IML: Total Contact Brakes

["Burton Bouwkamp" <northburt@xxxxxxxxxxx>]

Steve B

I was a Chassis Engineer at the Chrysler Jefferson Plant when we brought out 
Total Contact brakes. I don't remember the year but I was at Jefferson from 
1952 to 1960 so it was during that time.

Total Contact brakes was a great design concept of the shoe web floating 
between two alignment plates - BUT brake squeak was a big problem. To solve 
that problem we added raised spots on the backing plate to touch the side of 
the shoe The principal was to act like a finger against the side of a 
vibrating tuning fork. To be effective in eliminating noise we had to raise 
the lands on the backing plate so high that we cocked the shoe and 
compromised the "total concept" design principal (it meant something had to 
deflect on brake application for the shoe to align itself with the drum). 
The backing plate to shoe interference also adversely affected shoe 
returnability. In summary we solved the noise problem but compromised brake 
actuation to do it. That's when we decided to join the rest of the industry 
in using the "Lockheed" brake design.

You are right that we had a brake problem with 14' wheels on the 1957 
Imperial. Field experience in the mountains and hilly urban areas was a big 
problem. We went to 15" wheels, ventilated wheel covers and redesigned drums 
to improve brake cooling. Those changes did not get into production until 
early 1959.

Burt Bouwkamp


---- Original Message ----- 
From: "Steve B." <Imperial59@xxxxxxxxxxxxxxx>
To: <mailing-list@xxxxxxxxxxxxxxxx>
Sent: Sunday, December 09, 2007 9:22 AM
Subject: RE: IML: After a Long Silence


> >The first question really is, however, with modest driving, is it 
> >possible
> to get the factory brakes >to be reliable without constant fiddling and
> adjusting.  I've heard stories of these "total contact" >brakes being very
> fussy, especially on Plymouths and Dodges etc.   I won't need extreme 
> brake
> response >as I will drive the car gently anyway.   My car is really in
> excellent condition as it has only 25,000 >original miles and has been
> treated well all it's life.  The biggest brake problem to date has been
> > hydraulic leaks at the wheel cylinders.  Some of the problem surely has
> been due to non-use and that >condition will improve now.
>
> Are you still running the 14" wheels?  I recall a recent conversation 
> where
> someone was having clearance problems with the AAJs and the 14" wheels.
> Don't recall what became of the situation but a good archive search on the
> website would probably turn up an answer.
>
> Mid year '59 Chrysler changed to 15" wheels with slotted wheel covers for
> better brake cooling.  At the same time they increased the size of the 
> brake
> shoes and changed the cooling fins on the drums.  This tells me that even
> they knew there were heat issues with the brakes and were trying to 
> resolve
> the problem doing the best they could with what they had at the time.
>
> My '59 is still all stock on the brakes and was completely rebuilt about 7
> years ago (my how time flys).  In that time I haven't had a single problem
> with the brakes.  I have adjusted them one time and I flush the fluid once 
> a
> year because I live in the land of 100% humidity (and I would do that with
> the AAJ too).  I don't drive the car a lot but I have taken a few 1200+ 
> mile
> trips with it along with the Sunday beach cruises and never had an issue
> with the brakes.  To me that have been very reliable.
>
> That's the good part.  The bad part is that, as you know, they don't stop
> like a new Toyota.  I find that mine handles one panic stop great, the
> second time ok but not as good and the third time you better stick your 
> feet
> out the door.  Once the brakes have a few minutes to cool off they are 
> good
> as new again.
>
> If the brakes ever give me trouble again I will probably change over to a
> dual pot master cylinder for safety but for what I use the car for I can't
> see the AAJ conversion being worth the trouble.  I sure wouldn't consider 
> it
> if you are just doing so for increased reliability.
>
>
>               Steve B.
>
>
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