My experience was Sports cars in the 70's - all discs - never had
much experience with drums other than autocross - and then the
secret was DS11 shoes on back and never-never set parking brake
after a hot run.
Downside of slots and holes in rotors is increased pad wear - but
that was the price of better braking - only place we ever had to
worry about wear was races over 4 hours.
Then you could use harder pads or just figure on changing the fronts
in slightly longer pit stop - not uncommon practice in 24 hr Daytona
or 12 hour Sebring.
Edward Mills
Antique Tractors 1930-1960
Antique Cars 1960-1985
On 2/22/2016 1:45 PM, 'Rich Barber'
c300@xxxxxxx [Chrysler300] wrote:
Thank
you. That makes sense. I always wondered what the
slots in some brake shoe linings was for—not to
mention the slots in rotors. The gas layer would
certainly affect the coefficient of friction. Perhaps
ceramic pads are less likely to outgas??
Rich
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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