[Chrysler300] Whoa, Nellie(with a proportioning valve)

["Rich Barber" <c300@xxxxxxx>]

Always interesting to read Christopher's posts.  Regarding, lost pressure
due to rubber hose expansion--the whole idea of hydraulic brakes is to
provide equal pressure everywhere in the system.  Proportioning valves are
apparently just restrictors to create a temporary and dynamic lower pressure
on (typically) the back brakes.  As there is some small flow of hydraulic
fluid on application of the brakes, all tubing, fittings and hoses create a
restriction to flow.  Rubber hoses are always reinforced, so swelling under
pressure would be minimal.  But, over time, the ID of hydraulic hose could
conceivably shrink due to rubber swelling and create a significant
restriction.

Remember, braking is accomplished by converting kinetic (moving) energy to
heat energy by the process of friction.  Front-rear balance is achieved by
varying hydraulic pressure and heat transfer rates.  More sophisticated ABS
systems further achieve balance by temporarily and intermittently reducing
and pulsing hydraulic pressure to a skidding wheel.

I don't see any significant difference in moving the two pitons in a single
wheel cylinder when compared to the two pistons in two pistons in two
separate wheel cylinders in the old MoPars--unless the shoes are improperly
adjusted.  One always notices the difference in brake pedal travel when the
brake shoes are properly adjusted.

I was taught how to adjust brakes on MoPars in the mid-50's and recall it
took extra effort, care and experience to get it right. In some ways, they
were easier to adjust than rotating the stars on the single-wheel cylinder
brakes.  These old skills are being lost as the old line mechanics retire to
their garages to work on their old 300's.  Sometimes, real friendship,
respect and a six pack will encourage one of these guys to get out and get
under.  Watch & learn.

I find it interesting that my '64K ram car has the optional 3" wide rear
drums to achieve some additional braking capacity.  I'm wondering just how
much additional resistance to fade or 60-0 stopping distance that actually
accomplished, given that the back brakes do such a small amount of braking
in a front-engine car.  I do recall that my VW's and Corvairs had much
larger brakes on the rear wheels.


Rich Barber (Bloody Yanks can ramble, also)

-----Original Message-----
From: Chrysler300@xxxxxxxxxxxxxxx [mailto:Chrysler300@xxxxxxxxxxxxxxx] On
Behalf Of christopher beilby
Sent: Wednesday, March 21, 2012 6:24 AM
To: Brisbane 300C Schleimer; cv300g@xxxxxxxxx; chrysler300@xxxxxxxxxxxxxxx;
larry@xxxxxxxxxx
Subject: RE: [Chrysler300] 1958 300D Brake shoe lining


1) Henry has thrown a bit more lght on the oddities of Chrysler front brakes
that use two wheel cylinders per wheel. Most other drum brakes used only one
cylinder - that is why on those types/them, the 'leading' brake lining
should always be shorter than the 'trailing' one - as explained just
earlier, the leading one gets sort of 'sucked on', once it contacts the
drum, whereas the trailing one never does, and has to be pushed hard all the
way/time to get same result.
 
To overcome this 'single wheel cylinder' activating two linings with unequal
application, Chrysler, and for one other, Austin Healey, used two wheel
cylinders - directly opposite each other, and in this case, BOTH LININGS
SHOULD BE SAME LENGTH - as then both will give equal stopping force/power. (
Twin cylinders were more expensive, so usually only used on higher
performance/sports models, before disc brakes replaced all drum types.)
(Rear brakes being single piston - shorter lining on front, but oddly
Chrysler looks like 'factory', both were same length!!??  And another Mopar
'oddity', adjust two front brake adjuster cams different way on fronts,
versus way you turn the rear adjusters .)
 
2) Please read this bit if not already bored to death about 300 Brakes!!?
And this brings me to another 'thought' as to why many 300 restorers have
trouble with poor Mopar/Chrysler late 50s early 60s brakes - AND THIS IS
JUST A/MY THEORY - SHOOT ME DOWN IF YOU HAVE BETTER IDEAS/THOUGHTS???
 
Critical to good/sound operation in restoring these twin cylinder per front
wheel brakes, is likely the only thing that might be different today to how
Chrysler made them ?! ANY IDEAS WHY THEY ARE SO BAD TODAY !!??
Well my 'thought' is because there are 4 front wheel cylinders, plus 2 rear,
any 'lost pressure', is multipled way beyond most other cars that only have
total of 4 cylinders ??!! Guess where I am going? I have a 300C that has
bloody brilliant brakes - rebuilt about 1982. And the flexible brake hoses
were OEM, not modern day 'often not made in USA'.
There are 3 flexible/rubber hoses per Chrysler. I recently bought a 6
cylinder 1978 Honda Motorcycle - briefly fastest bike sold. But brakes were
soon criticised. Locally there is a guy who knows, has ridden, near every
sport/race motorcycle since. He says, brakes on CBX Honda are OK IF YOU FIT
BRAIDED (stainless)  LINES instead of original flexible rubber ones. This
stops lost force/application, lost due to rubber hoses swelling.
Others may remember me earlier saying I helped a friend on his '60 Imperial
Convert - all new brakes, but at the time, the only way could get good
pedal, was when we clamped off flexible front brake hoses - so is my Honda
CBX loving 'guru' on the right thought/track, re why so many Chrysler/Mopar
brake restos disappoint - DID CHRYSLER HAVE REAL HIGH SPEC OEM FLEXIBLE
HOSES  - hoses that had zero internal swelling, unlike ones now that see
pedals go down alarmingly, give poor stopping power??
Another friend's '63 Imperial convert has brillian pedal, bleed up instantly
after master cylinder lost fluid - looking underneath, all flexible hoses
look like never changed, or if they were, it way back years ago - brakes are
great from 70 mph panic test stops.
 
So over to you '300 twin piston brakes experts' -  does the fact that in
having to apply/move 6 cylinders in stead of usual 4, make 'zero swelling'
flexible hoses super criticial/essential??!!  - (a) can my 300Cs excellent
brakes only be explained due to OEM style 'non swelling' flexible hoses, and
(b) have any overseas/US 300 owners tried braided stainless flexible hoses
before going to disc brake conversions in despair?
(These 300 brakes were not written up as useless/hopeless new, and magazine
road testers in those days drove in 'near speed limitless' days then !!??)
Does anyone know a brake hose manufacturer that can throw more light on the
topic?
 
Christopher in Australia 
Local TV tonight warned viewers to expect gas prices for Easter to bo over
$8 a gal for premium - and this for a country where a drive to any other
nearest major City is usually 450-600 miles.
Got colour/paint back on my driver 300C yesterday - questions I asked re
repaintiing it have following answers (1) OEM aerial has rubber type top
piece that has hidden threaded nut under it (2) fuzzies that sit against
side window glass are retained by metal spring clips that go into matched
rectangular slots (that have rounded ends) - not sure yet if exact same
fuzzies with exact same spaced clips are available.
 
AND FINAL NOTE FOR 300C/D restorers/users - my 300C rear side windows that
were near totally seized, non 'up or down' without help  -- PROBLEM WAS NOT
POWER MOTOR OR GEARBOX - LUBE THE TWO RUNNERS, AND ALSO LUBE THE SLOT TYPE
CENTRE LOCATER, RUNNER. Manually work/help glass up and down maybe 10-20
times, and now they go up and down like supercharged - amazing. 
 
Fixed in about 15 mins once side trims removed so could put lube on runners
wherever one can reach when in up and down positions to get the most on
everywhere
 



To: cv300g@xxxxxxxxx; Chrysler300@xxxxxxxxxxxxxxx; larry@xxxxxxxxxx
From: henry.schleimer@xxxxxxxxxxxxxxx
Date: Wed, 21 Mar 2012 20:06:23 +1000
Subject: RE: [Chrysler300] 1958 300D Brake shoe lining


  



Note that for the 57 models, the front brakes have two leading shoes. That
is, both get pulled into the drum with the car going forward. It doesn't
matter that one is upside down. The rear has leading and trailing shoes.
This gives more braking torque on the front than rear, as it is needed.
Later cars with leading/trailing shoes on the front and rear generally used
different sized wheel cylinders (or drums) to give the necessary brake
balance. Also note the 57 Chrysler workshop manual clearly shoes all shoes
front and rear have a full length lining. You could probably get away with a
shorter lining on the rear of the rear brake but I wouldn't do that on the
front as they may get hot at different rates leading to earlier fade.
Suggest you look up a 58 manual to check.

Regards

Henry

From: Chrysler300@xxxxxxxxxxxxxxx [mailto:Chrysler300@xxxxxxxxxxxxxxx] On
Behalf Of Charlie V
Sent: Wednesday, 21 March 2012 6:20 AM
To: Chrysler300@xxxxxxxxxxxxxxx; Larry Jabin
Subject: Re: [Chrysler300] 1958 300D Brake shoe lining

Not sure if 1958 shoes are any different but whenever I purchased brakes
shoes the set usually had two shoes with the lining on the Whole shoe and it
also had two shoes with the lining ending an inch or so before each end of
the shoe.

The shoe with the shorter lining goes on the front half and the shoe that
has Full lining goes on the rear half. I did an internet search to verify
this and it's shown below.

Where does the bigger size brake shoe go front or rear in drum?

The smaller shoe should go on the front. The larger shoe should go to the
rear, but not because of why you might think! 

When the brakes are applied the front shoe tries to jam itself into the
brake drum. It is that front cohesive part that has the strongest braking
force - pressing most-so upon the forward-facing shoe. However, even though
the front shoe is where the majority of braking force is applied, it does
not get the larger shoe! 

As noted, in a braking mode, the majority of the force that the decelerating
vehicle applies to the brake shoes is applied against the forward shoe by
the forward-most area of the inner brake drum, this makes the forward shoe
the stronger, braking-wise. To help even things out, the rear secondary shoe
is designed to be larger, to more equally match the braking power of the
smaller, but more powerful front primary shoe.
Ergo: The proper place for the larger shoe is to the rear.

Lion Charlie Valentine
300G, 1962 300 Sport Convertible 

--- On Sun, 3/18/12, Larry Jabin <larry@xxxxxxxxxx
<mailto:larry%40pwbsfo.com> > wrote:

From: Larry Jabin <larry@xxxxxxxxxx <mailto:larry%40pwbsfo.com> >
Subject: [Chrysler300] 1958 300D Brake shoe lining
To: "Chrysler300@xxxxxxxxxxxxxxx <mailto:Chrysler300%40yahoogroups.com> "
<Chrysler300@xxxxxxxxxxxxxxx <mailto:Chrysler300%40yahoogroups.com> >
Date: Sunday, March 18, 2012, 12:37 PM

Could someone tell me when relining the brake Shoes

Should the lining cover the whole shoe?

The reason I ask I,s I have purchased re-lined shoes from different
suppliers

>From one supplier the lining covers the shoes completely & the other there
is almost an inch at each end with no lining

Thanks

Larry Jabin

Larry@xxxxxxxxxx <mailto:Larry%40pwbsfo.com> <mailto:Larry@xxxxxxxxxx
<mailto:Larry%40pwbsfo.com> >

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