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What I learned converting to power front disk brakes.


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Things I learned converting my 1971 mustang from manual drum to power front disk brakes.

 

I choose to go with a stock front disk brake setup. So I purchased a used set used front spindles from a power disk car. The setup came with the disks, calipers, spindles, master cylinder, proportion valve, and power booster.

 

Here are the new parts I purchased.

Rubber brake hoses

Disks

Rebuilt calipers

Bearing seals

Brake pads

And a rebuilt brake booster

 

Now here is what I learned. The manual drum brake car has several more different parts from the power front disk car. The first one I learned about is the brake lines. The location of the steel lines almost requires you to purchase new lines. My suggestion is go ahead and put that purchase in your budget. Again the location of the brake hoses to the calipers makes this a difficult if not impossible, but when you change the master cylinder and and the new proportioning valve you will be glad you have the hard line kit.

 

Parts I purchased later:

 

Disk Brake pedal

Stainless hard line kit

 

Next fun bit of hardware. The manual drum car uses a different brake pedal for the power assisted disk brake car. The leverage used is different and the master cylinder mounts higher on the firewall. I located one on eBay and sold my other. Not a bad exchange.

 

Now that I have brought up the firewall, you will need to relocate the hole the master cylinder bolts to. It's not too bad of a job and diagrams are one the web. The way the power booster mounts is different from the manual brake master cyl.

 

Now once you relocate the hole, charge the brake pedal, and run new hard lines and mount the new proportioning valve. The rest is a snap. Knock your ball joints loose replace the spindle, and from there is is like a brake job.

 

It did take me a while to stop the brake fluid leaks from the new hard lines. I ran stainless steel and they are a pain to stop from leaking. But once that was stopped the brakes work like a champ.

 

I know there are other kits and other disk conversions, but this was the rout I went. Best of luck. I will try to add some photos.

 

I did find a really good deal on the power booster from O'Reilly on line. It is not the correct part for a concourse restoration but it was only $100.00 and shipped free to my local store.

 

 

 

 

 

 

 

 

 

 

 

 

 

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Looks good. I did the same swap on my manual drum brake car, but I did not go with the power brakes yet. I am still running the manual disc brakes now. I have the brackets, pedal, master and booster still in the garage. Maybe someday I will get to it!! I got all my parts off a 72 convertible.

The hard lines from the drums will work down at the calipers with a little tweaking. I am planning on swapping all my stuff to power disc later down the road, so I will end up going the route you did with new lines made for power brakes.

Nice job and keep up the good work!! Heres what mine looked like installed!

 

av5rn6.jpg

1fk3zt.jpg

Kevin
1971 Mach 1

408C Stroker - C4 w/3,000 stall - 8.8" Rear w/3.73's - Disc brakes all way around.

 

 

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Good write up and lessons learned for others. Even better safety upgrade.

BKDunha

72 Mach 1 H-Code (Concourse driven restoration)

67 S-Code Factory GT with 4-Spd

68 Mercury Cyclone (Pro-Street project)

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Pastorpat, I too have done this dance. It has been posted on before, but it seems you have a pretty good handle on it from your own experience.

The swap from drums to discs isn't that hard. In my case I went with SSBC Kelsey-Hayse style direct replacement discs so I didn't have to swap spindles. I too swapped out the old lines for a pre-bent SS set, but as I originally did not have a booster, I used the drum brake set of lines. While at it, I replaced the rears as well with SS.

Just this year, I finally added the power booster,( I would definitely recommend an ORIGINAL style booster) but as you note, the position is totally different. I have a manual trans car, so I actually had to re-drill and add a new pin to the pedal as used manual pedals are practically impossible to find. At this time, I installed ball bearing pivots for the clutch pedal shaft. Mustang Steve sells a kit for this if anyone else is going this route. Now, as I had to remove the entire pedal hangar, the trick was to remove the steering column, makes life soooo much easier.

On the master cylinder, reworked lines and fittings were needed as in my case, I used a separate rear brake bias control, not a combo distribution block. The other issue I found was as my original SSBC M/C was for non power disc / drums, is a 1" bore. I believe a 15/16" is required for a power booster set-up. I find my brakes a bit sharp, but manageable. Not found a 15/16" M/C yet though. All the suppliers seem to only have 1" ones. Hmmmm!.

Assuming your car is an auto trans, makes life so much easier on a swap like this (getting parts). If anyone is going to replace the plastic pivot bushings with clutch shaft ball bearings, the bracket must be removed. With the steering column out, replace the rubber seal to the fire-wall and there is a thin metal plate with 4 bosses welded on, which will need to be drilled out for the new mount bolts. If this plate is not replaced, it will alter the position of the brake pedal bracket and column. I've read where others didn't put it back in and wondered why they had problems. Just a thought.

You probably are past this, but it may help others. Enjoy your new stopping power!!

Geoff.

 I learn something new every day!

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Good info. I did the same thing on a 71 a sports roof using a 72 Grande parts car.

 

I picked up a rebuilt booster/ MC combo off of rockauto.com for a very reasonable price similar to you....

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Good info. I did the same thing on a 71 a sports roof using a 72 Grandé parts car.

 

I picked up a rebuilt booster/ MC combo off of rockauto.com for a very reasonable price similar to you....

 

Yes, the original booster, reman or original style is the only choice in my humble opinion. I tried one of those so-called direct fit replacement "things" that was supposed to fit right where the manual M/C was located. Yeah right, not a chance on a 71-73. Long story, not going into that here, just DON'T BUY that crap!

Geoff.

 I learn something new every day!

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The picture above is the power booster I used. When I compared it to an original it was slightly different. But it bolted up just fine and works fine. The one you had trouble with, was it very different looking?

 

 

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I like the idea of SS brake lines, I had one rust out on an old pickup, luckily I was in the driveway when my foot went to the floor.

 

How did you get them to stop leaking? I'm guessing it was by tightening, loosening, and tightening until they quit.

 

 

“If you can't explain it simply, you don't understand it well enough.”

--Albert Einstein

 

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The picture above is the power booster I used. When I compared it to an original it was slightly different. But it bolted up just fine and works fine. The one you had trouble with, was it very different looking?

 

 

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Yes, I believe the new old style boosters are slightly different to the original. These are I think, 9" single diaphragm booster. The one I bought that was supposed to be correct, was a dual diaphragm type about 7 or 8" diameter. You can look this up in the NPD catalog as they still try to sell it for our cars. No way, no how!

It may fit earlier models, but still the fulcrum point will be different, too high.

Geoff.

 I learn something new every day!

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I like the idea of SS brake lines, I had one rust out on an old pickup, luckily I was in the driveway when my foot went to the floor.

 

How did you get them to stop leaking? I'm guessing it was by tightening, loosening, and tightening until they quit.

 

Yeah Don, I know what you mean about brake line failures. I've had two in my lifetime. One in a England, when I had to pitch the car sideways a slide across 3 lanes of traffic, very scary!! The other time was in my 72 Mach 1, just coming to a stop light by my house. I took to the sidewalk to avoid a head on crash, drove across the neighbor's lawn and into my drive. Again very scary split second decisions, but I didn't hit anyone or anything!! I do NOT want that experience again.

Sorry to get off topic.

Geoff.

 I learn something new every day!

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I like the idea of SS brake lines, I had one rust out on an old pickup, luckily I was in the driveway when my foot went to the floor.

 

How did you get them to stop leaking? I'm guessing it was by tightening, loosening, and tightening until they quit.

 

 

Exactly

 

 

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The picture above is the power booster I used. When I compared it to an original it was slightly different. But it bolted up just fine and works fine. The one you had trouble with, was it very different looking?

 

 

Sent from my iPad using Tapatalk

 

Yes, I believe the new old style boosters are slightly different to the original. These are I think, 9" single diaphragm booster. The one I bought that was supposed to be correct, was a dual diaphragm type about 7 or 8" diameter. You can look this up in the NPD catalog as they still try to sell it for our cars. No way, no how!

It may fit earlier models, but still the fulcrum point will be different, too high.

 

 

Did it look more like this?820f1cae9e53a56ef63f0e11834c1856.jpg

 

 

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Pastorpat,

 

Nice work there! I was fortunate to have a donor car to work from. My 1971 Sports Roof had the wonderful drums and I did the conversion dance also.

 

mustang7173

Thanks,

mustang7173 🇺🇸

"Courage is being scared to death but saddling up anyway" -- John Wayne

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The picture above is the power booster I used. When I compared it to an original it was slightly different. But it bolted up just fine and works fine. The one you had trouble with, was it very different looking?

 

 

Sent from my iPad using Tapatalk

 

Yes, I believe the new old style boosters are slightly different to the original. These are I think, 9" single diaphragm booster. The one I bought that was supposed to be correct, was a dual diaphragm type about 7 or 8" diameter. You can look this up in the NPD catalog as they still try to sell it for our cars. No way, no how!

It may fit earlier models, but still the fulcrum point will be different, too high.

 

 

Did it look more like this?820f1cae9e53a56ef63f0e11834c1856.jpg

 

 

Sent from my iPad using Tapatalk

 

Yes except it was not painted, but dichromate. I think it is the Bendix type. It is still listed on page 87 of the current NPD catalog. It actually looked more like the one on top of p86.

DO NOT EVER THINK THIS ONE WILL FIT with out modification to the firewall lip. It simply will not bolt up in the manual M/C position.

Also it is way too high and the cross brace is in the way. I have posted this with pictures before if you search. I would never, from my own experience, recommend this type of booster. It HAS to be stock or very close to it. OK enough!!

Geoff.

 I learn something new every day!

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  • 3 months later...

Pastorpat, I too have done this dance. It has been posted on before, but it seems you have a pretty good handle on it from your own experience.

The swap from drums to discs isn't that hard. In my case I went with SSBC Kelsey-Hayse style direct replacement discs so I didn't have to swap spindles. I too swapped out the old lines for a pre-bent SS set, but as I originally did not have a booster, I used the drum brake set of lines. While at it, I replaced the rears as well with SS.

Just this year, I finally added the power booster,( I would definitely recommend an ORIGINAL style booster) but as you note, the position is totally different. I have a manual trans car, so I actually had to re-drill and add a new pin to the pedal as used manual pedals are practically impossible to find. At this time, I installed ball bearing pivots for the clutch pedal shaft. Mustang Steve sells a kit for this if anyone else is going this route. Now, as I had to remove the entire pedal hangar, the trick was to remove the steering column, makes life soooo much easier.

On the master cylinder, reworked lines and fittings were needed as in my case, I used a separate rear brake bias control, not a combo distribution block. The other issue I found was as my original SSBC M/C was for non power disc / drums, is a 1" bore. I believe a 15/16" is required for a power booster set-up. I find my brakes a bit sharp, but manageable. Not found a 15/16" M/C yet though. All the suppliers seem to only have 1" ones. Hmmmm!.

Assuming your car is an auto trans, makes life so much easier on a swap like this (getting parts). If anyone is going to replace the plastic pivot bushings with clutch shaft ball bearings, the bracket must be removed. With the steering column out, replace the rubber seal to the fire-wall and there is a thin metal plate with 4 bosses welded on, which will need to be drilled out for the new mount bolts. If this plate is not replaced, it will alter the position of the brake pedal bracket and column. I've read where others didn't put it back in and wondered why they had problems. Just a thought.

You probably are past this, but it may help others. Enjoy your new stopping power!!

 

 

Mine is a manual car as well. It was a three speed but is now a 5 speed. I really did not have issues with the clutch pedal. But in the process it was a real pain to hang the power brake pedal.

 

 

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  • 3 months later...

It would be awesome if someone could link to the firewall templates to mount the new booster.

I supposed the brake pedal mount has the holes for the booster to bolt thru like every other ford.

"I drank what?" - Socrates

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jowens1126,

I bought my Manual brakes to Power conversion kit back in the spring from Leed brakes, no modification to the fire all at all, its fit right in the stock opening after removing the block off plate, they also show you how to modify the pedal for power brakes, it 2" lower then manual.

http://leedbrakes.com/ag-645546.645576.645577-1972-ford-mustang.html

 

 

20170405_183522.jpg

 

 

20170407_192608.jpg

Iyman

1972 Mustang Convertable :run_horse:  [button=http://www.7173mustangs.com/forum-garage?filterxt_uid=1507]Visit My Garage[/button]

Visit the Mustang Car Club of New England Facebook Page [button=https://www.facebook.com/MUSTANGCCNE]MCCNE FB Page[/button]

 

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  • 6 months later...

Are spindles from front drum brakes different as disc brakes?

Mustang, beer and rock'nroll

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Are spindles from front drum brakes different as disc brakes?

 

Check, but I think it depends on what brand and type of conversion kit you buy. As mentioned before, I went with the Kelsey-Hayes style 4 piston kit and this kit did NOT need to change the spindles. All that was needed was to remove the drum hub and that can be done without taking it apart first. Again, I replaced all my lines with SS, but it still only took me a little over 2 hours to do.

Geoff.

 I learn something new every day!

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Are spindles from front drum brakes different as disc brakes?

 

Check, but I think it depends on what brand and type of conversion kit you buy. As mentioned before, I went with the Kelsey-Hayes style 4 piston kit and this kit did NOT need to change the spindles. All that was needed was to remove the drum hub and that can be done without taking it apart first. Again, I replaced all my lines with SS, but it still only took me a little over 2 hours to do.

 

Actually my plan is to swap the disc brakes from my Grandé to the Mach 1 which has drums.

Both cars are from 73 wih brake boosters.

Marti reports says front disc brakes on the Grandé and same for the Mach 1. Don't know if Marti reports are 100 % trustable or could be the Mach 1 has been swapped before sent to Europe.

Mustang, beer and rock'nroll

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It would be awesome if someone could link to the firewall templates to mount the new  booster.

I supposed the brake pedal mount has the holes for the booster to bolt thru like every other ford.

 

 Ok, looks like this was never answered. I'm not sure what your question is, but I'll try. The pedal mount support needs to have the two lower holes drilled out to 3/8th" removing the old threads. Mine was different because I wanted to replace the clutch pivot bushing with ball bearings, a kit I bought from Mustang Steve. If you're doing an automatic I think it can be done without removing the bracket, just a pain to get in there to replace the pivot pin and bushings, but removing the seat helps big time. ( I do that now any time I'm working in that area)

If you're doing either a manual or automatic, the push rod pin MUST be lowered 2". Automatic brake pedals are a bit easier to find, but the manual ones are like hen's teeth. I got a new pin with my bearing kit, drilled the hole and welded in the new pin 2" lower. As a bonus, if anyone wanted to return it to manual drums (why I don't know, but!!) the original pin is still there.

Geoff.

 I learn something new every day!

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