With the master cylinder shown upgrading from a single port to this double which would be the front brakes and which the rear? I have the required check valves and need to know which goes to where or does it matter.
The back reservoir has a larger output fitting so that was my guess. Line is not bigger, 5/16th line but takes a larger fitting.
The rear port goes to the front, because it puts pressure to the front brakes first then the rear, the way the internals of the master is designed,
The rearmost port goes to the front brakes. That master looks like a drum/drum unit. Usually the rear reservoir on a disc/drum cylinder will be larger because of the fluid capacity of the calipers.
^Yep Johnny Gee is right GM is Front to Front. Plumbing my Model A as we speak using the early Ford manual drum drum dual pot. On the Ford 67-73 M/C the rear reservoir goes to the front. If you lose hydraulic pressure in the rear circuit the volume of fluid between the primary and secondary pistons is lost. the spring between them collapses, and the rear piston mechanically pushes the front piston maintaining pressure in the front circuit. If you lose hydraulic pressure in the front circuit the rear circuit will maintain pressure. Damn Fords! Edited for clarity.
Looks good. I guess I will never understand why AN fittings are not DOT approved. Most everyone knows they are used extensively in race cars and aircraft.
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