71 - 73 Brake Booster for Drum brakes

Here's how you can install a Power Brake Booster on a 71-73 Mustang that came standard with all manual drum brakes in little over an hour. I first removed the hood and hinge, however, I believe you can get away without removing these. It also helps if you remove the front drivers seat for easy access to the pedal support bracket. I also removed the carpet so that it doesn't catch on fire from the metal shavings you'll create when cutting out the plate on the firewall. Okay, now that these are out of the way, we can now begin rounding up the tools needed for the install.
1) welder ( I used a Lincoln 140 mig with argon mix)
2) Drill with 3/8 drill bit
3) Grinder with cut off wheel. I used a 4" wheel
4) 9/16 socket and ratchet with extensions
5) 9/16 open end wrench
6) dremel with small cut off wheel/grinding disc

Now lets get to work! All this can be done in any order, but here's what I did. PLEASE NOTE! Disconnect your fuel line from the tank and remove the hose from firewall to carb before attempting to use the , welder, drill and grinder in this area. Drain the lines and make sure no fuel or fumes exist.
Once the old master cylinder is removed, you'll notice two headless studs and those will need to be removed. The only way I knew how to remove these are to weld the 9/16 nut on and wrench them out and they came out without any problems. Make sure the head of the bolt and nut has a fresh surface for the weld to stick. I used a dremel to grind off the rust. (see photos)
Now you've got the four mounting holes. Enlarge these holes with the 3/8 bit so that the holes are large enough for the power brake booster mounting bolts.
Next, cut the firewall plate so that the new power brake booster rod can go through without any restrictions. Metal shavings will enter the inside cab, so be aware of any cloth or material that may catch on fire. After cutting the plate out, I then cleaned up the plate/burs with a dremel and finished with a coat of KBS 3 stage rust protection paint. You can use anything to prevent rust, like primer etc.... I just happen to have this KBS stuff on hand. Now you're ready to install the new Power Brake Booster.

Now for other parts of the conversion that may be of interest. I used a Granada Distribution block for my install and see photos of what I had to do to make it work. Do your plumbing and your good to go!
Tools needed:
1) Double Flaring tool (Quality is best, but I used a powerbuilt cheapo and it worked fine)
2) tube bender to make nice round bends, but you can use your hand or piece of different size round pipe (get creative if you don't have a tube bender) Be careful not to kink the tube or you'll need to start over again, so take your time and get a bender
3) Open end wrench = 7/16, 9/16 and 5/8
4) 1/2 socket

2 studs need to be removed


Rear View of studs under dash


Grind away rust on the tip of the stud and nut for strong weld


Weld nut to stud and now you can remove with 9/16 socket.


Enlarge the 4 mounting holes with a 3/8 bit


Cut out plate for new Power Brake Booster Rod that sits lower than manual drum booster
Clean up the burs with the dremel and apply rust protection.


Now you're ready to install the new power brake booster and power brake pedal.


Rod lines right up with a Power brake pedal.


Now for other conversion parts that may be of interest when doing a front drum to disc brake conversion on a 1971 to '73 Mustang. The Granada DBlock is identical in shape to a stock Disc/Drum 1971-73 Mustang DBlock so plumbing with OEM Disc/Drum lines is made easy.


Only Front in and Rear Out needs to have the fittings replaced.


Rear Out


Cheapo Double Flaring tool that did the job. Brake lines HAVE to be DOUBLE FLARED!



Make a clean and even cut and DON'T FORGET to put the new fitting on before making the flare!


New Fitting on


Now time to make the first flare.


Now the Double flare.


And you're good to go!


Do the same for the Rear Out


Now its time to gravity bleed! I couldn't gravity bleed the passenger front so I had my dad help me bleed the fronts the pump action style.



Drum to Disc conversion is probably the best upgrade you can make to your classic Mustang, so if I can do you it, then I believe you can to. Good luck and safe wrenching!
DJ

Good write up, two questions though. Why do some of the lines have a curly wire around it? Two; the granada prop valve looks very similar to the typical bendix style valve and has almost the same design. (refer to link below) Do you know if I could just use that in place of the heavy iron kelsey hayes prop valve that I got out of the cougar donor car for the disc brakes on my galaxie? http://www.gnttype.org/techarea/brakes/combo.JPG

Originally Posted by v8shadow

Good write up, two questions though. Why do some of the lines have a curly wire around it? Two; the granada prop valve looks very similar to the typical bendix style valve and has almost the same design. (refer to link below) Do you know if I could just use that in place of the heavy iron kelsey hayes prop valve that I got out of the cougar donor car for the disc brakes on my galaxie? http://www.gnttype.org/techarea/brakes/combo.JPG

Hey Ken,
Sorry for the late reply! The curly wires give the lines added regidity and protection from the exposed location. You can use it just as long as it matches your application, meaning if you've got Disc/Drum, then the proportioning valve needs to be for Disc/Drum. Also, since you're using a different Prop. Valve, then now you'll need to do your typical Hotrodding modifications to the lines and fittings. I almost got the same prop valve, but didn't want to do too many line and fitting mods.
DJ