Team13Racing

Looking to install a line lock on my 72 cutlass. Ive upgraded the front brakes to disc and replaced my master cylinder and booster with and 8" Dual diaphragm and proper disc drum MC, as well as a prop valve.
This is the line lock I want to install. Im a little confused on proper plumbing. Do I still use the frame mounted distribution block and just do some capping? This is the MC BB combo ssPageName=STRK:MEWNX:IT&_trksid=p3984.m1497.l2649 . The summit directions dont make sense unless I use the dist. block along with my prop valve. Instructions here I could figure it out on my own by trial and error, but if someone has some insite I would appreciate it very much.

Earlier progress pic from our build just for fun, we are getting alot closer to running now.
guts.jpg

ah64pilot

Here is the "improper" proper way to plumb a line lock with a dual function proportioning valve / distribution block:

MC (front brake line) to Line-Lock to proportioning valve. When you have the line lock engaged the factory "brake" light will light up in the gauge cluster notifying you that the front brakes and back brakes have a discrepancy. This tells you the line lock is working.

When you plumb it this way make sure you have a good bleed on the brakes as the differential pressure will offset the distribution block plunger isolating the back brakes. When you let off the switch, the residual pressure in the back system will push the plunger back into the "normal" operating position and turn off the light.

Look at my build link to see pictures of my installation and plumbing to get an idea:

https://classicoldsmobile.com/forums...umented-4.html

Team13Racing

Do the lines from MC to lock to prop valve and MC to prop valve ( for rear brakes) need to be equal length?

joe_padavano

No, not at all. One word of caution. If you have a factory cast-iron combo valve, replace it with a brass one. The bore in the cast-iron valve can rust. This can cause the differential pressure piston to stick when the line loc pushes it all the way to one side.

ah64pilot

Agreed. If you plumb it this way everything needs to be working properly. The brass valves are nice, that's what I have on mine.