Thinking of converting to Manual Brakes

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straightlinespeed

straightlinespeed

Sometimes I pretend to be normal
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I have a 71 Scamp, with power brakes and Im thinking of converting over to manual brakes. Has anyone ever done this? What all is needed? Can I keep the stock proportioning valve?

By the looks of it the stock reservoir should bolt into place but not sure about the way the brake pedal would work out along with the push rod and such.

Im wanting to clean up the engine bay and make the car lighter for racing. Thanks ahead of time for the help
 
i removed the stock booster and master cylinder and but a newer model mopar master cylinder on a 73 Duster....

brakes work just fine.
 
Back in the day, about 1978 or so, my step father added power brakes to my B-body dodge. As I remember he had to change the push rod and add the booster. My guess is that going the other direction would be pretty much the same thing.
 
straightlinespeed said:
Ok, I'll check to see if I can find one tomorrow. Not sure if the auto parts stores have one otherwise I will be going to the want adds.
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Read that I should probably swap to a manual Master Cylinder also because it has a bigger piston and wouldnt have such a hard pedal feel. Problem is Im not sure what MC would work with my car. I have front disc and rear drums. Also does anyone have a manual push rod they could part with?
 
Try your current MC. You probably don't want a bigger piston bore with disc brakes, since that would make the pedal harder to push. Kind of confused by what you say, because I recall that power brake MC's had a SMALLER bore. That sounds counter-intuitive until you consider the lever arrangement in the booster. I expect that most/all factory disc cars came with power brakes, so you are going off-book. If you change the MC, consider a modern aluminum MC w/ 2 bolts to save weight. A 1" D or smaller bore sounds right.
 
straightlinespeed said:
Read that I should probably swap to a manual Master Cylinder also because it has a bigger piston and wouldnt have such a hard pedal feel. Problem is Im not sure what MC would work with my car. I have front disc and rear drums. Also does anyone have a manual push rod they could part with?
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Get yourself a "New" 1973 Dart manual disc M/C. If your going to put just 1 new part on your car,a new M/C should be the part.Stopping is good.Use your old M/C as the core.Rock Auto would be my first choice. But Napa,Oreillys,Autozone,ect will work.

If weight is an issue,go with the aluminum late model M/C. You will also need the 4 to 2 bolt adapter.
 
Make sure you get a disc/drum master.
The disc master is the one with a large pod and a small pod.
The one with the same size pods is for a drum/drum car.

Side note: The small black rubber grommet is essential. Install it in the M/C.
This holds the brake rod in,when assembled. It should come with the master.
 

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Johnny Dart said:
Make sure you get a disc/drum master.
The disc master is the one with a large pod and a small pod.
The one with the same size pods is for a drum/drum car.
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Good info to know! The prices are not to bad on them! Im actually suprised plus I have a discount code to use with Rockauto!
 
BillGrissom said:
Try your current MC. You probably don't want a bigger piston bore with disc brakes, since that would make the pedal harder to push. Kind of confused by what you say, because I recall that power brake MC's had a SMALLER bore. That sounds counter-intuitive until you consider the lever arrangement in the booster.
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A larger bore master cylinder will increase the leg effort needed to stop the car. What you want is a 15/16" master cylinder so you won't need two legs to get the car to stop. Order one for a '73 Dart with power brakes. If your car already has the 15/16" bore master cylinder and its in good shape then you are all set. The push rod hole is the same as a manual brake car.

Mopar typically put the larger bore master cylinders on the manual brake cars and smaller bore units on the power brake cars. Should have been the other way around.
 
Ok, now Im confused, do I want to order a manual or power MC. I have heard the 15/16" bore thing before so I get that part.

Does anyone know what size bore a 71 Scamp has for its MC? I would check but the car is 3 hours away from me.
 
Now your over thinking it.Its not that complicated.
Grab a 73 master,and bolt it in. Manual or Power,will work.
The difference in the 2 will be minimal.
 
straightlinespeed said:
Read that I should probably swap to a manual Master Cylinder also because it has a bigger piston and wouldnt have such a hard pedal feel. Problem is Im not sure what MC would work with my car. I have front disc and rear drums. Also does anyone have a manual push rod they could part with?
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No, the bigger piston will create a harder pedal. Mopar put the "soft" pedal small piston MC on the power brake cars -- who knows why? Most people seem to like the small piston converted to manual. I can vouch that the factory manual disks require serious pedal effort.

All the disk brake MCs are interchangeable -- A, B, E -- you just want to look at the bore sizes.
 
I used one for a 1987 Dodge Ram. Stops effortless with LBP 73 disc assembly
 

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straightlinespeed said:
Ok, now Im confused, do I want to order a manual or power MC. I have heard the 15/16" bore thing before so I get that part.

Does anyone know what size bore a 71 Scamp has for its MC? I would check but the car is 3 hours away from me.
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Order for a '73 with power disc brakes.
 
Thank you guys for all the help I ordered one up! It will be awhile before I get the car back on the road to let you all know how it stops. I appreciate all of your help. This site is great!
 
On my C body, plus B & E bodies (I think), the booster mounts directly to the firewall. That is typical of most cars. In all Mopar A-bodies I have seen, the booster mounts on brackets that stand it away from the firewall, and more importantly higher than the pedal rod so that it clears the driver's valve cover in a small block. The later might not be a problem in a slant, but I think they used the same brackets. At least I recall I got the booster setup in my Dart off a 74 Dart slant. In between the pedal rod and booster rod is a lever. The lever greatly reduces the force applied to the booster, hence they used a smaller bore MC on power brake cars. GM A-bodies don't use a lever. Instead they angle the booster upward and use a different hole on the brake pedal for power brakes.
 
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