whats the correct CPP proportioning valve for 4 wheel disc
 

Mann, CPP has some crappy crappy customer service. ill skip to that later.

so using their site its confusing so i just ordered it from Summit. I used their filter and when rear disc is selected the brass version
PV-24BH is shown, but only shows "Brake Proportioning Valve, Fixed, Brass, Natural, Each" as the description and CPP only says Black GM-style prop valve, ea. for similar PV-24BBH.... which may be Black Brass Housing - BBH??
on top of that confusing non sense, the photos are generic across summit/CPP/ and even ebay with cpp selling it..

either way, on their site it seems any PV-2 is a disc / drum application and any pv-4 is disc/disc

called summit and got through pretty quickly and unfortunately he basically did what i did.. use the drop down menu... needless to say im not confident in putting this on, not for a lack of quality, but lack of confirmation that this indeed is for disc/disc. Ive ran the stock prop valve with 4wheel disc for last 7 years no problems but was like why not get one ment for the task...

super frustrating to hang on the line for 30+ minutes -CPP- to specifically get a person to talk to instead of pressing the button to leave a message that they probably wont even return only to get to the point where the phone rings and ... and... leave a message... emailed them yesterday and still no reply.

and the quality on the prop valve tool to keep the valve centered is a joke.. like for real, a JOKE. threads are smaller diameter than the actual switch so its reminds me of a stick shift car with worn out shifter bushings... at first i thought somehow it was cross treading, but nope, miked it and its threads are .015 smaller so it just wiggles inside untill it touches the valve... it basically wedges its threads against the prop valve threads..

Re: whats the correct CPP proportioning valve for 4 wheel disc
 

I know this is no help to you but with all the bad reviews I don't know why people still give them business. I bought a tilt column a few years ago and when I installed it it blew fuses every time I turned on the key. Pulled it apart and all the inerds were not hooked up! Screws and springs dumped inside of it and shorting out the fuse's. I will NEVER buy from them again, sorry for the rant.

Re: whats the correct CPP proportioning valve for 4 wheel disc
 

Yep, gonna return their product.. after logical deduction on ther part number and off of knowledge of what's inside a combination valve.. the pv-24bh is a mearly a stock combo valve with a removable metering valve and prop valve
.. just like stock, and an optional plug, that's needed to. e purchased, to replace the meeting valve in the front brake circuit... disc disc doesn't need a meeting valve so.. returning it!
All of cpp pv-2 products say disc drum
All of cpp pv-4 say disc disc..
Am I gonna buy a cpp pv-4.. crap no.. gonna go with a different brand.
Clint

Re: whats the correct CPP proportioning valve for 4 wheel disc
 

I might suggest an adjustable prop valve similar to something like this, https://www.summitracing.com/parts/s...CABEgKsV_D_BwE

Re: whats the correct CPP proportioning valve for 4 wheel disc
 

Only way CPP will ever change is if people stop buying their stuff. I'm honestly considering talking with them at SEMA this year. I've passed them over on a few projects now because their service sucks so much.

Re: whats the correct CPP proportioning valve for 4 wheel disc
 

I don't know if it is correct but this is the proportioning valve I bought after doing research on my disc/disc swap. I haven't installed it yet.
https://live.staticflickr.com/7917/4...eaa2a6fe_b.jpg

Re: whats the correct CPP proportioning valve for 4 wheel disc
 

That's the one I had exhangednthe cpp one for. Also returned their cheesy prop brake bleeding tool for the summit.. should be here today.

I did get a call back from CPP and they said the pv24hb works with disc/drum or disc/disc... doesn't make sense to make it for both..
Clint

Re: whats the correct CPP proportioning valve for 4 wheel disc
 

Hopefully it works for you (so I know it will work for me)

Re: whats the correct CPP proportioning valve for 4 wheel disc
 

I'm a little hesitant to comment here, but it needs to be said, so here goes. (and I'm not knocking any one company, all are equally guilty)
Pictured here is a "Metering Block" often mis-named as a Proportioning valve (not the same thing). Metering blocks are common in production cars around the world. Large auto makers spend BIG $$$$ to get this correct. There engineers take a lot of variables into account. Vehicle weight, weight balance, wheel base, tire size, CG height, load capacity, master cylinder size, boost type, rotor dia., caliper bore, front/rear bias, drum dia., wheel cyl dia., ........That's what it takes to match up a production metering block.
Now think about your truck. If you are restoring (really back to original) then yes, use a metering block. But, if you are modifying, what vehicle does your truck now match? A Chevelle? a Camaro? an LTD? - That's what they are selling you. They typical 4wdisc metering block being sold is from a 1982-1992 Camaro. So what should you do?
Stop putting "Stocky" solutions in custom build situations. Here is a foolproof 100% solution system for any custom brake system.
1. Throw out the metering block
2. Accept that you will need three (yes 3) valves. And it will cost you $100
3. You need two (2) residual check valves. One in the front line, and one in the rear line. Use a 2lb. valve for disc brakes, and a 10lb valve for drums. - YES, even if the master is up on the firewall.
4. You need an Adjustable Proportioning Valve (Wilwood, Summit,....) This will go in the rear line.
5. As a rule, the valving should be closer to the master cylinder. As close as reasonable. I usually use a 12" line from the master to the valves. In the rear line, the Check valve and the Proportioning valve can be joined using a pipe nipple to make plumbing easier.

Why do it like this? You want 100% of the front brakes available. You can modulate this with your foot when you learn to drive. Most truck will have too much rear brake. The Prop valve can be used to reduce the rear brake, and adjust the balance to your custom build.
Will Metering blocks work? yes. As well as a non adjustable carb. Will you get the best brakes you could have? NO.
OK, didn't mean to rant. We fix and re-plumb 30 to 40 cars and truck every year. well built big $$ projects that don't stop. We follow the same rule every time, and every time it works. I hope this info helps at least some of you guys. Have a great day.

Re: whats the correct CPP proportioning valve for 4 wheel disc
 

Off topic, and I apologize, but why do you need residual pressure valves if the m/c is mounted on the firewall? Trying to gain an understanding, not questioning your methods, by any stretch!!

Re: whats the correct CPP proportioning valve for 4 wheel disc
 

Good question, and by all means, question away. Here's what a RCV (Residual Check Valve) does. It's kind of a one way valve, all of the fluid flow and pressure can go one way, "To the caliper or wheel cyland when the delivery pressure is gone, all of it can return (to the master) until the pressure drops to a certain level (2lb or 10lb). So, why do you want this?
There are forces trying to push the fluid back to the master, and you want this to happen, to a point. You lift you foot, line pressure drops, the pads or shoes relax, that's the pressure force, drums have big return springs that would continue to push fluid back until the wheel cyl was completely in, - some High performance calipers have return springs as wee. Then, the heat differential comes in, hot fluid pushes towards the cooler fluid, and lastly, any run out in the rotor or drum, bearing slop, axle or spindle flex, caliper mount flex and other forces are all trying to push the fluid away from the caliper or wheel cyl. But you don't want that to happen. You want the pads or shoes to stay as close to the brake surface as they can, without (or with very little) contact. That way, next time you hit the pedal, the brakes are nice and consistent and high. the same every time. If you hit the brakes once, and then quickly release and hit again, and the pedal is higher, you have too much fluid returning.
So, even up on the firewall, the drum style return springs can easily push fluid up against gravity, and the heat and run out of the rotors can do the same. The residual valves will let the fluid come back, yet hold enough in the lines to overcome these additional pressures. Hope that makes sense.

Re: whats the correct CPP proportioning valve for 4 wheel disc
 

Well said.

As a former brake development engineer for GM truck you posted exactly what I was thinking.

Those valves are just a shot in the dark unless you know the meter/split/slope information based on their internals.

K

Re: whats the correct CPP proportioning valve for 4 wheel disc
 

Thank you Mr. Rob! You wouldn't have a pic or two you could post up showing us what this looks like? Sincerely appreciate all the time you've invested in educating us! :metal:

Re: whats the correct CPP proportioning valve for 4 wheel disc
 

Thanks everone for input, super awesome content here. That's one side buying off the shelf parts is the total package outcome. In my case I was looking merely to eliminate the meterng valve since I think indont need the extra rear brake apply before fronts. I just got the truck back in the road after the gen 5 swap and felt like turning the rear rotors since there was a minor rust ring from the non contact area / lip of the rotor.. hella run out. No measurements before but it went from inspec dimension to minimum thickness after 6 passes to clean up... bummed about it I bought we rotors for next brake job and cpp valve.... returned the cpp valve, then the bought the summit non metering valve variety.. overall, truck always seemed to stop fine with stock fronts and my c5 rear brakes.. I just wanted the proper proportion valve..

Clint

Re: whats the correct CPP proportioning valve for 4 wheel disc
 

My understanding of these valves is to keep either 2lb (disc) or 10lb (drum) pressure on all the time, to prevent pad or shoe retraction. It is not enough to apply the brakes but enough to keep them expanded to take up any "slack".

If it was to allow all the fluid to return to the master, it really is preventing the idea of a check valve.

This is right off Wilwood's site,

"Wilwood's two, four and ten pound residual pressure valves retain a minimum brake line pressure to help eliminate excessive pedal travel in both disc and drum brake systems. The two pound valve is used in disc brake applications where the master cylinder is mounted below the horizontal plane of the calipers and fluid drain back occurs from gravity and vibration, thereby causing excessive caliper piston retraction and a longer brake pedal stroke. The minimal two pound residual pressure prevents fluid from flowing back without causing the brakes to drag. Four pound valves can be beneficial in high vibration brake sytems such as off-road or dirt circle track racing. With drum brakes, a ten pound valve is used to compensate for return spring tension and maintain wheel cylinder sealing in the drums."

Re: whats the correct CPP proportioning valve for 4 wheel disc
 

Finally decided to install the summit racing 4 wheel disc prop valve. Everything fit pretty well. Had to tweak the lines ever so slightly. Their bleeding centering tool fits so much better than cpp.
End result... need to install a manual adjustable valve. Doing the 25mph to 0 in 20feet the rears lock up on dry concrete towards the very end. Side note, never did the same test prior to the valve swap.. oh well.

At work we got the state inspection brake test striped off.. so used that for a reference. Brakes feel great otherwise... never had a problem but think the stock setup was causing the rears tonwarp did to them being used more to slow the truck down before the fronts.. maybe.. dunno..

Xlint