're shopping around for a way to blame Toyota - or
anyone else - so you don't have to spring for the new rotors.
YEA... I've been trying to figure out... is the search "here" for an
answer or is it just a debate? (In reference to the original poster).
I think a number of people have posted some clear and concise answers.
Basically you can test anything under the sun if you have the money
and time and along with that, the expertise.
Bottom line is that rotors indeed do warp, pads wear, and both need to
be replaced over time. Some rotors warp for no apparent reason, some
brake pads wear faster than others, some pads wear faster on the rear
rotors and some pads wear faster on the front rotors. Depends on the
vehicle, the brake setup / design, the type of pads / wear material,
the thickness of the rotors and the makeup of the metal used...etc...
I could go on and on.
You can find the solution you are looking for....just depends on where
you look. If you don't like the answer look somewhere else and you
might find someone with a different opinion. At least that what it
looks like to me.
I don't waste my time looking at the links to the articles. Rotors
and pads are "wear items" they don't last the life of the vehicle,
they wear out.How you drive your vehicle and how well you maintain it
play a large part in how long the vehicle lasts and how long the
brakes last.
Like I said at the start...is the search for the answer or just to
debate the issue.?
-----------
Elbert
snipped-for-privacy@me.com
I think I've found most of the answers I needed although I'm currently
working on the definition of "soap based lithium brake grease" at the
moment (mainly because the lithium appears to merely be the
saponification agent that congeals the oils used, which tells us nothing
about which oils were used in the first place).
However, my thirst for the one and true answer aside, I must agree with
you. After having read about fifty brake repair articles on the web, I
can definately agree there's a lot of bad information out there.
Witness this Edmunds article I read today (filled with errors!):
http://www.edmunds.com/ownership/howto/articles/43787/article.html
I can count more than a half dozen errors in that article. Edmunds is
doing a disservice to their clientele by publishing that article on the
web.
For example, brake rotors almost never warp. Of course, they "can" warp.
And you can get hit by lightening. But, they don't warp. What people
call warp is not warp. It "feels" like warp. But it's not warp. That
much is clear from reading scores of articles in the past week and
asking questions and reading every answer over and over and over again.
You may disagree but that's the "answer" I found in this quest.
That's why I am replacing the pads, rotors, and I will test the pistons
this weekend for sticking. I'll replace them if need be. I'm looking up
exactly how to pack the front wheel bearings at the moment. It's all
obvious to me now, but it was NOT obvious to me when I originally asked
the questions! With your help, I have arrived at the one and only truth.
It's the same with many things in life. Take that lightening bolt. I've
asked dozens of people WHY your're somewhat protected in a car from a
lightening strike. Know what almost all of the people asked said ('cept
the electrical engineers?). Like those who say brake rotors commonly
warp, almost all I asked mistakenly said what appeared so very obvious
to them - that the rubber tires "insulated" the occupants from the
lightening reaching the ground. Can you believe that? Like brakes
warping, that erroneous answer "sounds" logical until you actually
understand the dynamics of what is really happening.
Just like Galileo thought the curve of a chain hanging on two posts was
a parabala, things aren't always what the easy answer would seem to
suggest. Hell ... even the venerable Aristotle was wrong about the
velocity of falling objects but his theories held for hundreds of years
... until Galileo actually put Aristotle theories to the true test.
One reason I "believe" the articles that tell us our brakes almost never
warp is that the ones that talk about warp dont' seem to even recognize
there ia the alternate view, while the ones which propose the alternate
view always seems to know there is the prevailing presumption.
So, I pretty much have the answers to the questions posed.
There are so many more questions that I'm researching but they are off
topic for this thread.
Thank you all for helping me and the hundreds of others who read this,
Stu
On Tue, 07 Mar 2006 07:53:44 GMT, "Stuart A. Bronstein"
The FACT is that rotors "settle" or "stress relieve". What one is
supposed to do is drive their car through one set of pads, and then
get the rotors trued (read turned true) when getting the pads
replaced.
This truing should only involve the removal of enough material to
re-true the rotor. This is more prevalent a requisite in wet areas
of the world where a very hot rotor may suddenly get quenched by a
puddle or the like.
Anyway, the point is that once a rotor has been "seasoned" by said
hot quenching after a set of pads has been worn through on the system,
when it gets re-trued, it will NEVER warp again in nearly every case,
and then the ONLY time the rotor will require replacement after that
is if it gets gouged by a vehicle owner that doesn't keep his brake
system in timely repair..
In other words, if done correctly, a "seasoned" rotor will outlast
the vehicle after a single turning.
In dry areas like Southern California, where a brake system hardly
ever gets subjected to a hot quench like they do in wet rainy or snowy
areas, the rotor doesn't season as well, and may require more than one
turing to keep it true.
There is no reason to ever replace a rotor that is still above the
minimum thickness specification after a turning, and any respectable
brake shop or automotive machine shop will turn an untrue rotor first,
then check it, BEFORE suggesting that it needs replacement, and if it
does turn out to be too thin, there is no charge for the turning if a
new rotor is bought via the firm doing the turning. Also, they do NOT
ever need to be replaced as a set. The minimum thickness spec is the
ONLY spec for viability after ANY rotor has been attempted to be true
turned.
I have done this with rotors as big as the Caterpillar rotors on the
power take off of huge earth moving machinery with HUGE diameters.
True is true is true, no matter what any base level mechanic tells
you.
Oh and by the way, YES, they DO warp, and if you are a mechanic,
and have never worked in a machine shop, then you do not know.
Machined parts operate in a very specific manner. Unlike a corner in
your house, which can be out of square and still be OK, a machined
part MUST be true to its design all the way through. From your words
it would appear that you do not know anything about fits and
tolerances.
Rotors DO most certainly warp. ANY good shop knows this FACT, and
any good shop knows how to tell if one has, both on or off the car.
It isn't about alternate views, it is basic mechanical engineering,
and physics.
I welcome any rebuttals. I doubt you'll find any errors in my
remarks, however.
.
.
{{HE says.......I sez}}
.
.
==============Roy L. Fuchs wrote:{{or so he sez}}
............
............
{ I sez}
( That's FALSE info being posted in an open forum)
(Be advised....you are stating mistruths)
(You should recant now..before it's too late)
..............
..............
{{He sez}}
...........
..........
{ I sez }
{What a crock of crap}
{Again, you should recant.}
{YOU...are posting bad information}
...........
..........
...............
..............
{I sez}
{You ain't got a clue}
{You reeeeely oughta rethink this}
{You reeeeely oughta read what yer posting}
{cuz yer wrong}
...............
..............
........
........
(I SEZ)
{yer WRONG!!!!)
............
............
(HE........sez)
............
...........
( I SEZ)
(rubbish)
(you oughta pull a term of duty in icy city with a lot of stop lights)
............
............
{{HE........SEZ)
............
...........
(I SEZ)
{i ain't gonna waste my time turning a pitted, rusty, gauged, rotor
jest so's i can go call the wishfull thunk'n owner and tell em that
all his hopefull wish'n ain't done a bit a good.....HE NEEDS A ROTOR!!)
(AND.......as for yer min. thickn. spec. being the ONLY spec for
viability for replacement....well....what if, jest if, maybe, somehow,
possibly, the bearing race won't hold in the rotor....think maybe,
then, possibly, ......you might....suggest replacing the rotor then??)
(jest curious....as to yer absolutes)
(there will be a commentary at the end.....so read on dudely)
.........
.........
(HE........SEZ.....)
...........
..........
(I sez)
(I agree.....true is true)
(I do believe however, that if ANY real world, skint knuckled,
gray haired techs read this.....it's gonna be proven true that
yer not posting truths)
............
...........
(HE....SEZ)
...........
..........
{I SEZ}
(i'm a mechanic)
{in a past life...i worked in a machine shop)
(for over 3 years)
(i ran it)
(i worked it)
(i know do know)
(you have proven to "me"...that you don't)
.............
............
{HE ........SEZ}
...............
...............
(I SEZ)
(uh..huh)
(yer sounding like you don't know what you think you know
you know.........you know)
............
...........
(HE ....SEZ)
............
............
ANY..???
ok....
here we go.....
(i wood like tuh sez)
The only statement you made that sounded like anyone should listen to
is the last one. Rotors DO most cerainly warp.
So.......let me git this correct.
I stick a set of rotors on a vehical, go down the road, the
brake pedal pulsates reeeellly bad.....and i tell the customer
"Jest drive er till the pads wear out....and we'll fix er then."
git a life
git a clue
git more training
It's obvious by your post that you're extremely new to the trade,
extremely inexperienced, young as hell, or....you ARE NOT a
qualified brake technician. or, it might be all.
(want me to define qualified?????)
so....which is it.
you can pick more than one if you like.
any whooo.......
you jest posted a crock of crap.
Explain to me....what you've based the fact that wet climates
are causing a "more prevelant" "requisite" for rotors warping.
go ahead.....
i've got time....
i'm will'n to listen......
and...i'm quite eager to hear it.
now......
Explain to me.....how it is, in all your experience, that you've
NEVER...EVER..NEVER...once, put a rotor on a vehical and
found it to cause a gawd-awfull vibration right out the box.
I mean......you posting info that's make'n you seem to be
a professional with knowledge of the trade. So.....
you must check EVERY SINGLE rotor for runout straight
out the box.........right?
uh..huh
now......
Tell me.....where you read that what one is supposed to do is
"drive their car thru one set of pads".....and then git the rotors
trued on the next pad change.
I done 1 or 2 brake jobs.....or more....and I ain't NEVER,EVER,NEVER,
read.....EVER....heard that crap before.
and....i read alot.
and.....i study alot.
and....i go to classes alot.
and...i go to seminars alot.
and...i get, got, had, have, or was access to at one time.......
some of the most prominant trade mags around.
and.....i ain't NEVER...herd dat befoe.
~~In Closing~~
As far as yer..."fits and tolerances"..
listen..wakeup...slap yerself...git a new job....
git away from whoever it is feed'n you all that crap...
cuz......yer little rant on how a rotor can or cannot warp,
when it should or should not be replaced,
tolerances and fit....
well......
you've told on yerself...you ain't got enough real world,
hands on, life experience with brake service to be spewing
forth info on it.
FACT...not fiction.
you closed with..and I quote
" It isn't about alternate views, it is basic mechanical engineering,
and physics."
you were correct on 2 statements.....
rotors warp
true is true
but.......
it ain't basice mechanical eng. and physics dude.......
it's the reeeeelll world.......
go do a thousand or so passenger cars, trucks, and vans......
then come back and tell us what you know.
~:~
MarshMonster
~show hopes you don't try to tell him you been do'n brake
work for 20 years......he'll fall out his chair~
=======
=======
On 8 Mar 2006 02:18:04 -0800, snipped-for-privacy@aol.com Gave us:
I knew more about fits and tolerances and precision machining at age
ten in 1970, than your retarded ass will ever know in your entire
pathetic life, dipshit.
============Roy...Boy Toy,
go fix a Space Invader machine....
and leave all this confusing brake stuff to us Manly Men.
now .......
go along.......
engineer something......
go ahead.....
it ain't gotta work forever.....
some tech out there will FIX IT.
rotflmfao @ the PackMan technician.
hey roytoy.......you dropped yer slide rule.
~:~
MarshMonster
~slaps boytoyroy across the face with a greasy shop rag....
jest cuz he can~
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