Brakes

[whitesatinmopar]

My Dart has already had the 10" to 11" rear drum conversion with the 8 3/4 rear end change over, it also had front disc conversion : however it still has the original stock brake proportioning valve. What part # or model do I need to get to make the system complete, also should I or do I need to change the master cylinder? It appears to be original as well, has a slight leak but I suspect that to be only a gasket problem.     Thanks to any and all answers.

Jim

[Chryco Psycho]

I use the adjustable Wilwood proportioning valve to balance the system

[Changin Gears]

I use the adjustable Wilwood proportioning valve to balance the system

Goes in the rear brake line.

[dodj]

A little off topic, but awesome pic 'changin gears' 

[Moparal]

I'd put 10 inch drums back on the rear with front disc brakes.  And also it is less rotational weight and does make a difference

[ShelbyDogg]

do I need to change the master cylinder? Jim

Jim,  Change your master cylinder to a disk type (one bigger side) and just make sure that the larger side goes to the front disks by moving the lines to the valve, depending on if the one you use has the bigger one on the front or rear. (both are out there)  Make sure you get that valve or else your rears will lock up.

[whitesatinmopar]

Thanks gentlemen, I beleive you have sent me down the correct path. Al I certaily trust your thoughts but in my meager knowledge I don't understand honestly what your mean.      

[Moparal]

The lighter the rotational mass you have. it will take less hp to spin it.  Like 10 inch drums, lighter aluminum drums in a transmission, lighter crank , rods, pistons, titanium valves,..... Anything your engines is responsible for spinning over. The lighter it is, the quicker you achieve maximum rpm.

[ShelbyDogg]

I don't understand honestly what your mean.      

Get a master cylinder for a 72 Cuda. Hook it up. When you bleed the FRONT brakes, make sure that it is the larger of the 2 resevoirs that is going down. If not, switch the 2 lines at the junction block or MC.

[whitesatinmopar]

Rob  I understood your explanation perfectly. I was referring to Al's comments on 10" vs 11" rear drum brakes.  Thanks Al for the feed back, now that makes sense but I don't beleive I'll need to worry about that considering the Dart will be strictly a street car. And especially until I change or rebuild the rear end, it is a 8 3/4 but an open spool at the moment. That probably will be at the bottom of the priority list as far as upgrades go, but as always will be keeping my eyes open. A friend of mine said money wise I just be better off putting another (sure grip) rear end under the car as opposed to making this one into a sure grip. All I know there sure isn't much room for some meats in those fender wells anyway, I have a couple ideas as to how to squeese out another inch or so, one being modifing the spring hangers and using an off set.   

Thanks again guys.    

[Chryco Psycho]

if you are not using power brakes I use the 74 dart MC for non-power disc brakes

[whitesatinmopar]

  Thanks CP, that is the set up. I still wonder why in a small car  they optioned them with power steering but yet put manual brakes on it ?

[quapman]

Who knows WHY they did these things back when, but if you have manual brakes and your car stalls, you still have full braking function. When you lose the vacuum on a power setup, you'll need both feet to stop the car. 

Some folks use the Chevy prop valve for disc/drum. Sometimes you find em on fleebay cheap.

[Strawdawg]

if you are not using power brakes I use the 74 dart MC for non-power disc brakes

Strangely, (to me anyway) that listing shows a 1 1/32" unit for the manual brakes and a 15/16" for the power brakes.

Normally, I thought most used a smaller diameter master cylinder for the manual brakes in order to get more hydraulic pressure from less pedal pressure.   

[cudazappa]

Depends on several variables...

Size of pistons in your calipers / wheel cylinders...

how much pedal effort vs pedal travel you want...

its generally between those two sizes for manual discs.  I know AutoXcuda runs the 1 1/32" unit and likes the feel.  That 3/32" difference in bore makes a big difference!