I'm going through the engine compartment of my 69 and I've put new front brake lines on the car. I had some minor brake problems before I started the tear down of the car (brake light coming on in dash and pedal going from hard to soft). The proportioning valve looks to be okay but I wondered if this is a typical "wear item" that I should replace. Any way that I could test it?

I dont see that there is much to the mechanics of this thing. If these don't typically go bad I'll save the money and spend it else where. However, I prefer not to make any compromises on safety items.

 

Unless your '69 is different from mine, it's just a junction block down there, with a differential pressure switch to indicate brake failure on one end of the car. There's no movement of anything there in normal driving, so wear ought to be insignificant. I would expect you could flush it, bleed the system, and go.

 

I'm a little opinionated here. First of all I agree, that it's probably a junction block, not a distribution valve. Second of all, for a 69, my prejudiced, opinioned statement is get rid of the stock brake lines. Replace them with stainless steel lines. The brake lines on my 68 Corvette salt free California car, looked pretty good outside. Inside when I cut them to remove them, they had a reddish brown jell of rust. The stock lines are steel and they can rust from the inside out. I also ordered stainless steel fittings and all new brass blocks. (In-Line Tubing).

Also, you can replace all your brake lines with new stainless steel lines, without removing the body. The apparently trickiest line is the brake line from the master cylinder to the distribution block at the drivers side distribution block on the driver's side. At first glance it looks impossible. After having replaced this line three or four times, it's pretty much a piece of cake.........however.......in all my replacements, I had the trailing arm out. About 6 years ago, I posted detailed instructions on how to do this. I could go through this again, but my recollections for details may not be that sharp. On my 68, for the distribution block at the back of the driver's side trailing arm, I had to take a torch and bend a tubing wrench slightly to tighten up the fitting. On my 70, a stock tubing wrench fitted up fine. Maybe GM changed the geometry.