Power to manual brakes

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GSXcite

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I want to remove the power brakes on my 66 barracuda. It has drum brakes front and rear.
I'm looking at Dr. Differential site at the
* aluminum master cyl. Kit with adapter
* adjustable master cyl. Push rod
* proportioning valve

Will this be what I need to make the conversation from power to manual?
Will the adjustable push rod work on the power brake pedal, or is the pedal on a manual and a power different?

Thanks for any help!
 
Very few if any drum systems need a prop valve. Are you keeping drums or converting to front disk?

My car (when it was together) had 4x disc brakes, 73/74 Duster/ Demon in front and Linc. Versailles at rear

So far as master you need a different length pushrod and usually a smaller master which gives you more leverage but requires more pedal MOVEment

Dr Diff gets great press on here, I have not dealt with them
 
I want to remove the power brakes on my 66 barracuda. It has drum brakes front and rear.
I'm looking at Dr. Differential site at the
* aluminum master cyl. Kit with adapter
* adjustable master cyl. Push rod
* proportioning valve

Will this be what I need to make the conversation from power to manual?
Will the adjustable push rod work on the power brake pedal, or is the pedal on a manual and a power different?

Thanks for any help!

You’ve got it, the master cylinder and an adjustable brake rod should be all you need unless you’re also changing over to disk fronts. Alternatively you could just buy a manual brake rod, but used originals are frequently mislabeled (ask me how I know) so the adjustable takes care of that.

If you’re changing over to front disks as well then you’ll need the new proportioning valve too. Depending on your application you may want an adjustable prop valve. It depends on your brake choices and other upgrades to the car. Factory brakes should be fine with the appropriate factory prop valve. I use the factory disk/drum valve on my cars with factory brakes, I have an adjustable on my Duster but it uses DoctorDiff’s 13” front disk kit and his 11.7” rear disk kit so I wanted to be able to tune the front/rear bias.

Why would you want to lose the power brakes

That’s easy, the stock power brakes have a soft, vague pedal feel. And the booster takes up a bunch of space under the hood, which is even more important on an early A. That’s before we even talk about how much vacuum his engine is making.

I swap all my power brake mopars over to manual brakes. I use DoctorDiff’s 15/16” bore master cylinder. It gives a heavier pedal than the power brakes, but the pedal effort really isn’t that bad at all. It’s still an easier pedal than the factory manual brakes. And it significantly improves the sensitivity and feel of the brakes, you can be a lot more accurate with your braking.
 
Why would you want to lose the power brakes
I have been unable to get the power brakes working correctly. I have sent the booster to booster Dewey twice for a rebuild, but the brakes drag, low pedal and the rebuilt cast iron master cyl. Leaks. It is my last resort to get decent brakes on the car. I would prefer to keep it all stock since the car is an unrestored 33,000 mile car, but I have been fighting this brake issue for a long time, and have tried everything I can think of to make the power brakes work, with no luck. I do prefer the feel of manual over power brakes though.
 
You’ve got it, the master cylinder and an adjustable brake rod should be all you need unless you’re also changing over to disk fronts. Alternatively you could just buy a manual brake rod, but used originals are frequently mislabeled (ask me how I know) so the adjustable takes care of that.

If you’re changing over to front disks as well then you’ll need the new proportioning valve too. Depending on your application you may want an adjustable prop valve. It depends on your brake choices and other upgrades to the car. Factory brakes should be fine with the appropriate factory prop valve. I use the factory disk/drum valve on my cars with factory brakes, I have an adjustable on my Duster but it uses DoctorDiff’s 13” front disk kit and his 11.7” rear disk kit so I wanted to be able to tune the front/rear bias.



That’s easy, the stock power brakes have a soft, vague pedal feel. And the booster takes up a bunch of space under the hood, which is even more important on an early A. That’s before we even talk about how much vacuum his engine is making.

I swap all my power brake mopars over to manual brakes. I use DoctorDiff’s 15/16” bore master cylinder. It gives a heavier pedal than the power brakes, but the pedal effort really isn’t that bad at all. It’s still an easier pedal than the factory manual brakes. And it significantly improves the sensitivity and feel of the brakes, you can be a lot more accurate with your braking.
I'M leaving the drums front and rear. So if I don't need a proportioning valve, I will need a new fitting to route the new dual master cyl. Brake lines to the existing lines to the front and rear brakes. What do you use for that? Thanks for the reply!
 
I'M leaving the drums front and rear. So if I don't need a proportioning valve, I will need a new fitting to route the new dual master cyl. Brake lines to the existing lines to the front and rear brakes. What do you use for that? Thanks for the reply!

Yup, that’s correct. No need for the prop valve if you’re keeping the brakes the same. The new master cylinder will have different sized ports though.

You can go to Napa and get some threaded adaptors for the brake line fittings if the line routing will still work. Your other option would be to make a new set of lines. Most Napa’s also have those generic brake lines that are available with different sized fittings and are bendable by hand. The green finish would give them away as aftermarket though.
 
Very few if any drum systems need a prop valve. Are you keeping drums or converting to front disk?

My car (when it was together) had 4x disc brakes, 73/74 Duster/ Demon in front and Linc. Versailles at rear

So far as master you need a different length pushrod and usually a smaller master which gives you more leverage but requires more pedal MOVEment

Dr Diff gets great press on here, I have not dealt with them
Keeping the drums. Do you know if the brake pedal itself is the same for power and manual brakes?
 
There is different ways. If you don't think you NEED a warning switch, and I don't, I would just unscrew the rear line from the current distro block. Buy an inverted flare plug and plug the distro block. Then just get a coupler / union (3/16 inverted flare to 3/16 inverted flare) and a length of "universal" brake tube. It will have the proper nut on one end. You will have to do one of two things at the master end, and likely for both fittings (Or maybe Dr Diff comes with them?)

Either scare up the proprietary nuts that fit the new master, and re-flare the tube, or find an adapter for each master cylinder fitting which are different from each other

And remember.......the rear master port feeds the FRONT brakes
 
There is different ways. If you don't think you NEED a warning switch, and I don't, I would just unscrew the rear line from the current distro block. Buy an inverted flare plug and plug the distro block. Then just get a coupler / union (3/16 inverted flare to 3/16 inverted flare) and a length of "universal" brake tube. It will have the proper nut on one end. You will have to do one of two things at the master end, and likely for both fittings (Or maybe Dr Diff comes with them?)

Either scare up the proprietary nuts that fit the new master, and re-flare the tube, or find an adapter for each master cylinder fitting which are different from each other

And remember.......the rear master port feeds the FRONT brakes
Thank you!
 
Keeping the drums. Do you know if the brake pedal itself is the same for power and manual brakes?

Pretty sure the pedals are the same. I’m not an early A guy though. 67-76 they’re definitely the same.
 
Yup, that’s correct. No need for the prop valve if you’re keeping the brakes the same. The new master cylinder will have different sized ports though.

You can go to Napa and get some threaded adaptors for the brake line fittings if the line routing will still work. Your other option would be to make a new set of lines. Most Napa’s also have those generic brake lines that are available with different sized fittings and are bendable by hand. The green finish would give them away as aftermarket though.
Thanks! Great info.
 
Keeping the drums. Do you know if the brake pedal itself is the same for power and manual brakes?
Yes, same pedal. If you're looking to keep it stock in appearance, just get a new master cylinder for manual brakes, and the correct push rod. Done. If you're doing a conversion, then you have lots of other options as already mentioned.
 
FEDHILL has the fittings if you can't find them local.. the easy way is hit a U-PULL yard and get the fittings off a donor car. get enough line with them to make a set of bench bleeder tubes, to bleed the new master, before you hook up the lines
 
Yes, same pedal. If you're looking to keep it stock in appearance, just get a new master cylinder for manual brakes, and the correct push rod. Done. If you're doing a conversion, then you have lots of other options as already mentioned.
Thank you for the reply. Would like to keep the stock look but want a dual Master cylinder for the safety aspect.
IMAG0024.jpg
 
FEDHILL has the fittings if you can't find them local.. the easy way is hit a U-PULL yard and get the fittings off a donor car. get enough line with them to make a set of bench bleeder tubes, to bleed the new master, before you hook up the lines
Thanks, good info.
 
Got the master cylinder, adaptor and adjustable rod from Dr. Differential. Also ordered the brake lines and distribution block from inline tube. The brake lines were not long enough to reach the factory distribution block, so I extended them. The distribution block inline tube sent would not work, so I followed 67Dart273 advice and plugged the rear brake line at the block, and went direct to the master cylinder. Walla, I have good brakes finally! Thanks for all the help guys, I really appreciate it.
IMAG0600.jpg
IMAG0600.jpg


IMAG0601.jpg
 
Voila.
Walla makes no sense. :D
4 wheel drum systems rely on wheel cylinder sizing to determine proportioning. Front disc, rear drum systems need a proportioning valve to reduce pressure to the rear to reduce the risk of lock up.
4 wheel drum cars still often have a "distribution block" where the master cylinder lines attach.
I've read in Mopar Action several times where Rick Ehrenberg berates people writing in asking about brakes. They incorrectly refer to the distribution block as a prop valve and instead of explaining the difference, he just states that the 4 wheel drum cars don't have proportioning valves. They may go away pissed or confused because the block that has 5 lines going to it HAS to be called something. He is smart but does come across as a prick sometimes.
Some GM cars had brake pedals that had 2 holes in them for the push rod that presses into the master cylinder. Top hole for manual brakes, bottom hole for power. The higher/closer the hole is to the point at which it pivots, the higher the pedal ratio. With the Mopars, there is some type of bellcrank linkage to reduce the pedal ratio. Power brakes have LESS leverage designed into them since the booster aids in the stopping action.
You can gain better pedal leverage by drilling a hole above the stock location. I did this in my '70 Charger and it made a noticeable difference.
 
Voila.
Walla makes no sense. :D
4 wheel drum systems rely on wheel cylinder sizing to determine proportioning. Front disc, rear drum systems need a proportioning valve to reduce pressure to the rear to reduce the risk of lock up.
4 wheel drum cars still often have a "distribution block" where the master cylinder lines attach.
I've read in Mopar Action several times where Rick Ehrenberg berates people writing in asking about brakes. They incorrectly refer to the distribution block as a prop valve and instead of explaining the difference, he just states that the 4 wheel drum cars don't have proportioning valves. They may go away pissed or confused because the block that has 5 lines going to it HAS to be called something. He is smart but does come across as a prick sometimes.
Some GM cars had brake pedals that had 2 holes in them for the push rod that presses into the master cylinder. Top hole for manual brakes, bottom hole for power. The higher/closer the hole is to the point at which it pivots, the higher the pedal ratio. With the Mopars, there is some type of bellcrank linkage to reduce the pedal ratio. Power brakes have LESS leverage designed into them since the booster aids in the stopping action.
You can gain better pedal leverage by drilling a hole above the stock location. I did this in my '70 Charger and it made a noticeable difference.
No way to move the hole higher on my pedal.very satisfied with the brakes now.
 
I want to remove the power brakes on my 66 barracuda. It has drum brakes front and rear.
I'm looking at Dr. Differential site at the
* aluminum master cyl. Kit with adapter
* adjustable master cyl. Push rod
* proportioning valve

Will this be what I need to make the conversation from power to manual?
Will the adjustable push rod work on the power brake pedal, or is the pedal on a manual and a power different?

Thanks for any help!
I want to remove the power brakes on my 66 barracuda. It has drum brakes front and rear.
I'm looking at Dr. Differential site at the
* aluminum master cyl. Kit with adapter
* adjustable master cyl. Push rod
* proportioning valve

Will this be what I need to make the conversation from power to manual?
Will the adjustable push rod work on the power brake pedal, or is the pedal on a manual and a power different?

Thanks for any help!
 
Hello GSX!!

My second post, I hope you are a patient man!!! I’ve got a 66 Dart GT with the same redundant vacuum chamber, you have the only other one in existence, I swear!!! I thought it was a plant from a 61 Dart/Desoto, that’s as close as I could find. I’ve got a manual master, and a summit “conversion” power unit and master sitting on the bench, and I’m torn, 50/50. I am starting to lean towards no power, clean things up, hate that extra vacuum tank. Why? Should a very mild 360 make adequate vacuum without it? Was a factory 273 4v low on vac.? Have you seen many of these beasts on your journey? Going to send now, maybe I’ve said too much!!! It kicked me out, but I found it again!! Thanks for listening GSX!!!
 
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