Master Cylinder which port is which

[Southtowns27]

I'm putting a '69 Mustang drum/drum master cylinder in my '46 pickup. Does it matter which port goes to the front or rear since both reservoirs are the same size?

 

[KULTULZ]

Actually no, but I would put the front brakes on the front port.

What is important is if the CHI-COM SLOPPY COPY included RESIDUAL PRESSURE VALVES in each outlet port which are needed for drum brakes. Most aftermarket do not.

Is the MC installed above or below the wheel cylinders level?

 

[Gene F]

The rear port always runs the front brakes. Go figure... It has to do with the way the piston works in the master cylinder I guess.

 

[Alaska Jim]

most times , if the car has front disc brakes, and rear drums, the larger reservoir goes to the front

 

[KULTULZ]

The rear port always runs the front brakes.

Not always. Differing time periods brake design and how the vehicle is valved (pre-ABS).