Brake Line Distribution block port sizes are different

-
philip's66

philip's66

You may all go to Hell, and I will go to Texas.
Joined
Feb 11, 2011
Messages
191
Reaction score
213
Location
Houston,Texas
I am converting my 66 Dart to dual master cylinder & noticed that 1 port on the distribution block appears smaller than the other 2. Am I correct in assuming this would be the correct port to block off and use the other 2 for the front brake cylinders to insure the same amount of brake fluid goes to both cylinders?
What was the reasoning behind this difference ?more pressure to the rear?
 
No. All Mopar brake tubes are 3/16 OD and the "standard nuts" for that size are on the ones you buy at the parts store. But especially with the dual master, Ma started using NON standard nuts on the tubing up there in front, for the master / distro /prop/ metering valve so the assembly folks could "only" put it all together one way.

On a single system, the distro block is just that......basically a tee. So if one nut is different, you could buy a plug (inverted flare plug) and plug that one off. They are "called out" (sized) by the brake line size they are supposed to fit "standard"

440269-131280.jpg


Here's some specs, see page D14

http://www.stanleymotorcarriage.com/Parts/images/ParkerFittings.pdf

flare.jpg
 
My 74 Cuda...
Dual MC
Front reservoir 1/2" fitting
Rear reservoir 7/16" fitting.
3/16 tubing on both.
 
Dfr360cuda said:
My 74 Cuda...
Dual MC
Front reservoir 1/2" fitting
Rear reservoir 7/16" fitting.
3/16 tubing on both.
Click to expand...

You have to be even more careful when dealing with "the others" (GM, Ford, etc) Some of those nuts over the years, are not even standard inverted flare. Some of them are the same ID but with different threads (pitch, or TPI)

"Back in the days" when we ran hydraulic operated trailer controllers, you could buy different tees and bushings to deal with these fittings.

s-l300.jpg
 
I don't understand why you are blocking off anything. If you have a dual master, it has two ports out. Each goes to one of the "in" ports on the distribution block (and they are specific -- one is for the front brakes, the other for the rear). That leaves 3 "out" ports: one for each front line, and one for the rear brakes. So what are you blocking off?

Are you trying to use the single master cylinder distribution block? I don't see how that will work. You need a dual circuit distribution block to match the master cylinder.
 
mvh said:
I don't understand why you are blocking off anything. If you have a dual master, it has two ports out. Each goes to one of the "in" ports on the distribution block (and they are specific -- one is for the front brakes, the other for the rear). That leaves 3 "out" ports: one for each front line, and one for the rear brakes. So what are you blocking off?

Are you trying to use the single master cylinder distribution block? I don't see how that will work. You need a dual circuit distribution block to match the master cylinder.
Click to expand...



No he's converting a single system to dual. What the OP is talking about is common practice. The single distro block comes "in" from the master, then out to the front and rear brakes. You have to separate the circuits.
 
I may not have explained myself correctly. My concern is with the original distribution block- where the brake lines branch to the left & right front wheel cylinders & then to the rear tee- not the master cylinder. 1 port on the distribution block appears smaller than the other 2.I also noticed on the rear Tee that those ports for the inverted flares were the same size as the 1 different flare inlet/ outlet/ port /hole size.
 
if your going from a single pot master to a two pot master you need to change the distribution block to a two pot type.
You have 2 fluid out lines from the new master so you need 2 fluid in lines to the distribution block, one for each circuit, 1 front and 1 rear. No blocking of any ports should be required.
 
philip's66 said:
I may not have explained myself correctly. My concern is with the original distribution block- where the brake lines branch to the left & right front wheel cylinders & then to the rear tee- not the master cylinder. 1 port on the distribution block appears smaller than the other 2.I also noticed on the rear Tee that those ports for the inverted flares were the same size as the 1 different flare inlet/ outlet/ port /hole size.
Click to expand...
Basically, on a "stock" setup all the threads on the fittings that go to the rear brakes are larger than the threads on the fittings that go to the front brakes. All the lines are 3/16" though.
 
Thanks for your replies.
On Valiant .org& Slant Six.org there is pretty detailed info on how to convert to dual with the original distribution block -even says to check for restrictions. 1 line to the front distribution block,plug the rear port & run 1 line from front pot of master cylinder directly to the rear. When I finish this I will update with any issues or problems i came across . I did purchase a new rear tee fitting & those inlet ports are MUCH larger than the ones on my original- not sure why .
 
69_340_GTS said:
Basically, on a "stock" setup all the threads on the fittings that go to the rear brakes are larger than the threads on the fittings that go to the front brakes. All the lines are 3/16" though.
Click to expand...
It's not the threads that I am asking about it is the diameter of the holes in the distribution block- they are different diameters. Just trying to wrap my brain around that.
 
So....back to the original question. Any idea the inside diameter of 1 port would be a different size than the other 2 - both sides of the rear t is also the same i.d . as the 1 odd ball on the front distribution valve.Really small nearest I come to with calipers is 1/16" others are 1/8". Could this be to insure the brake cylinders would work correctly?Fluid distribution ? I am pretty sure Mopar engineered it this way for a reason- does anyone have an answer?
 
philip's66 said:
So....back to the original question. Any idea the inside diameter of 1 port would be a different size than the other 2 - both sides of the rear t is also the same i.d . as the 1 odd ball on the front distribution valve.Really small nearest I come to with calipers is 1/16" others are 1/8". Could this be to insure the brake cylinders would work correctly?Fluid distribution ? I am pretty sure Mopar engineered it this way for a reason- does anyone have an answer?
Click to expand...
To get more fluid to the front, a built in bias valve.
 
You must log in or register to reply here.
-

Back
Top