Technical A QUESTION ON PLUMBING MASTER CYLINDER FOR DRUM BRAKES

I am hoping to get some help with this. I am currently plumbing my brakes and I am in doubt of which port goes to the front and which port goes to the back
I am at a point where I can easily correct it.

I am using a 10-1329 Cardone Master cylinder.
Currently I am using the front port, closest to the pedal, for the front brakes. The rear port, farthest away from the pedal, for the rear brakes.
I am using drums in all 4 corners.

I am told, it should be plumbed the other way around as the rear port will push fluid first; therefore, that port should go to the front.

I asked Summit Racing, since I was shopping for some other parts and they carry same M/C, and the Tech said it didn't matter because both reservoirs are the same size

Which one is right???

Primary Port Size is 9/16 X 18
Secondary Port Size is 1/2 X 20

Thank you

 

Not familiar with that actual Master Cylinder, but generally its front/front & rear/rear.

 

If the reservoirs are the same size and it’s not a stepped bore master, it makes zero difference


Sent from my iPhone using H.A.M.B.

 

There is no difference in the bore size, piston, or the hydraulic pressure the piston makes. The manufacture has intended for tandem master cylinders to use all that wad of factory looking tubing, and the brass valve. That is why the port sizes are different. to keep all that sorted out. If you don't use that crap, your pedal will go to the floor when you open a brake bleeder. I put adapters in my ports, and reduced everything back to 3/16 line, and didn't use the crap. If you turn the master cylinder around, and mount it under the floor, the normal rear port becomes the front. That's how I plumbed mine. The car stop's fine. Front port to front brakes.
On a disc brake master cylinder they want the larger fluid chamber going to the front brakes, because calipers require more fluid to operate.

 

If you have a front disc/rear drum brake system and one reservoir is larger than the other, the large one is for the front discs.

It makes no difference if it's a drum/drum system

 

Thank for the help. I am glad I asked

 

Here's a hint to help eliminate a leak source. Instead of adapters from the large nuts to your chosen steel line size, go to NAPA and buy line nuts in 9/16 and 1/2, with the proper center hole size for your line. Looks cleaner too.

 

Thank you. That's a good idea.

 

Just converted my 36 three window to 4 wheel hydraulic drums (F1 st up) with similar looking Raybetos MC with internal residual valves. However, my primary port, front brakes, is 1/2-20 thread (your blue plug) and secondary port, rear brakes , is 9/16-18 thread(your red plug). I used 1/2 and 9/16 inverted flare nuts instead of adadpters......not alot of room under the coupe between MC and frame X member,and I personally think it look better. I didn't remove the MC piston to check if there was a diameter difference but I'm assuming the engineers had a reason for specifying primary and secondary ports. MC for 68 mustang manual drum brakes. Car not yet road worthy but brakes pumped up nice with firm pedal.
If you like the final installation don't loose the receipt or P/N of the MC...just in case you ever need to replace. My Raybetos MC would fit in your vehicle but the port thread sizes are reversed from yours.
Good luck

 

Here is a catalog EVERYONE needs. Been using it for 20 years. Helps finding fittings.

https://images.carid.com/edelmann/info/catalog/2011-catalog.pdf

 

I have been doing brakes for longer than I care to remember and I always used the proper fitting with the line size that the MC was made for. I also always use the stock distribution block or combination/proportioning block in my set ups and they all have worked well. I try to duplicate what the manufacturer designed.

Pat

 

the front normally goes to the front brakes
at least it does on all mine.
the larger port is generally for the larger sized line going to the rear brakes
If building new lines, I like to purchase the correct fittings to keep from using unsightly adopters.
NAPA and autozone generally keeps these guys in stock.
a 9/16 fitting for 1/4 inch line --rear (unless the factory used 3/16)
and a 1/2 inch fitting for 3/16 inch line ---front

 

My experience tells me primary port , front brakes, secondary rear brakes. Read the instructions twice .....fit once. I found out the hard way...disc/drum, disc/disc, drum/ drum all different....