Manual To Power Brakes
Here is an option that many drivers take for granted today. The
application of engine vacuum to braking power allows the driver to press the brake pedal
with less effort, and still maintain the same, if not better, braking force. With the
early Falcons being the compact cars that they were, not much room is available to squeeze
a booster and master cylinder into the cramped area between the firewall and the driver's
My Opinion of this System
I, like many of you, am the skeptical type. I liked the idea of having power brakes,
but off of a Geo?! Will it work? Can it actuate bigger brakes than it was matched to?
There has to be brake fade, right? Maybe impossible bends needed in the brake lines to it?
1.) You need to slightly modify the shock tower to firewall brace to fit the unit. The
original instructions given to me on this swap call for "massaging" the brace
with a hammer to gain clearance. I opted to cut a semicircle out of the brace, which you
will see below. The necessity of modifying the brace depends on
what angle you mount the brake booster at.
The steeper the angle, the less necessary the brace mod.
2.) I am picky when it comes to brakes. I like a certain feel to them. This setup has a small master cylinder bore, 13/16", compared to the Falcon stock 7/8", or the 1" bore of the Falcon optional power brakes master cylinder. The Geo unit does work, stops the car smoothly and evenly, and locks all four tires in panic stops. The only thing I don't like about them is the feel. It is a "soft" feel. The brakes begin to grab about a 1/4 of the way down, and I can lock them about 5/8 of the way down, but the pedal is too easy to push in my opinion. This "soft" feel, at least for me, had me stopping hard the first couple of times out since I hit the pedal expecting more force would be needed compared to what I truly needed.
Here we Go.....
1.) The 89-94 Geo Power booster and master cylinder are unlike American counterparts.
This is a foreign part, and it has many differences compared to the typical Ford or Chevy
master cylinder or booster. The master cylinder and the brake reservoir are separate
pieces, with the reservoir being a tall cylinder with a screw off cap. The brake failure
warning light is situated inside the reservoir, so plumbing of a switch is unnecessary. A
simple plug comes off the reservoir to power the switch, and can be seen in the pictures
of the unit below.
The Geo unit here is next to a 1967 Ford Mustang dual master cylinder, the unit that was on my car before this swap. Look at the difference in size. They're pretty close, eh?
2.) This system can be installed into 1963 1/2 to 1970 Falcons. As of yet I have not
heard of this unit being installed into a 1960-1962 Falcon.
3.) I followed the instructions sent to me by the fellow discussion group member who
discovered the compatibility of this unit and installed the Geo unit on his Falcon. Many
thanks, Mark. The instructions posted here are his original directions, with some
of my additions and modifications.
The top left photo shows the original master cylinder removed, and the paper template described in Mark's directions taped in. With the help of my father, we used a grinding wheel and metal cutting hole saw to enlarge the original master cylinder's hole, as seen in the top right photo. The bottom photo is showing the use of the grinding wheel to clean up the semicircle I cut into the brace. I wasn't too worried about aesthetics here because I am replacing the original braces with a custom export brace. This is the main reason why I didn't take more time in seeing if modification of the brace was necessary.
After the hole in the firewall and the trimming of the brace, I installed the Geo
booster/master combo. One of the most important things one must do when installing a
master cylinder is to bench bleed it. There are generally two ways to do this: with the
master on or off the car. I prefer to bleed the master while it is installed. Before the
brake lines are connected to the master, go to the auto parts store and buy a master
cylinder bleeding kit. It is simply plastic fittings that thread into the master with
hoses that are placed into the reservoir. By pumping the brake pedal, all the air is
expelled out of the master and fresh fluid fills the space. The bleeding kit is seen in
action in the left photo.