Brakes squeal!!!!

Actually it is the internal "O" ring that pulls the piston back, not
the outer boot on most calipers.

 

thats not what chrysler taught me the oring seals the caliper

 

Yes, the "O" ring seals the caliper, but it also "bends" a but as the
piston slides though - and when the pressure is released, the "O" ring
straightens back out, pulling the piston back in just a smidge. This
gives the clearance. Take a good look at the boot, flex it around -
then try to push the piston back with your fingers. Note how little
resistance the boot gives to being deformed - and how much force it
takes to move the piston. Absolutely no way the boot could handle
pulling the caliper back.

Your instructor at Chryaler only taught you half of the story.

I've taught it too - and I've tried to get the whole story told.

 

I've used lots of cheapo chinese rotors in my cars since I don't turn
rotors, just
throw them away if they are grooved. The only difference between the cheap
chinese
rotors and the better rotors is the quality of the steel, the chinese rotors
aren't
heat treated to the point that they will stand up to a lot of heat, thus
they are prone to
warping. Otherwise the machining quality is generally very good.

However, there is a trick to using these rotors. Chinese cheapo rotors work
fine
if you learn how to brake properly. And braking properly means driving
properly.
That means when you see a stoplight up ahead, you let off on the gas and
coast to
the stop, only braking gently near the end. You don't floor it until you
get within
100 feet of the stoplight and then slam on the brakes. Another thing you
don't do
that I see people doing all the time is drive around with their brakes on
practically all
the time. I see this on the freeway every day. People nose up to the car
in front of
them until they are tailgating on his ass then he slows down a little bit
and they
have to brake. Whereas I let a good 3-4 seconds of distance from the car in
front of me, and if he brakes quite often I simply let up on the gas and
have plenty
of space to coast down until I'm matching his speed again.

The harder and longer you brake the more kinetic energy is dumped into the
brakes
and the hotter and hotter they get. And also the more fuel you waste.
Since the
average American driver doesen't appear to understand this, no wonder so
many of
them complain about warped rotors.

Ted

 

Too bad you spoiled an reasonable treatise with a foray into
metallurgy. Rotors aren't made of steel. Heat treatment isn't
done to provide heat resistance, it's done to provide enhanced
properties....and it isn't done on rotors anyway.

 

Glad you got it fixed!

BTW - the things that are being called "anti-rattle" clips (I think
that's a misnomer) are one of two types. One type is just a wear
surface between the pads and the rub points on the steering knuckle.
There is also a differenet type that is actually a pad spreader - keeps
a little spring force outward on the pads that helps retract them away
from the rotor. You can use either type, but only one type at a time.
The second type, though shown in the FSM, were not available from DC
until a few months ago - if you ordered them, what you got were the wear
bars. I'm glad they made the retractors avaialable - they are bound to
help in rotor wear and heat (warp).

So which type did you put on? To see photos, look at my third post (the
one with the photos) in this thread on the 300M Club forums:
http://300mclub.100megs42.com/forums/viewtopic.php?t=6503&postdays=0&postorder=asc&start=30
The first two photos are of the pad retractors; the second two photos
are of the wear bars.

Bill Putney
(To reply by e-mail, replace the last letter of the alphabet in my
adddress with the letter 'x')

 

Bill, I did install new Retractor Clips. I got them at my local Dodge shop.
They sell them 4 in a pack. Interesting though, it appears that they are
only used on the front, the rear did not have them.
Again, thanks for your help.
Dan

 

Very good. There never were any for the rears.

Bill Putney
(To reply by e-mail, replace the last letter of the alphabet in my
adddress with the letter 'x')

 

To my knowledge (and its fairly good...) Chrysler hasn't used a brake
system "of their own manufacture" since AT LEAST 1965, and I'm guessing
more like 1955. It as far as disk brakes go, been 99% K-H since 65, with
a few odd Bendix applications (4-piston front calipers on '67-69
B-bodies and some A-bodies) and Budd (~66 C-bodies and a few others)
over that time.

AMC used Delco Moraine, Bendix, and

Bullfeathers. GMs squealed just as much as Chryslers ever did, if not
more. Seems like every GM A-body that drove by me in the 80s (Regals,
Cutlasses, MonteCarlos" were squeaking away.

 

Yes you are right, for stockers, however:

http://www.wilwood.com/Products/002-Rotors/010-DMS/index.asp

Your right, what was I thinking! I was too caught up in the issue of not
creating the heat to begin with I'm afraid.

However, while stock rotors may not be heat treated, heat treating is
in fact, done on some rotors, see here:

From:

http://www.21stcenturymusclecars.com/brakeeradi.asp

"These rotors feature increased "mass" or "weight" in the "fire path" which
is the point of pad contact, along with curved and directional vanes,
combined with balancing and heat treating, ensure EradiSpeedT rotors "
-------------------------------------------------^^^^^^^^^^^^^^^^^^


Ted

 

I remember a couple years ago when I was toying with the idea of putting
together a "showroom stock" VW (before I figured out that I just
couldn't afford to do it right, and it would have to be my daily driver)
that cryogenically treated rotors were the, ahem, hot ticket. I'm
curious if a) anyone has any experience with them and do they live up to
the hype and b) would it be worthwhile to have a set of rotors frozen
for a regular use passenger car that has a rotor warping problem?

nate

 

I was just getting ready to post these two links in response to Ted's
post, when you beat me to it:

http://www.frozenrotors.com/

http://www.300below.com/site/home.html

I have used both their products (they both pretty much use Raybestos
rotors that they run thru their cryo process). Presently I have Frozen
Rotor (Diversified Cryogenics) front rotors on my '99 Concorde (rear
brakes on LH cars are 99% problem-free with no special efforts or products).

LH cars are very prone to brake vibration - I have many theories on why,
and not all are related to rotor warping. They actually do use cryo
rotors in racing. They wouldn't without good reason. It is clear that
cryo treatment does change the properties of metal. They prolong the
life of welding tips and engine parts (in extreme conditions).

Anyway, the Frozen Rotors apps. engineer also talked me into a set of
Performance Friction 'Z-Rated™' pads (very reasonably priced:
http://www.performancefriction.com/pages/pad_type.htm). I can tell you
that the combination is working *very* well for me (I'm presently
experiencing the longest period of totally vibration-free brakes I've
had with this car). Brakes are absolutely smooth operating. To be
honest, I cannot tell you how much pads play a part in vibration-free
brakes and how much rotors play - that gets back to my theories of the
various real-world causes of brake vibration, at least as related to LH
cars. I can say that the combination of the Frozen Rotors and the PF
Z-Rated pads has done the trick for my Concorde (80 mile daily commute).
Would I get the same results with the PF pads and non-treated rotors?
Can't say.

Bill Putney
(To reply by e-mail, replace the last letter of the alphabet in my
adddress with the letter 'x')

 

Certainly, see below.

"Stocker" is understood......I only offered the comment within the scope
of r.a.m.c. You may have noticed the inappropiate preposition "an" in my
original post...I had used the word "excellent" initially but then decided
that was going a little too far.

 

<much clipping>

me results with the PF pads and non-treated rotors?

Cryogenic treatments for steels are valid when the objective is to eliminate
retained austenite and drive the martensitic (hardening) transformation to
completion. The anture of the mechanism and to what extent it's effective
in production rotor material (grey cast iron) isn't clear to me.....

 

They claim that carbide precipitates out, with one result being
increased hardness, slower wear, and more stable and uniform structure.
Maybe that's another way of saying what you did about the retained
austenite (it's been 30 years since I had the metallurgy courses in the
engineering curiculum in which all that stuff was covered in detail).

"Anture"? Is that a typo - I'm not familiar with that word. Never mind
- just figured it out - "nature". Got it.

Anyway, you might delve into some of the technical pages on the 300
Below and Diversified Cryo sites. What I read made sense with what I do
remember from my engineering courses regarding grain structure, phas
transition, etc. You appear to have the right technical background for
critical reading of same.

Bill Putney
(To reply by e-mail, replace the last letter of the alphabet in my
adddress with the letter 'x')

 

Typos are contagious. "phase"

Bill Putney
(To reply by e-mail, replace the last letter of the alphabet in my
adddress with the letter 'x')

 

Steels and irons all have carbides in varying form and degree.
After all, the equilibrium system is iron/iron carbide.(Fe3C)

Nope.
(it's been 30 years since I had the metallurgy courses in the