Maybe it is because I own and drive a “stupidity” but I got to ask what the proportioning valve does, and why would it be different if you use disk brakes on the rear?

Chase, you will find if you haven’t already about 3/4 if not more of the bolts on your Cummins are metric. I only had about a dozen metric tools before I started working on the oil burner.

 

Not meaning to hijack the thread but, holy cow, I never knew this. Now I can see that we were beginning to see the shift to globalization from this by our own government and the elite. They wanted the big 3 to tool our cars so that other countries could build them instead of our factories building them. I wish that we could have stayed with the standard measurement instead of the metric system. I remember having to buy all new tools and special tools when I was just out of high school. Make the rest of the world conform to our standards. I grew up here based on American pride, American made, where did all that go? Did our Government really sell us out?

 

Proportioning valve essentially "limits" or "proportions" the mount of fluid or pressure sent to the front and/or rear brakes. Since truck rear ends are light (just a bed back there) in comparison to the front the rear gets less fluid. Now with disks they need even less fluid as they tend to "work better" than drums. Regulating the fluid or pressure sent to each end of the car/truck keeps the rear from "locking up" when you hit the brakes. At least that's the way I understand them and the best way I can explain it in simple terms.

Now - if you add disk brakes to a truck that had drums - the rears are getting more pressure/fluid than they need to stop the thing and you are more likely to have the rear brakes "lock up" on you.

This is why Ed's suggestion of the in cab proportioning valve makes such sense.

And on that note... Ed - I'm getting ready to do the brakes on both the Mutt and the Super. You got a good place locally to pick up the adjustable valves? Or do you just order online? Also - any personal preference between the handle style of **** style wilwood makes? I was thinking the ****/dial style might work a little better for my needs.

 

So I'm getting back to this because I messed with my hydroboost a bit more today.

I went to my local hose place to get some parts for my braided steel brake lines and while I was there I figured I'd try and get some adapters for the female ports in the master cyl.

When I went to remove the stock fittings coming out of the hydroboost (the guy cut the hard lines just beyond the fittings) I grabbed my metric set of line wrenches and they didn't fit. My 9/16" one did though...

Now this doesn't 100% guarantee that the lines are not metric - but it puts some major doubt in my mind.

When I went to the hose shop I just plopped the hydroboost/master down on the desk, pointed at the ports and said "I want fittings for these to convert to a male -3 AN" and they can out with the right size. They didn't comment on the fittings being metric or not - so that was not much help in solving our mystery.

 

WTF - double post.