I recently salvaged the components for a disk brake conversion for my 68SS. Donor parts are from a 72 Sprint. I realize I need to purchase new rotors and either rebuild or replace the calipers. Where this gets confusing for me, is with regard to "brake valves". My knowledge of brake systems is limited so please bear with me. I have seen reference made to proportioning valves, brake valves, distribution blocks, metering valves, disk brake valves, combination valves, etc., etc. I simply want to know what I need to make these brakes function properly on my car, and what the correct name is for the "valves" I need. I have non-power drums now and would rather not add the power booster when converting to disks. My brake lines currently feed into a brass valve/block/metering device or whatever its called, and from there to the wheel cylinders. It looks like the first picture below. Is there an different piece or an additional piece that needs to be added inline somewhere? I also have a valve removed from a 69 Chevelle with drum brakes... see the second picture. And finally what is this in the third picture, and do I need one with non-power disk brakes?
Any insight is greatly appreciated.... Patrick
http://www.chevelles.com/showroom/Merlin/brakevalve.jpg
http://www.chevelles.com/showroom/Merlin/69drumbrake.jpg
http://www.chevelles.com/showroom/Merlin/diskvalve.jpg

Go to www.mpbrakes.com (http://www.mpbrakes.com) for a good discussion of what a combination valve is. Basically it is a valve that does a combination of things, such as hold some residual pressure in the rear brake lines so that the rear drums are beginning to brake immediately on depression of the brake pedal, as the front discs are ready to apply at this same time. Then the combination valve does some "proportioning" in that it delays sending some fluid to the front discs momentarily to allow the rear drums to take action. Again a function necessary in a front disc rear drum car.
A 4 wheel drum car will not have a combination valve, which some people call a proportioning valve. It will only have a distribution block with a warning lite. I believe your first 2 pics are distribution blocks only, as they do not show any button on the front, which is the tell tale sign of a combination valve. YOur last photo appears to be a "metering valve" used circa 1968-70 on front disc brake cars, like chevelle. It delays fluid momentarily to the front discs to allow rear drums to begin action.
I suggest you use a combination valve, which can be purchased new from GM or most chevelle aftermarket vendors, or pull one from a boneyard off a car about the same size and weight. YOur bullet metering valve is probably more correct for your year, but if you use an aftermarket master cylinder you won't have a residual pressure valve built into it, like they did in 66-70 approx. Hope this helps, but read what MP brakes says. Good site

Thanks Marley... will it be necessary/advantageous for me to replace master cylinder when I do the conversion? And am I correct in assuming that I do not have to use a power booster with disk brakes?
Thanks again... I'll visit that site.
Patrick

p.s. Just visited www.mpbrakes.com (http://www.mpbrakes.com) Outstanding site! Just what I was looking for graemlins/thumbsup.gif

You can have disc brakes without the booster, if space is the issue.

If you had drum/drum, you will need a new master cylinder for disc/drum. The volume of fluid needed to operate the front calipers is much more than the drum MC can provide.