An early Mustang with manual drum brakes is a death trap. Convert
to front discs and the situation becomes slightly better, but
still resembles a coffin on wheels.
I know that the more mods I make to increase the power of
my '67 coupe, the more weary I become about being able to
confidently bring the beast to a stop. A few years back the
pathetic front drum brakes were replaced with the cheap and
effective "Granada" disc brake conversion (look
for a "how to" article soon.) This improved the
situation considerably, but the effort required for manual
brakes becomes a chore, especially if you frequently drive
a newer vehicle with power brakes.
Therefore while the motor was out for rebuild, I decided to
step up the safety margin a few notches by installing a power
booster kit. The results have been simply amazing, and it's
hard to believe that a car so old can feel so new and safe.
The days of driving 20 car-lengths behind the car ahead are
over.
While Ford did offer power assist brakes on the 60's Mustangs,
it was a costly option that most people simply didn't opt
for. The result is that enthusiasts, like you and I, have
high horsepower Mustangs that can't stop on a dollar bill,
let alone a dime.
Fortunately because power boosters were a factory option,
the cars are ready to accept one without too much fuss. There
are some required modifications to the firewall and pedal
assembly, and it is necessary to replace the manual-brake
pedal with a longer power-brake specific pedal. Failure to
install the power brake pedal will result in poor pedal ratio
and ultimately less than optimal braking. There will also
be a clearance problem with the pedal pushrod and firewall.
Required Parts
You can purchase a replacement 65-70 brake booster and install
it using the instructions shown, permitting that you find
a power brake pedal. Or you can purchase a kit from Master
Power Brakes which includes as much or as little that you
desire in order to complete the swap. The kit I used (MP Brakes
part number BM1521KS) came with a 9" dual diaphragm booster,
a new dual resivior master cylinder, and a new reproduction
power brake pedal for manual transmission.
Booster and Master Cylinder Issues
Note however that the 9" booster was never a factory
option. Mustangs through 1970 used an 8" single diaphragm
Bendix or Midland booster. The 9" booster fits fine,
is actually more compact, and will work better due to its
larger size and up-to-date design. However we did run into
a clearance problem with the clutch cable conversion kit we
planned to install. Because the cable clutch conversion was
a top priority for our project, we were forced to purchase
and install a rebuilt 8" original style booster. We'll
show you both installations later in this article.
Also keep in mind that the smaller engine compartment of the
65-66 Mustangs prevents the installation of a dual resivior
master cylinder and the 8" or 9" power booster -there
simply is not enough room between the firewall and shock tower.
MP Brakes offers a 7" compact booster which will fit
in the 65-66 engine bay with slight indenting of the shock
tower to accommodate the dual reservoir master cylinder. Don't
be tempted to just maintain the "mason jar" single
reservoir master cylinder. The dual reservoir master cylinder
will ensure your have at least one set of brakes should either
the front or rears fail.
1965-1966 Mustangs only have about
15" from the firewall to the shock tower, making
it tough to squeeze in a booster and dual reservoir master
cylinde. MPBrakes offers a kit with a 7" booster
and dual reservoir master cylinder (right) which will
fit with some hammering of the shock tower. |
Installation
Plan to spend a full day installing the booster. There will
be a need to bend and fab up new brake lines as the master
cylinder will be a good 6" forward of it's initial position.
This isn't too tough considering the brake lines and fittings
are standard off the shelf items. Continue
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