Proper front brake line routing on '72

[joeydurango]

'72 K10, power disc/drum. New master cylinder and proportioning valve. When we put the new prop valve in, we realized there was an extra port that wasn't being used on the upper front of the valve (on the old one too) - basically, both front brakes are run off one line. It runs from the lower front port on the prop valve to a T-junction, then to both front calipers.

My questions are two: Shouldn't there be two distinct lines, one from each forward port to each front brake? And assuming that's the right way to do it, wouldn't that provide a lot more braking power, since with the single line/T-junction setup it's only moving half the amount of fluid to each caliper?

It works okay now. I just wonder how much better it would work with separate lines. Does anyone know from experience? Thanks!

[CUSTOM/10]

I just finished doing my brake lines ( 72 K10 ) It came stock from the factory with one line down to a tee inside the frame rail then from the tee to ea, wheel. Some of the earlier trucks had two lines right from the P-valve, but I believe those were drum/drum trucks.

Gary

[CUSTOM/10]

Yours look something like this ? This is all new Booster & P-valve.

[joeydurango]

Yep. The forward line out goes to a T, then to both front calipers. Right?

Surprised that's the stock routing. I think that's probably the same new prop valve I have. What's the plugged, upper-forward port for, if not a second front brake line? It's not a bleed screw.

[CUSTOM/10]

I believe the P-valve is universal, so it could be used on a dual front line set-up or single. I believe you could run a dual set-up, but I don't think you'll gain anything ! Factory on a 72 was single 3/16" for the front, 1/4" for the rear.

Gary

[knomadd]

I ran a similar prop valve and dual front lines on my GTO several years back, not knowing the port could be plugged. It was a nightmare to bleed properly. I had to have a shop pressure bleed the system to get the final bit of air out. Since the line starts off going up, the air tends to stay put. if you mounted the prop valve sideways with an under mount bracket, this wouldn't be an issue.

I've never changed it, since it seems to work fine, but I bet it doesn't make much of a difference.