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Just purchased 72 coupe. Optioned with Power Steering, AC, but no power brakes. This is going to be my sons first car. My concern is this won’t be safe, driving is a little different now than it was in 1972. I have driven plenty of cars with manual drum and disc brakes. Mostly on smaller cars and it was adequate enough to stop the car. This Mustang is heavy and having never driven one I was thinking this might be more than he can handle. Everything brake wise needs replacing, so now is the time to do it.

So, for those with manual brakes, should I keep them and save some money or do a power disc swap on the front.

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Power disc for sure. I've had manual drums. They absolutely suck and considering how many modern cars can stop way faster, he will probably get stuffed into the back of a 20 year old Hyundai.

Stock Mustang parts with good quality shoes, pads, new drums and rotors (nothing turned, all fresh) will do well. 

But to be safe, new springs and shocks are required to get the most out of the brakes. Worn suspension just means the brakes will lock up the wheels on a rough road or due to nose dive.

And good quality tires. I don't care about the raised white letter muscle car look, I prefer tires that grip in all weather and respond.

If safety, effectiveness, and predictability are what you want, then you have to look at brakes/suspension/tires as a total system.

 

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My 71 had manual drums when I bought it. Drums can be rebuilt to work pretty well, but I wanted to go disc simply for personal preference. I decided to do a front disc conversion, but remain manual. I did this primarily because to do a power swap, you have to modify where the booster bolts to the firewall (its different on a power vs manual car).

There are good front disc conversion kits from Summit, Pirate Jack, and others. Almost all do not come with a master cylinder, which is a requirement.

After a lot of research, I learned that many people pair a manual front disc setup with a 74 Maverick master cylinder that was designed for a manual disc/drum combo, and an adjustable proportioning and residual valve spliced into the rear brake line feed. I sourced an MC from Rock Auto for a reasonable price, and Jegs has several easy-to-use valves.

You can do the splicing from underneath, or in the engine bay. I found it easier to do it under the car near the rear axle. Make sure you still go through the rear drums and set them up correctly, and read the prop valve instructions. This overall setup works really well.

Once done, the effort to stop isn't much different than a power setup - and it was less overall work and cost than a full power swap. Just something to think about.

Edited by 71coop

Black 1971 Mach 1

351C/FMX/TrickFlow Heads/Lunati Retro Roller Conversion

Classic Auto AC, Manual Front Discs, Upgraded Springs/Shocks/Close-Ratio Steering

 

IMG-2977.jpg

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I agree with 71coop. My 71 Mach1 had no power brakes or steering. It was a handful to drive amongst modern cars and their less than caring drivers. 

I opted for SSBC 4 piston Kelsey-Hayes style disc brake conversion. This kit came with disc/drum m/c, adjustable rear brake bias valve and everything needed for the swap. However, I'm not sure if this kit is still available as I think SSBC is out of business or been bought out. There are other conversion kits out there at reasonable prices. For about 5 years, I ran these brakes manual until I finally took the time to add the 11" booster. This is NOT an easy job by a long shot. It required stripping out the column and brake pedal bracket. However once done, I was sort of disappointed that the increase in stopping power was not as pronounced as I'd hoped for. This has been written about many times here. Also, while you're in there, replace ALL your old brake lines, back to front. Again, I opted for preformed SS lines, but they are harder to work with. Good quality steel lines will be fine. Bottom line is the underside of the car is far more important than the way it looks on the top side.

 

Edited by Stanglover
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Geoff.

 I learn something new every day!

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  You could look for a donor car to pull the spindles and  brakes from to use.  Would make for getting parts a little more easier to obtain locally than having a specialty after market kit. During my rebuild I went ahead and replace all the brakes line. My car came from the factory with all drum manual brakes. When I went to change the pads that's when I found out that they were not the original.   Somewhere along it's journey the front was swapped out for disc and  a power booster was added.  It became a guessing game as to what I needed to buy since I didn't know what type of car the calipers and pads came from.  After popping open a few dozen boxes of calibers at my local PepBoys to try to find a match I struck gold. Was able to the determine that rotors, calipers and pads are a match for a  76 Granada.  They did a descent job adding the power brake booster and new master cylinder.  Brakes work great. 

Edited by Kilgon
Change word from drum to rotor.

Kilgon

 

 

"The only dumb question is the one not asked"

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I did not know the firewall is different between manual and drum. That could change the equation.

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Drum brakes get a bum wrap because people do not know how to do a correct full job when they rebuild them. I put together a how to and added links to some video and info I think is good. The contact area of drum breakes is more than disc and will slide all four tires easily so disc brakes are not going to be a leap across tall building in a single bound. Disc is better for repeated hard braking, yes but not really a huge leap otherwise. It is cheaper to build a car new with disc brakes but the up charged people making them think it is all much better.
I just last week got a brake shoe grinder that I have been looking for a long time. Yes you can go to E-bay and buy about anytime for $800 but I needed a deal. Got a Ammco 8,000 grinder that will do about any car or pick up drum out there for $150. Go through the info if you cannot locate someone near you if you measure your drums send to me and I will grind to proper fit. I have to clean it up and will start maybe this afternoon.
I ran drum brakes for years and kept mine adjusted to the point you could let go of the wheel and slide the tires and steering wheel not turn.
I do need a drum micrometer if anyone has one cheap will come up with just calipers is nothing else.
The file should open and have some links to some good video and info so you understand why just putting new shoes on is not a drum brake rebuild.
 

Drum_Brales.xps

When a man is in the woods and talks and no women are there is he still wrong??:P

David

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3 hours ago, Kilgon said:

  You could look for a donor car to pull the spindles and  brakes from to use.  Would make for getting parts a little more easier to obtain locally than having a specialty after market kit. During my rebuild I went ahead and replace all the brakes line. My car came from the factory with all drum manual brakes. When I went to change the pads that's when I found out that they were not the original.   Somewhere along it's journey the front was swapped out for disc and  a power booster was added.  It became a guessing game as to what I needed to buy since I didn't know what type of car the calipers and pads came from.  After popping open a few dozen boxes of calibers at my local PepBoys to try to find a match I struck gold. Was able to the determine that drums, calipers and pads are a match for a  76 Granada.  They did a descent job adding the power brake booster and new master cylinder.  Brakes work great. 

 

Funny, I had the exact same experience with my front disc brakes. None of the 71-73 Mustang brake parts fit. I didn't know granada swaps were a common upgrade until much later.

Nowadays it's hard to find the spindles to do that swap though, so it ends up being fairly expensive. Probably for the better though, since there are better more modern kits on the market now.

Plain Jane | 1971 F Code Coupe 302/C4 Automatic

Goin' to Town Rig | 1971 F100 Ranger XLT LWB 390FE/C6 Automatic

Commuter | 2018 Tesla Model 3 Midrange RWD

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56 minutes ago, detritusmaximus said:

I did not know the firewall is different between manual and drum. That could change the equation.

  This will help. The pic is a bit blurry because it's heavily cropped. The red arrow shows the existing (two) lower bracket mount bolts that have to be removed and the hole drilled out to 3/8". the blue arrow is the cover plate and the green arrow is the M/C mount that also have to be removed and drilled out. The second pic is what it will look like after this work has been done. If I remember, I had to change the opening size and make a new cover plate, but the memory is getting bad. That of course was to install a Cardone reman 11" booster. I believe you can use a 9" pancake type booster, but the 8" Bendix won't fit if your car has shock tower braces. I know, I tried.

IMG_2856 (3)_LI.jpg

IMG_0603.1.JPG

Edited by Stanglover
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Geoff.

 I learn something new every day!

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Okay, that makes sense from an engineering stand point. If they made that size hole on all, not just power boosted cars, then that area would be weak and probably flex or crack.

On my Opel Manta you can see the firewall flex even with the power discs. Many racers have reinforced the area behind the booster because of cracks due to 'over eager braking'.

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