Manual drum to disc conversion

Haze08

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Just picked up my first classic car yesterday 66 Fury III. I have been searching and reading for hours and maybe I am just missing it.

I have a manual drum setup and would like to at minimum do a front disc conversion. I have a single resevoir master cylinder. From what I understand it looks like there is a different master cylinder for manual disc brakes. If I were to switch to a power setup I would need several parts including a different brake pedal.

Can I stay with a manual system and still run disc reliably? Just the front or front and rear?

Has anyone done this and how do you like it?

Thanks Kenny
 
Can I stay with a manual system and still run disc reliably? Just the front or front and rear?
Yes. The extra effort is not that bad.
Change to the proper master cylinder.
Completely rebuild the rear drum brakes.
Install proportioning valve to balance hydraulic pressure tween front and rears
K. I. S. S.

Personally, I had a 66 Fury Big Block and kept the drums.
I could still lock up all four.
It's the tires that affect your stopping distance.
 
I have a complete parts and tips article on how to do this conversion using factory parts.

Keep in mind that there was never a manual brake DISC system for C bodies - it was always a power system.

Contrary to some opinion, disc brakes are superior to drums. Tires play a role without a doubt, but beyond that, discs have better heat dissipation, fade resistance (multiple high speed highway stops), etc than drums.

To do it right, you will need to swap out your manual brake pedal assembly and firewall plate to a 65-68 power brake pedal set. Power brake pedals are different than manual brake pedals.

The disc brake assemblies (spindles/calipers etc) from 1970 - 1973 C bodies are a bolt in, and parts are still reasonably easy to find. The best version from those years is the 1973 setup. The 65'69 disc setup is not easy to service and should generally be avoided.

You will need a 65-69 C body disc booster, as the 65-68 drum brake booster is NOT adequate, even though it will bolt up. Use a 67 and up dual reservoir master cylinder.

PM me for more details.
 
Ross, why are you saying switch to a power pedal? I started my manual discs with the original power pedal and it was terrible. Much better with a manual pedal.
 
Because I am not aware of a factory engineered manual disc system, and I would not be qualified to advise anyone on how to assemble one. The factory's excellent power disc brake systems were aknowledged to be top quality, and the parts are there to do it.

No doubt - the power brake pedal would not have nearly enough leverage multiplication to operate a manual brake setup of any sort.

That being said, if soneone was intent on staying with manual brakes and assembling a disc brake setup, I expect it can be done. I just don't have the knowledge on what to suggest.

I'd be interested in your experiences and what components you chose. :)
 
I'm not perfectly happy with mine, but it is 73 discs up front, modern plastic/AL master cylinder, and the manual brake pedal. It's still a firm pedal with not a ton of travel.
The power pedal did not give me near enough leverage to stop the car without both feet stomping and I'm no shrimp. I used a Wilwood prop valve since mine was a 4 drum car.
 
I hear you. A manual system used with a power brake pedal just would be truly unsafe, as there would be nowhere near enough leverage from that pedal.

I expect you could improve your system's pedal feel with a master cylinder bore change - and while my instincts say a smaller bore would do it, I am actually not sure. This is where my experience ends, and being brakes, I am not comfortable experimenting with that sort of thing given today's traffic density. That, and the fact that the lawyers would have a field day if it was determined in the case of an accident, that the car had a piece-meal non-OEM-factory braking system installed.

Ultimately, unless one is an experienced brake person and has the time to experiment safely, I feel it prudent to go with (and therefore recommend) a tried and true factory engineered package - from power brake pedal, proper disc booster, dual res master, metering valve yadda yadda. Bolt it on, bleed it, and go (more importantly, stop!) with confidence.
 
If it wasn't for the turbo sitting right there, I'd have a booster yes :thumbsup:

I did move to the 15/16th bore or whatever, it didn't make a lot of difference.
 
Just picked up my first classic car yesterday 66 Fury III. I have been searching and reading for hours and maybe I am just missing it.

I have a manual drum setup and would like to at minimum do a front disc conversion. I have a single resevoir master cylinder. From what I understand it looks like there is a different master cylinder for manual disc brakes. If I were to switch to a power setup I would need several parts including a different brake pedal.

Can I stay with a manual system and still run disc reliably? Just the front or front and rear?

Has anyone done this and how do you like it?

Thanks Kenny
I’ve been beat up here before about this but I’ll still say it again because it’s true. Going to circa 1966 power disc is not a magic bullet. If you’re going to go to all the trouble to switch over then go with modern parts. Unless you’re doing a 100% OEM resto then what I’m saying is of no help for that path. There are tons of kits out there - see Mopar Action Magazine for all of Mr Ehrenberg’s great tech on a his subject. Why put all the blood sweat n years into swapping over to get old fashioned performance. That’s why I’ve stuck w power drums. I know disc are better than drum but old fashioned parts not so much so. Any new car can out brake a stock disc brake classic car. Classic parts won’t perform like a new car - even a Kia/Hyundai is better. Sad but true...
 
yes, and the scarebird kits and some others are junk and have no right being sold - I agree with Ross on some of that sentiment. I'd rather have the OEM setup than many of the kits on the market.
And there are some excellent kits out there as well.
 
I have scarebird. That junk uses Ram 1500 calipers and thick 11" Galaxy 500 rotors. Stops well. But I've never had OEM to compare to and likely OEM would outlast my kit. I'll let the next 2 owners worry about that.
 
I have scarebird. That junk uses Ram 1500 calipers and thick 11" Galaxy 500 rotors. Stops well. But I've never had OEM to compare to and likely OEM would outlast my kit. I'll let the next 2 owners worry about that.

BNZ84: Did you replace the stock brake master cylinder on your Scarebird kit? I just completed the same modification on my 1969 Fury II. I either cannot bleed brakes correctly or I need to upgrade the master cylinder to something with a bigger reservoir for the front disc brakes.
 
BNZ84: Did you replace the stock brake master cylinder on your Scarebird kit? I just completed the same modification on my 1969 Fury II. I either cannot bleed brakes correctly or I need to upgrade the master cylinder to something with a bigger reservoir for the front disc brakes.
Yes, I had power drums all the way around so my master was also drum/drum and I replaced it with disc/drum master.
 
Yes, I had power drums all the way around so my master was also drum/drum and I replaced it with disc/drum master.
Did you use a power disc/drum master cylinder for a Fury or another MOPAR?
 
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Use a 67 and up dual reservoir master cylinder.
To clarify - make sure it's a disc booster to get the larger reservoir size.

Ross, why are you saying switch to a power pedal? I started my manual discs with the original power pedal and it was terrible. Much better with a manual pedal.
And if you mix MB pedals with a power booster you'll get a super-mushy feel. DAMHIK. Good braking, though!

Because I am not aware of a factory engineered manual disc system, and I would not be qualified to advise anyone on how to assemble one. The factory's excellent power disc brake systems were aknowledged to be top quality, and the parts are there to do it.

That being said, if soneone was intent on staying with manual brakes and assembling a disc brake setup, I expect it can be done. I just don't have the knowledge on what to suggest.

I'd be interested in your experiences and what components you chose. :)

I converted my sigpic car to manual discs, it was originally manual drums. I discovered there was a 1/2-ton Dodge truck application of the mid-70s with MDisc, so I used that mast cyl and a modern combination valve from Fine Lines or somebody similar, and braided brake hoses (love them, they do add noticeable response to the brake pedal based on another car I swapped them onto). It has the same feel as manual drums, but with all the confidence of discs. I can stop normally with 1 leg, and I'm not a superman. I've done a few hard 2-leg 30-0 stops and it'll stretch your eyeballs and you'll need to reach for the dash - all with no fuss or fanfare or wheel lockup (but I have kinda-wide tires).


Any new car can out brake a stock disc brake classic car. Classic parts won’t perform like a new car - even a Kia/Hyundai is better. Sad but true...
I disagree with 'any'. I've driven a number of newer rental cars in the last few years, and although I've done no scientific testing of their braking, I'd put my 68 up against any modern plain SUV or plain commuter car. Some might do better, but I believe some will do worse. You could argue about 'stock' regarding my tires and brake hoses, I suppose, but I'm using factory MC, calipers, rotors.
 
I disagree with 'any'. I've driven a number of newer rental cars in the last few years, and although I've done no scientific testing of their braking, I'd put my 68 up against any modern plain SUV or plain commuter car. Some might do better, but I believe some will do worse. You could argue about 'stock' regarding my tires and brake hoses, I suppose, but I'm using factory MC, calipers, rotors.[/QUOTE]

I think you’re missing my point.

Look like I said I’m not trying to pick a fight I’m just saying don’t get a false sense of security by adding old school disc brakes and seeing the great improvement as a silver bullet. A new Demon could almost drive to the track in 1969 and beat Ronnie Sox and then drive home. A new Shelby mustang (if it doesn’t spin off into the crowd) could probably compete and win in the 1969 trans am series, time marches on.

I almost hit a kid in our neighborhood a while back. His little dumb life was spared by power drum brakes, the speed limit and me paying attention. Another member here almost hit a bear. He was saved by manual drums, a loud horn and him again paying attention. Most drivers today don’t pay attention and take crazy chances because the cars handle and brake so well. My 80’s drivers ed class was crazy about following distance because we all drove cars with drum brakes from time to time. Tailgating used to be a crime now it goes unnoticed.

I bet these were all disc brake cars.

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Stuff like this guy below is a big reason it’s so dangerous to assume just by adding discs you’re good. Nothing can defeat the power of stupidity. Have fun and enjoy your cool car and careful out there bud.

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