The Stovebolt Site Forums The Shop Area General Truck Talk Combination Valve Question

I have followed with great interest the separate discussion that has been underway by RATRODKING on his conversion to power brakes and the various aspects of it. One item that still has me somewhat puzzled even after the information and associated link from Richard is the function, use and installation requirements of the Combination Valve.

In my particular instance I will be running an 8" dual diaphram power assisted 1" master cylinder http://www.mbmbrakeboosters.com/Mas...le-Cast-Iron-Master-Cylinder-1-Bore.html that I already have under the truck. I plan to keep the 6 bolt front set up, so I will be using mid 70's calipers and rotors from a Chevy Blazer that I purchase locally and brakets I already have from Buffalo Steve.

What I have not figured out is the best way to plumb this and how to determine what combination valve to use. My intial plans were to not use one, and just put an adustable one rear of the 10 lb residual valve for the rears, and run a 2 lb residual for the front and tee forward of that to the cylinders. Now however, it seems a combination vavle is a better idea, but what one do I choose? I have not been able to find much detail on differences, but I would think they would have to be designed for the particular application to account for vehicle weight and distribution? Also, do I need to 2 lb residuals since the combination valves seem to have separate outlets for each front wheel?

Thanks.

This is what you need. 10# residual to the rear, as close to the MC as possible, with an adjustable valve. Do some research so you know how to set it up and test it. 2# residual to the front, as close to the MC as possible. Run a single line to a metering valve. The metering valve has three ports, one in and two outs. One is for the right and one is for the left. Bleed your brakes and you are done.

Information here

57 vroom vroom, i was told that you dont really need the factory style combination valve. just use the 2lb front and 10lb rear residual valves and a rear proportioning valve, adjustable.

now that mine is working correctly, i dont mind it, but if i were to do it again, i probably would do without it, and its cheaper without it.

leonard

In hind sight I wish I would have know Buffalo had caliper brackets for 6-lug conversions. In all of the looking I have done, I did not find one caliper only kit for 6-lug.

I am about 6 or 7 hours into my CPP kit. The quality is junk. And I still have more blue printing to do. The rotors are made in China, and who knows who rebuilt the calipers. I am sure when they take a dump, I will not be able to send them back to CPP for replacements.

I thought I would be saving time by buying a complete kit. Boy was I wrong.

Lonnie

How are you going to mount the blazer rotors to your hubs? I have been trying to figure this one out and pretty much came to the conclsuion that by the time I bought or made brackets, had rotors drilled or machined and then gathered up the hardware, spacers and brake hoses, I might save $50 off of CPP's kit.

If the rotors aren't drilled spot on, you are going to have a huge imbalance of rotating mass.

Based on Lonnie's input, I'm now reconsidering, but I'd bet rotors from FLAPS or Rockauto are also made in China, at least the ones under $40. I'm pretty sure they use the same camaro caliper for 5 or 6 lug kits.

57_SS

The 4x4 rotors do not appear to have any machine work done to them, except for the 3-drilled and taped holes. As I do not know what comes with the Buffalo kit, I cannot comment on it. But an adapter plate is required to bolt through to the rotor. If this plate is not included with the Buffalo kit, you are right in that there would not be any savings.

The three drilled and taped holes in the rotors are matched to the three rivit holes in the stock hubs. One of the problems I have had with the CPP kit is that the adapter plate counter sunk holes did not match the holes in the rotor. I had to fill them with weld and re-drill and counter sink them. This process alone has taken me about 2 hours per plate.

The other problem I had was the caliper brackets were not bent correctly. After spending an hour or so figuring and measuring to see where everything needed to be, it took me a couple of hours of bending and tweeking to get everything offset correctly and the calipers in the same plane with the rotors.

Lonnie

Lonnie,

I would have sent it back, that sounds terrible. I bet you bought it a while ago and figured its yours now, I wonder if they count on that. I'm surprised the rotors are taped. I figured nuts inside the hubs. (might not balance out, I guess)You cannot find off the shelf Chevy 4x4 rotors that have the 3 holes in them that line up with our hub to drum rivets. That's the machining/drilling I was referring too. I thnk CPP or others sell the spacers for 25 a pair. Once I found that, it became a reality to do. McMaster_Carr carries countersunk head bolts. The One idea I had for home made brackets using flat plate was to weld on tubing to achive offset. Do you think that would work? Over at Chevytalk.com there is a forum just for CPP, you could at least ask why your parts were so QC poor and then others would see your post for eternity, right?

guys,
seems like eveyones complete brake kits are all of questionable quality.
mine is from performanceonline. i have seen them in the car and truck magazines for years, and thats why i went with them.

my problems were::
1--caliper mounting bracket that bolts tot eh spindle needed major grinding on the inboard area where the caliper slides on. the back of the inboard pad rivets were bubbing and preventing the caliper from sliding on.

2-- then i had to grind a hump off the middle of the caliper that was coming into contact with one of the spindle bolts, causing it to not bolt onto the caliper bracket, had to grind both calipers, drivers and passenger side.

3--the bearing spacer that slides onto the spindle first, so the new rotor and tapered bearing will work, i had to take them both to work and chuck them up in the lathe and bore .003-.004" out of the I.D. so they would slide onto my spindles.

4--banjo washer leak on drivers side caliper. luckily i got it fixed, since i was searching all local auto parts stores and theres were not any better looking.

5--major thread slop on the same drivers side caliper bleeder screw, preventing me from getting a good bleed when cracking the bleeder when bleeding that wheel. finally figured it out and wrapped it with some teflon tape, then when cracked for bleeding it would not suck air, so it worked fine after the teflon tape.

6--had to bench bleed the master twice.

7-- had to take the new master cylinder piston out and re-install, because hte was taking up to 2 minutes to return to home position against the snap ring.

8-- had to fab a combination valve holder to keep it in the neutral position when bleeding so it would not kick off one side or the other.

those are the problems i ran into with my 900 dollar complete kit !!
and when i asked tham about returning the master, he said i would have to send back tothe manufacturer who is in another stae, let them look at it, and if they can fix it, fine. if not,t hen they woudl send me an new one.
i told the guy he has got to be kidding me. i aint gonna wait another 2 weeks because of something they have a problem with.

the guy called me back, saying another tech there had a customer witht he same problem, and suggested me to go by another master cylinder from my local auto parts dealer, he gave me the raybestos part number, and take the guts out and use in mine, take the suspected bad guts from mine, put in the store bought master, and return for a refund !!!
can you believe that crap ? they will be hearing from me very soon about quality and customer service returns.

my master, booster, rotors are all brand new, and the rotors actually look better quality than any i have seen, and have a nice cross hatch on the surface.

the rotors and calipers are stock 1970-1978 camaro, so it will be easy to find replacements when they wear out.

mine is working fine now that i had to work my butt off fixing their screw ups, and it breaks very good, even better than my factory 2--3 s-10 actually.

so as others have suggested here, i would but the caliper brackets, bearing spacers, master cylinder frame mounting bracket, then get the rotors, calipers, master, from a local auto store. that way if there is a problem with them you can return them and get another that same day while you are standing there.

hind sight is always 20/20, and man, i wish i woudl have listened to my buddy dave who told me to do it that way.

and he never runs the factory combination valve, only running a rear prop valve with residuals in fronts and backs.

hope this helps any of you trying to do this same install.

leonard

Hi Guys,

Well this has shifted a bit off the subject I am really interested in, which is if and how to use a combination valve and if and how an adjustable vavle fits in. I am sure we will get back to that at some time!

Anyway, since everyone is asking about the 6 bolt disc 'kit' from Buffalo, I scanned a couple sheets he sent me to my collection of photos. I am hoping this is ok, as this is the type of information I would would expect to see on his website... In my case I did not get the spacers, as I do not think I need them since I am currently running alum wheels without issue. As I understand it, that means I do not have to perform step #5, which would require drilling and tapping the holes to allow the spacer to sit outboard of the rotor.

vroom vroom, now i am confused. LOL.

i am talking about bearing spacers, not wheel spacers.
are your 6 lug rotors using the factory style ball bearings ?
if so, then i guess you might not need a bearing spacer.

mine uses the newer roller type wheel bearings and you need a bearing spacer that slides onto the spindle. it wont work if you dont.

i was told by the place i got my kit, and other people, that yes, you can use an adjustable rear prop valve along with the factory style combination valeve. that is exactly what i am currently using now on my 57.

in problem #5 from my previous post, i am talking about just the bleeder. the threads that the bleers screwed into was worn, and i had to wrap it with teflon tape to get it to not leak air when i cracked it while bleeding.

hope this helps, and make certain your 6 lug rotors are capable of using your old bearings. i ahve never heard of that, but i could be wrong. that is another advantage, having newer style roller bearings. they hold up much better to the radial tires and road conditions we have today.

leonard

here is the bearing upgrade kit..

http://www.performanceonline.com/store/customer/product.php?productid=16632&cat=1073&page=1

and here is a pic of the bearing spacer installed on my spindle.
the factory spacer has a totally different dimensions then this new one. if i were to try and install the newer rotors on the old bearing spacer, i would be in real trouble.

http://s251.photobucket.com/albums/...00/?action=view&current=DSC01550.jpg

leonard

RATROD,

Sorry for the confusion, guess that is what happens when several different conversations at once!

I am using my existing hub, and new tapered bearings from CPP http://www.classicperform.com/Store/1947_59_Trucks/4759RBK.htm that look to be the same as what you have. I replaced one side late last year when the original roller bearing race decided it had had enough and started to drop the bearings about a mile from my house. I can tell you there are not any spacers required, I removed the old ball races and seats and then installed the new ones in less than an hour. Here is a link to those interested http://www.classicperform.com/tech_articles/Tapered-Wheel-Bearings/Tapered-Wheel-Bearings.htm

I have kept a close eye on the other side, and hope to make it through this summer and then swap it out when I do the disc brake upgrade.

Here are the pictures of my problems with the CPP kit.
pictures

wow lonnie, those are some serious problems with te cpp kit.

didnt really notice any of those problems with my performanceonline kit.
but did notice a little humming type noise from the passenger side front rotor when braking, sort of like maybe the caliper was putting pressure unevenly on the rotor, or something to that effect.
seems to eb fine now, and the rotors and bearings do not heat up after a nice 60mph cruise, so i think everything is good, i hope.

you would think the money we pay for these kits, and as many kits as these places have sold, you would think they could get it right, but i guess not.

leonard

leonard

For anyone that thinks they want two proportioning valves, they might consider looking at this pressure chart.
Proportion valve pressure reduction

I'm sure you understand that the pressure from the master is always equal, for front and back. Two pistons the same size, moved the same distance at the same time.
The first thing you see on the chart is that below about 250 the pressures are the same. 250 to the front brakes, 250 into the proportion valve and 250 out of the proportion valve to the rear brakes. The rear of the first Camaro's were pretty light so heavier cars may have equal pressures(in and out of the valve) up to a higher level.

Looking at the chart at 1000psi, you see that after the prop valve(combo valve in ratrod's case) you get 600psi. If instead of sending the 600 to the rear brakes, you sent that to a second prop valve. Look at the chart. 600psi into a prop valve produces about 400psi. You now have 1000psi to the front brakes and only 400psi to the rears. Even if the second prop valve is adjustable, you probably can't adjust the pressure up to what you should have for the rear.

Guys here is the scoop on bearings. King is doing a 5 lug conversation so a sleeve is used over the spindle for the inner bearing. That is what he had to machine to fit. He does not reuse the stock hubs. His rotors have intergal hubs and mount right onto the bearings. Vroom & Lonnie are doing 6 lug conversations. They retain their orginal hubs and use studs or bolts to mount a rotor to the hub. To get tapered roller bearings, the kit linked to above is purchared separatly.

yea, 57 stepside has got it right.

vroom vroom,
when you actually do go to front disc, im sure you will then need the bearing spacer i had to get.

richard,
i installed the wilwood adjustable rear prop valve into the system, IN CASE i would need or want to fine tune the rear brakes. it can be adjusted at fully open, 100%, to fully closed it will cut off the back brakes 57%. so i can fine tuen it anywhere from 100% down to 57%.
right now i have it fully open at 100%, an dhave not dont any panic stops to see how it will handle, but since i was replumbing, i would have hated to find out i possibly needed to fine tune the rear and not have it in the system, so i spent the extra 40 bucks and put it in the rear system, just in case.

hope this clears things up guys.

leonard