On a 69 Chevelle with front disc and rear drum brakes. Which line does the proportioning valve go in? Front or rear?

Both lines screw into the P/Valve. The rear brake line goes into the firewall end of the P/Valve. The front brake line goes into the front of the P/Valve which goes to a Tee fitting that splits the L&R front brake line.

On a factory 69 system there is no proportioning valve, just a metering valve plumbed into the front brakes. It hangs off to the side and under the master cylinder. From there the lines run down to a distibution block on the frame and out of the block to the front wheels. The rear line runs out of the master and directly to the distribution block, then the line out of the rear of the block runs to the rear of the car. There was no one piece "combination" proportioning valve used until 1971, 67-70 used the two piece system.

drptop70ss with the metering valve there is an in and an out which goes to the front brakes threw the distrabution block. I have this metering valve. But not installed. What does the metering valve do? The reason I ask is. I changed front disc brakes with Aerospace (disc)componets. Went from power disc master cylinder to manual master that came with front brake system. Rear drum. ( needed room for valve cover ). My line lock will not hold pressure to the front brakes when on. The wire to distrabution block activates the warning lite with brake pedal depressed, but when released it goes off and brakes are released, with line loc engaged. Will the metering valve change the pressure from front to rear.

On the factory setup the metering valve delays the front brake action to have the front disks and rear drums all actuate at the same time so the car stops evenly. Leaving it out shouldnt affect your linelock action, it sounds like your linelock isnt working..possible bad solenoid, internal hydraulic leak, or its wired and/or plumbed wrong. Try posting a line lock question in the performance section, maybe you can compare your setup to one of the other members' install.

Ok on the metering valve. On the line loc. I am pretty sure that when I got the car. The line loc had the line from the metering valve plumbed into the out side and the in side went to the distrabution block on the frame. Maybe I should plumb it backwards.. It might be a factory mistake on the in and out labeling. Do not know the brand. It is blue and maybe 2.5"x 2"x3/4 "
Is it possiable for pressure to be leaking threw the distrabution block into the rear brake line?
Thanks..... Dave

I believe the line lock is bascially an electrically actuated check valve, so if it were installed backwards it would not work. Also if the internal seals are leaking it would not hold line pressure and the fluid would leak back into the system. Again, I would compare notes with the performance forum guys. Possibly someone has the same unit as you and can tell you which port is the inlet and outlet.