Proportionate valve or distribution valve
 

This may be a stupid question, but I don't know the answer and don't want to screw up a little thing. I am doing a front disc conversion on my 70 c10 and don't know if this valve will work with my disc brakes. Thanks

Re: Proportionate valve or distribution valve
 

Not a stupid question at all. That's a distribution block for drums/drums. When you convert to front discs, you'll want to change it out to a proportioning valve. I believe you should also change the MC but let's see what others have to say. MC for front discs uses a larger reservoir for the discs and a smaller reservoir for the rear drums.

If you want to get picky, the front discs, which operate at higher line pressure (the reason for the prop. valve) use 3/16" lines, and the rear drums retain 1/4" lines.

Re: Proportionate valve or distribution valve
 

Ok, thanks for the response. Next question, where is a good place to get one for my application?

Re: Proportionate valve or distribution valve
 

Look at that steering shaft! Dang it man.


http://67-72chevytrucks.com/vboard/a...1&d=1428636260

As far as the P/V order any ones for a disc to drum. You can get them at a good parts house to. When I did my rear disc swap I had CPP send me one with their kit.:chevy:

Re: Proportionate valve or distribution valve
 

I don't get it about the steering shaft. I took it loose to clean the steering box and the frame. Is there something wrong with it as well?

Re: Proportionate valve or distribution valve
 

it should be more to the outside of the frame, in between the frame and left outer wheel house,and there is a small sheet metal brace that captures it if the rag joint fails.....but if you disconnected it, that explains it....
Ben:metal:

Re: Proportionate valve or distribution valve
 

Yes, I have it just sitting on the frame right now. I found this one on ebay. Would it work for my application? Thanks

http://www.ebay.com/itm/191444504548?redirect=mobile

Re: Proportionate valve or distribution valve
 

Ok that explains it about the shaft. I just noticed it and man! if you took it loose then your fine. Whew I thought you where driving it like that.
:lol:

Re: Proportionate valve or distribution valve
 

Yes that should work just fine. As long as it is for disc front to drums rear your good. :chevy:

Re: Proportionate valve or distribution valve
 

Next question. This valve has 2 inlets and 3 outlets, while my current valve only has 2 outlets. What do I do about that?I only have 2 sets of brake lines. One that goes to the back and on that T's off for both sides of the front brakes. Thanks

Re: Proportionate valve or distribution valve
 

+1. When converting from drum/drum to disk/drum, you must replace the master cylinder and proportioning valve for units designed for disk/drum applications. The disk/drum proportioning valve also acts as a residual valve, so don't need to add those.

I did a drum/drum to disk/drum conversion (and added power as well) to my '52. You can see the proportioning valve that I mounted to the frame (on left of photo).
http://i979.photobucket.com/albums/a...veplumbing.jpg

Re: Proportionate valve or distribution valve
 

I figured out the extra outlet problem. Thanks

Re: Proportionate valve or distribution valve
 

What about in '71? Just rebuilt my MC a few months ago, both front and rear reservoirs are the same size. I supposed an accurate question would be: "Did this change occur the same time they went to discs?"

Regards,
Mike

Re: Proportionate valve or distribution valve
 

>> both front and rear reservoirs are the same size<<
On drum brakes as the shoes wear down, the owner periodically readjusts the shoes or it may have automatic adjusters. The fluid level in the reservoir stays about the same when the shoes are new until they are worn out.
Disc brakes have no adjustment for pad wear. As the pads wear from new, the fluid level slowly lowers and the volume of fluid behind the caliper piston slowly increases. The manufacturers use a larger volume reservoir for discs just in case the owner never checks the fluid levels. They don't want the brake reservoir to empty before the pads wear out and the screechers alert the driver. Most new cars have fluid level switches in the reservoir and idiot lights, because they know the drivers are too stupid to check the brake fluid on their own.



>>The disk/drum proportioning valve also acts as a residual valve, so don't need to add those.<<

Most Combination Valves, which include a proportioning sectionDo Not have residual valves built into them. Residual valves are very important on frame mounted Master Cylinders, because anytime the MC is below a wheel cylinder, gravity will push the fluid back into the MC and air will be drawn into the wheel cylinder or caliper .

I hope you don't snag those low hanging brake lines.

Re: Proportionate valve or distribution valve
 

I called the cpp tech line yesterday to ask them about it. They said, that's I didn't have to change out the master cylinder. The one that's came with the booster I bought from them a few years back would work just fine. I did order the proportion valve off eBay and am waiting for it to come in now. On a side note, the cpp people charge $10 difference to get a booster with a proportion valve and one without, but charge $75 to buy one by itself with the bracket. I am not a mathmatologist, but that's doesn't add up to me.

Re: Proportionate valve or distribution valve
 

Just going off my memory of working on my '72..... apologies if it's not quite accurate, but that's how I recalled it.

Re: Proportionate valve or distribution valve
 

I finally got an email from Cpp, after 2 weeks, and that guy said that I had to change the master cylinder out as well. This is different than what the other guy told me over the phone. I checked the master cylinder that I have, and it does have a larger front cavity than the rear. I got in my proportion valve the other day. Should the master cylinder I have work?

Re: Proportionate valve or distribution valve
 

Now cpp is telling me that the drum/drum master cylinder is valved completely different than a disc/drum master cylinder. I don't know what to believe from them now. Dang it.

Re: Proportionate valve or distribution valve
 

I just pulled a mastercyl with booster from an 85 c10. used the lines from it and the proportioning valve, check out page 2 & 3 of the build thread in my signature. I used the entire front suspension and brake system from an 85, and then just got some couplers to hook the brake lines to the rear.

Re: Proportionate valve or distribution valve
 

From my post above, the size of the reservoir has absolutely nothing to do with the operation of the brakes, Nothing. It only becomes an issue if you never check the fluid level.

Re: Proportionate valve or distribution valve
 

I found this article helpful when I was setting up my brakes.

http://www.how-to-build-hotrods.com/brake-system.html

Re: Proportionate valve or distribution valve
 

That is because CPP is a joke. Shop elsewhere

Re: Proportionate valve or distribution valve
 

I have 3 guys there telling me 2 different things. 2 say it is fine, 1 says no. Pretty upset at this point. You would think the tech people would be on the same page.

Re: Proportionate valve or distribution valve
 

Now the proportion valve I ordered doesn't fit my brake lines. The hits just keep on coming. Cpp still has conflicting tech support. Not sure what to do at this point.

Re: Proportionate valve or distribution valve
 

Honestly, I don't deal with CPP for reasons like that. Their tech support is inconsistent.

Lets try and assess what you have, and what you need.

Why won't the lines fit? Are the lines too big, too small, wrong threads, not the right shape?

What CPP master cylinder do you have mounted on your truck right now? Is it from a disc conversion kit? Drum/drum? Do you know the bore size in it?

Do your best to be as informative as possible when describing the parts, model numbers, and issues you have with the parts- the more information we have, the easier it is to help get you on the right track. Best of luck. :metal: