A significant factor in racing at least in olden days was outgassing
of the pads / shoes. Phenolic resin or similar binder materials
tended to offgas when hot - 350F and above for phenolics. That built
up a cushion of gas leading to spongy pedal after repeated heavy
usage without time to cool sufficiently - hence the addition of
cooling holes and / or slots in rotors and addition of slots in some
pads.
Edward Mills
Antique Tractors 1930-1960
Antique Cars 1960-1985
On 2/22/2016 12:48 PM, 'Rich Barber'
c300@xxxxxxx [Chrysler300] wrote:
Now
this is important. Brake fade exists on drum and disk
brakes and I have always thought it was about the
coefficient of friction between lining and drum or
disk diminishing at high temperature.
It
is rather amazing that the tremendous kinetic energy
of 2 ½ tons of mass at high speed could be so quickly
converted to heat at the relatively light drums or
disks and wheels and be transferred to the surrounding
air. The hot drums or disks are also transmitting
heat by radiation to their surrounding environment.
The big aluminum-finned Buick drums were impressive.
I
recall a comment by a Chrysler 300 racer that he only
had two stops in the brakes—but only usually needed
one—at the end of the race. I also recall seeing a
’55 or ’56 300 on a track being hit from behind hard
by a Ford. No explanation as to why the Chrysler
stopped on the track. Embarrassing and could lead to
whiplash, ruptured gas tank & fire.
Rich
Just
curious...doesn't brake fading refer to the
expansion of the drum due to heat ? So calling
linings 'fade resistant' may not be a correct
description.
The
late Neil Vedder used to talk about a company
called Firm-Feel for relining brake shoes. Has
anyone had experience with them ?
-----
Original Message -----
Sent:
Monday, February 22, 2016 12:51 PM
Subject: Re:
[Chrysler300] Magnum Force disc brake
conversion
Regarding the drum brakes
on the early 300's, I had an excellent upgrade
through Porterfield in California. I had the
drums ground out just enough to remove any
grooves or irregularities, using the local
NAPA store. I measured the exact diameter of
each drum with a large digital caliper and
shipped out the old brake shoes, taking care
to mark each one so they could be dedicated to
the correct (resurfaced) drum. Porterfield
installed new linings with a modern
metallic/ceramic compound they call R4D, which
has not only excellent high-temperature fade
resistance, but also very good initial "bite"
when cold. Using my measurements of each drum
diameter, they custom-ground (arced) each shoe
so they could mate with the dedicated drum.
Sent from my iPhone
Bob:
Ten years ago I
was able to get the new shoes on our
’55 C-300 ground at Clutch and Brake
Xchange in Stockton: http://clutchbrakexchange.com/
Had to, the drums would not go on over
the new shoes. I took the drums to
them after a very light cleanup cut on
the drums. Worked very well with
occasional adjusting for wear.
Rich Barber
The
brakes on my 300G are bone
stock and I plan on keeping
them that way. The shoes were
replaced back in the '70s when
you could still get shoes
arced, and the wear on the
shoes at this point is maybe
25%. I do adjust them every
couple of years, I don't drive
it much, and I purge the brake
fluid about every 5-7 years
using silicone fluid. The
master and wheel cylinders are
all brass sleeved. The car
stops straight, no pulling,
and has adequate stopping
ability even from freeway
speeds at the off ramp. The
only issues I have had are
from brake fade, like when
driving back from Reno, West
bound through the Sierras,
they can get a hot and fade.
I suspect this is less of a
problem with a G than it would
be with an F because the G has
15" wheels and vented wheel
covers.
My
interest in disc brake
conversion kits is not for my
own car, but rather those that
contact me with questions
about converting their 300G or
similar car to discs. They
want a modern brake system in
a box that shows up at their
doorstep and can bolt on, I
get that. Also, many want a
dual master for redundancy,
and that can be very
challenging with a ram
manifold. Another alternative
I have heard of is to convert
to later Bendix self
adjusting, self energizing
types like those used on '63
and later. I've read they
work pretty well and are not
as drastic a conversion
process, but you need to
source the parts carefully and
probably used.
I guess
what I'm saying is that if it
ain't broke don't fix it, but
if you do fix it, fix it
right!
Right on Andy..this year getting
into these pretty
good. As much
understanding the
technology --and the
why , as any repair
effort. I am so
impressed with the
300B winning like
that, over and over,
in Nascar on these
brakes. Fact. Almost
5000 lbs on NASCAR
tracks at 100 mph for
hours? Yet “bad
brakes”?
We should have asked Vicky about
this!! Maybe we can!
But, like many of us in the
past, first thing I
did many years ago,
was take the brake
drums to the local
auto machine “to turn
them” and then buy
“new shoes”. Most of
my grief was started
right there ; the
shoes and drums were
different sizes!. That
simply will not work
with these brakes. Not
even close. The
carefully and
beautifully designed
dual self energizing
fronts depend on
precise diameter fit
360 , for the degree
of self energization
they exhibit.. It can
go either way from
weak brakes that
barely stop the car to
erratic violent
grabbing. But not
knowing that , at the
time, and thinking
“they will wear in”
led to thousands of
miles of grief,
hundreds of
adjustments etc
etc..and occasional
lockups,-- so one was
soon getting afraid of
what the car might do.
Who needs this, starts
up. Why the 68 discs
on the 57 Dodge. ( has
a 480” 440)
That grief leads to metallic
linings, riveted vs
bonded , new drums,
all that stuff. Waste
of time. Each time you
go new on the shoes
you reset the “fun
party” miles to zero.
I am convinced, and it
is just my opinion,
that turning drums
that are round , no
matter the grooves etc
hurts them a lot in
2016,--- if you have
the matching half worn
shoes reuse them. .
.Mass is gone, by
grinding (fade!) they
are more prone to warp
(weaker structurally)
and they are the wrong
size . And many of our
drums, the 12” ones
have probably been
turned several times
trying to fix “bad
brakes” . And that
positive experience I
had with brakes
working fine for 50k
from new in
1960,---and you saying
100k off a set put in
correctly on a G just
affirms all this.
George said the exact
same thing..but often
not as nicely (smile)
. None of his cars had
disc brake upgrades,
although if he had
done so he would not
tell you, and
probably paint them
with a cover to look
like rusty drums. (I
miss George..that cam
is stock,
John---honest).
The new 300G tests in 61 reflect
what they do new. When
put together right.
Thanks Andy!
Yes,
John, I agree. One of
my mechanic mentors
who opened a service
station in 1957 always
told me the problem
with these brakes was
with the mechanics and
not the engineers.
He
always arc ground. (In
fact, I have his arc
grinder now.) The
linings he ground for
me in 1990 are still
on my G after 100K+
miles.
Other
things I have
published in the club
newsletter the newbies
wouldn't have seen:
Paul
Mallwitz, a Chrysler
engineer who spoke at
a club meet in 1982
was asked: "How did
you get the brakes to
work on these cars?"
Reply:
"With great
difficulty. Those
Center Plane brakes
had to be put together
like a watch in order
to make them work
properly."
Next, in the April
1961 issue Motor Life
magazine tested a
300-G and recorded a
60 to 0 of 131 feet.
That's average for
today's cars. Mistake?
Don't think so. Dart
D-500 in the same
issue: 125 feet!
Other
cars in the same
issue:
Daimler
SP-250: 194 ft. (2090
lbs. with disc brakes)
In
a swiftly warming
Chicago
Just a FYI<
A lot of the fitment differences
for a total
upgrade are
because they
changed at
various times
the lower (at
least) ball
joint OD , how
it fits,
(press or
screw in to
lower arm) and
the size of
that ball
joint taper
that goes into
the steering
knuckle. I
know it was
long ago,
details not
100% clear
tonight , ,
but I put
67-68 Dodge
police car
package
steering
knuckles,
discs and
ball joints
into 57 Dodge
control arm by
reinforcing
the end of
lower control
arm with added
ring of 1/4”
steel and then
boring that
out for what I
think was the
larger (than
57) 67-68
lower ball
joint. I think
top 57 one fit
the knuckle or
spindle ok, or
found one that
fit. . That
let us put on
stock 67 or 68
police car
disc brakes,
the “big
discs”-- hot
set up long
ago --before
disc kits---
on 57 Mopar.
Now they have kits that fit the
old
knuckle…and
leave the
small ball
joints. Two
kinds of
kits??
..special
adapter
knuckle-- or
not . By way
of awareness,
not comparing.
But insight
into why some
years and not
others.
This change to discs on my 57
was made ,
really,
because I had
frankly
screwed up
more than one
total contact
brake setup,
through not
knowing what I
was doing,
after buying
all new parts,
, and was fed
up with “all
the problems”.
They are real
problems.
But is it
the brakes?
I had a brand new 60 dodge , in
60, manual
brakes ,
bought then
because I
liked two
leading shoes
on the manual,
had heard and
seen many
horror stories
about power
brakes in
general 55-60,
--60 Dart was
a great set
up! I beat it
unmercifully.
It was perfect
in every way ,
brake wise;
used to laugh
at best
friend’s GM 57
Pontiac power
brakes with
on-off feel.
Beating
unmercifully,
was street
drag racing
several nights
a week to 100
mph + ,=
going was the
problem, not
stopping. No
pulling no
grabbing..
The basic torsion bar suspension
design is
about the same
across these
years ; all
this by way of
info, not
advocating
doing it, but
good to think
or know about.
.
Do you need discs?? Sort of
falls out of
it? Idiot
proof as far
as assembling
the pads….
I am in the middle of doing some
discs, but
still
ambivalent.
Not if drums
are working
right, is one
answer. They
worked right
at the
beginning.
Also looking back, many of the
problems with
total contact
, or other
Chrysler
brakes are
errors caused
by experts
(who are not)
in putting
them together
right,
especially
arcing the new
shoes to a
turned drum.
If you do not,
with all new
parts, the
brakes do not
work. Discs
get into
front/rear
balance,
another
possible can
of worms,
despite that
balance
“valve” . They
have
inherently
different
actions..
They won all those NASCAR races
with them,
stories about
“fade” on the
street leave
me cold. Worse
than fade---
-------if the
shoes are not
touching the
drum , most of
the way
around!
Sure , not as good as modern
discs, but
awfully good
brakes.
Did you know GM put MOPAR total
contact brakes
on the racing
Corvettes with
Buick drums
about 1960??
they watched
the 300B race,
brakes and
all, and win .
. So would I.
On a light
corvette?
Bulletproof .
And the
“fading after
3 panic stops
from 120+ mph”
in
contemporary
300 tests is
not exactly
how we use our
cars today.
What reminded
me of all that
, was seeing
that 300B race
clip a few
weeks back ,
on this site .
No disc
conversions ,
yet racing
competitively
for real, in
2015? Braking
hard on
corners over
and over…..
(he did have
Buick drums
too..which
have aluminum
fins on them.
60 to maybe
62. That
forces a wheel
change too ).
Before discs,
that was the
hot setup.
Rods,
Bonneville etc
. The brakes
we take off.
My problems with these brakes on
300F over the
years was not
fade..they
were pulling,
grabbing, low
pedal , poor
stopping rate,
squealing etc
etc . 300 B or
60 Dart was
not like that
…. Why?
Just sayin….there is a
disconnect
here
somewhere.
Others see it?
John
I sent them an email. I'll report back with what
they send me.
Bob J
From:
John Nowosacki
[mailto:jsnowosacki@xxxxxxxxx]
Sent:
Wednesday,
February 17,
2016 1:22 PM
To: Bob
Jasinski
Cc:
Chrysler 300
List
Subject:
Re:
[Chrysler300]
Magnum Force
disc brake
conversion
pictures
say 57 to 61,
but when I
click on the
link for
picture or
part number,
it says 65 to
72?
__._,_.___
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