Re: [Amc-list] rear wheel lock up problem still

["Swygert, Francis G MSgt 436 CES/CECM" <Francis.Swygert3@xxxxxxxxxxxx>]

In my long winded post on brakes, I forgot to mention changing the rear
wheel cylinder size!! Thanks Tom J, for posting that!! 

Check your TSM, Dave, for the wheel cylinder size. Americans typically
used a 1/16" smaller wheel cylinder. Wheel cylinders have the opposite
effect as master cylinders. They operate on the total amount of surface
area that has pressure applied, so a large diameter wheel cylinder has
more power than a small one, though it takes a slight amount of
additional volume to move it as far. Again, this can cost a little --
you have to move in 1/16" increments. In your case a 1/16" smaller one
will probably do the trick. 

I'll have to check my TSMs when I get home to give a recommendation. All
but a few years 63-66 AMCs used Bendix brakes, so interchangeability of
the wheel cylinders is excellent. Some 63-66 models used Wagner brakes,
whose parts DO NOT interchange with Bendix. I'm not 100% certain of the
years and models, but Matt Haas has some experience with them. All
Bendix interchange in my experience, though some filing of the mount
holes in the backing plate may be needed for a good fit. I seem to
recall doing that at one time or another, but can't recall the exact
application. As long as the wheel cylinder is centered everything should
be fine.

I'll note one more time -- make SURE you've thought everything out and
UNDERSTAND the impact of what you're doing. TESTING IN A SAFE
ENVIRONMENT IS A MUST before normal driving. Find that wet parking lot
or dirt road with no one else around for testing! KNOW HOW THE CAR
REACTS TO THE CHANGES before getting out on the road!

I had the opposite of the experience you're having with one of my
Americans.  I'd installed bigger drums from a 64 Classic on the front,
wheel cylinders and all (my first brake swap). The fronts were a bit
touchy until I put the 1/16" larger wheel cylinders in the back from the
Classic (with the smaller American drums and shoes -- IIRC the Classic
six just had 1/2" wider drums). Braking was much better then since the
rears were doing a little more work and relieving the fronts some -- at
least that's my theory. All four would lock if you really laid into it,
but stopping power was increased to the point that really wasn't
necessary. Never had a problem even in ice, but I knew not to hit them
to hard. Since I was the only driver, it wasn't a problem knowing the
car's habits. I wouldn't let others drive it in bad condition, not even
the "bestest" of my friends, even with me in the car with them. It was
rare anyone else drove the car even in the best of conditions without me
in there too!  
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