Quick question: A proportioning valve like the one below needs to be installed AFTER the distribution block on the brake line which heads for the rear of the car, correct? Getting ready for a brake overhaul and couldn't find this simple information. Thanks!

http://www.allstarperformance.com/do...ning_Valve.pdf

 

Oh forget to mention this. So it seems that cars with factory disc/drum setups had a static (non-adjustable) proportioning valve directly after the distribution block. I understand that drum/drum cars did not have one. My car is factory drum/drum if that info is needed.

 

IMO that valve is to be used INSTEAD of the stock COMBINATION VALVE used on 69 Mustangs.

The combination valve may contain RPV's (residual check valves) as needed, proportion valve, and the brake safety system/switch (switch activates "brake" light on dash when either front or rear circuit fails in the m/c).

I want to say that as long as you are running RPVs and a proportion valve, the rest can go by the wayside. Some RPV's are incorporated in the output ports of the m/c, others are part of the combination valve, not sure which on your 69.

RPV's are sometimes OPTIONAL on disk brake setups with firewall mounted m/c, other time 2 psi RPVs are needed, on drum brakes 10 psi RPVs are required.

I guess the short answer is that you wont need, and won't WANT both the proportion valve and a combination valve (what you call the distribution block).

 

Yes the 67-69 valve was not adjustable (the 65-66 was).

Drum cars did not require one, but disc and drum require very different pressure, so they needed one to balance the system.

This is the 67-69 Mustang proportioning valve. Early 67's had it near the rear axle, but then it moved to the engine compartment, attached to the brake block.

 

oh well, see what I know...

I shouldn't have assumed that these cars have the kind of setup I am farmiliar with, I took the fruit jar off the 66, it didn't have much of anything other than a m/c and wheel cylinders...

 

Whoa so hold on.... I'm not sure if my question was answered. I know I need a proportioning valve, because my car was stock drum/drum (aka there is no proportioning valve built into the distribution block). So the question is: do I install the proportioning valve (for the rear brakes of course) BEFORE or AFTER the distribution block? My intuition tells me after, so that the PV has final effect on the pressure of the rear brakes. Anyone know? Here is a crappy picture of a non-aesthetically pleasing setup, but I think my lines will have to be ran somewhat similar: http://www.allfordmustangs.com/forum...disc-swap.html
The picture needs to be clicked on to be enlarged.

 

After. It regulates pressure, reducing it to the rear wheels. If it is between the MC and the warning switch, your waring switch will think the brakes have failed.

 

The valve shown in the link will function just fine in the rear brake line AFTER it leaves the stock distribution block.

Keep that stock distribution block, hook it up exactly as it was, all will work fine.

Dan @ Chockostang

 

If you're just overhauling your brakes, why would you need to change the pressures? New factory replacement parts shouldn't need any changes.

The valve you linked to isn't really a proportioning valve. It's usually called that for simplicity, though. It's really just a pressure reduction valve. Unless you're making significant changes to the system, there's no need to reduce the pressure.

Residual valves keep a little pressure in the wheel cylinders/calipers. It keeps the fluid from draining back into the master cylinder. Unless the MC is floor mounted, you don't need them.

 

Ok, on to something I do know, if you are running drum brakes you always need 10psi RPVs. (sometimes these are part of the m/c or combo valve)

For disk, sometimes factory disks run 2 psi RPVs, sometimes, not.

On drum brakes a rpv is needed to keep the springs from pulling the shoes all the way in causing a soft pedal on initial application.