68 camaro proportioning valve (combination valve)HELP?

[72Z/28]

Hi Guys

I have new front 6 piston wilwood calipers, new wilwood floating calipers for the rear installed last weekend, and Wilwood master cylinder, which was installed by the previous owner. I recently replaced the old distribution block with a combination valve or proportioning valve similar to the photo attached below

http://s218.photobucket.com/user/72Z28/media/image_zps5prnnf9h.jpg.html]http://i218.photobucket.com/albums/cc115/72Z28/image_zps5prnnf9h.jpg[/URL]

I filled the master cylinder with brake fluid and disconnected the flexi lines to the calipers in order to flush the system (Gravity Method) . However, I realized that NO fluid was passing through the combination valve.

So I need your advise on this issue and what should be done to resolve it.

Thanks in advance

[72Z/28]

So nobody is using this type of proportioning valve??!!

[kevmurray]

I dont have the one in the photo (what make is it?) but I have some thoughts. I wonder what happens if you disconnect a valve input line? Does fluid begin to gravity feed out the line? If not your master may not retract enough to open the ports to the resevoir. This might be a rod that is too long for your application.

If fluid does come out then it must be something to do with the valve. A true combination valve will hold off the front disc callipers so that pressure can build up in the rear (to get rear drums working before bringing in the front brakes). Maybe this explains the front not bleeding, is the rear not bleeding either?

With the valve lines connected can you step on the pedal to see if the increased pressure gets the fluid moving?

[72Z/28]

I dont have the one in the photo (what make is it?) but I have some thoughts. I wonder what happens if you disconnect a valve input line? Does fluid begin to gravity feed out the line? If not your master may not retract enough to open the ports to the resevoir. This might be a rod that is too long for your application.

If fluid does come out then it must be something to do with the valve. A true combination valve will hold off the front disc callipers so that pressure can build up in the rear (to get rear drums working before bringing in the front brakes). Maybe this explains the front not bleeding, is the rear not bleeding either?

With the valve lines connected can you step on the pedal to see if the increased pressure gets the fluid moving?

Well the only item I changed is the combination valve. Earlier there was a normal distribution block and fluid was flowing normally via gravity without any obstruction. I am not quite sure if the valve can be adjusted

[Sieg]

So nobody is using this type of proportioning valve??!!
Does that block have the ability to adjust the amount of fluid pressure to the rear brake line?

If not it's a distribution block.

This is how I plumbed my manual system with a Wilwood combination distribution & proportioning valve mounted below the master cylinder. I also incorporated the OEM delay valve just because. The master cylinder was bench bled following the instructions available on Wilwood's website prior to installation.

http://photos.smugmug.com/photos/i-2pZdD48/0/XL/i-2pZdD48-XL.jpg

[Vince@Meanstreets]

Is the master bled? what about when you push the brake pedal down?

[72Z/28]

Does that block have the ability to adjust the amount of fluid pressure to the rear brake line?

If not it's a distribution block.

This is how I plumbed my manual system with a Wilwood combination distribution & proportioning valve mounted below the master cylinder. I also incorporated the OEM delay valve just because. The master cylinder was bench bled following the instructions available on Wilwood's website prior to installation.

http://photos.smugmug.com/photos/i-2pZdD48/0/XL/i-2pZdD48-XL.jpg

It is a valve from Right Stuff Detailing:

http://i218.photobucket.com/albums/cc115/72Z28/Mobile%20Uploads/image_zps0y6rwsdy.jpg (http://s218.photobucket.com/user/72Z28/media/Mobile%20Uploads/image_zps0y6rwsdy.jpg.html)

I disconnected the inlet lines to the valve, and barely little brake fluid passed from the master cylinder ports. I also installed new rear brake line. My guess is the system is full of air as well as the master cylinder itself through which the fluid is not passing to the valve.

[72Z/28]

Is the master bled? what about when you push the brake pedal down?

Most like air is trapped inside. I disconnected the flexi lines to rear calipers,pushed the brake pedal down and noticed bubbles inside the master cylinder with the lead off.

Is this the reason why fluid not going through the valve or even through the MC ports while lines to the valve are disconnected?

[Vince@Meanstreets]

Most like air is trapped inside. I disconnected the flexi lines to rear calipers,pushed the brake pedal down and noticed bubbles inside the master cylinder with the lead off.

Is this the reason why fluid not going through the valve or even through the MC ports while lines to the valve are disconnected?

I believe so. You have to get some of the air out to get fluid to flow. Especially the master cylinder. Once the master goes dry you have to bleed it again.

Bench bleed the master, then hook up the feed lines to the prop valve then bleed after the prop/combo valve.

[72Z/28]

I believe so. You have to get some of the air out to get fluid to flow. Especially the master cylinder. Once the master goes dry you have to bleed it again.

Bench bleed the master, then hook up the feed lines to the prop valve then bleed after the prop/combo valve.

Since the MC already installed on the car, can I do the bleed without removing the MC,if possible, How can I do so?

Thanks in advance

[Vince@Meanstreets]

depends on the type of bleeder system you have. What did you use to bleed the master cylinder?

[GregWeld]

To bleed a Master Cylinder -- it is best to be removed from the car --- mounted in a bench vise by one "ear"... I use SOFT JAWS to do this so I don't mar the ear with the vise -- Then you hook up short lines from the ports that go back into the fluid reservoir - and make sure they are fully covered with fluid so when you back stroke they can't suck air -- Then I use a large philips screw driver to drive the piston ALL the way forward many times until no air bubbles come out your lines... You'd be able to see any air as it bubbles out of the short lines you created that are down into the fluid reservoir.

The reason you don't do a MC bleed ON CAR is because you can't drive the piston forward enough with the brake pedal ---- and you can't see into the reservoir while sitting in the car pumping the brake pedal.

Typically this job is done when the MC is first installed --- but I've found lots of people that SAY they did this -- only to discover they actually had no clue what "bench bleeding" is.

Wilwood ships bench bleeding hoses with their master cylinder -- if you still have those they're handy -- although I made my own up out of old brake line and fittings.


Once you get done with that job -- you can then continue on to bleeding your brakes. Bleed them by cracking the furthest brake from the MC -- which would be the passenger REAR -- have someone push on the brake pedal as you crack the bleeder... and have them HOLD the pedal down as you then just snug the bleeder tight - have them push and hold again as you repeat the cracking of the bleeder and tighten and so forth. Making sure you check the MC fluid levels as you do this -- don't let it get to far down! When you get some fluid -- move to the driver rear -- repeat the process - then to the passenger front -- then the driver front........ when you're pedal starts to "firm up" -- repeat the bleeding process once again with the passenger rear and so on.


The pedal should come up quite firm and be able to be pushed on with all your might and it should not go down one iota! And NO air should come out the bleeders at all.

NEVER use old or opened brake fluid! Use brand new just opened fluid for all this process. Don't try to save the fluid that is being bled - it's a CONSUMABLE -- toss it.

Some times I tap (that's gently!) the calipers with a small dead blow hammer as I'm doing all of this in an effort to "shake" any air in the piston area out (bubbles SHOULD float to the top where the bleeder is - in theory anyway).

[GregWeld]

Now -- here's the problem with buying a "one size fits all" proportioning valve...


Those valves are usually specific for a car - as it left the factory. Well ---- as it left the factory it had bias ply skinny tires.... Now days we have staggered tire sizes... with big fat ones out back and fat nice ones in front...and or we also have different rotors and calipers on than came from the factory.... so now the brake bias is all wrong for what we currently have on the car.

Thus -- most people around here (performance enthusiasts for lack of a better term) will put on an ADJUSTABLE PROPORTIONING VALVE -- which, obviously, can be adjusted so that the bias will be proper for the car it's installed in.

The last thing you want to have happen is for you to need to panic stop, god forbid it's wet out -- and you lock up your rear brakes and have the ass end swap with you. Thus the need for the proper ratio of front braking power to rear braking power AKA a brake proportioning valve.

Wilwood will be happy to sell one to you -- along with a mount (if you want to use theirs) and instructions... The proportioning valve ONLY goes to the rear brakes since they're the ones we're trying to tune to get them to match what we have up front - whatever those are and the grip we have there.




http://www.wilwood.com/TechTip/TechFaqs.aspx

[dhutton]

I've always bench bled the way Greg described above but apparently there is a new better way to do it with the ports plugged. Tobin from Kore3 and Paul from Hydratech were both talking about it:

http://hydratechbraking.com/braketech1.html

I'm going to give it a shot the next time. A lot of master cylinders are coming with plugs for bench bleeding.

Don

[Vince@Meanstreets]

I've always bench bled the way Greg described above but apparently there is a new better way to do it with the ports plugged. Tobin from Kore3 and Paul from Hydratech were both talking about it:

http://hydratechbraking.com/braketech1.html

I'm going to give it a shot the next time. A lot of master cylinders are coming with plugs for bench bleeding.

Don

I started using that method too since the Wilwood masters come with plugs. Its nice cause can do it on car.

[GregWeld]

Hey! I'm all for learning new tricks! Now I'll research this 'tubeless' bleeding technique too!

[72Z/28]

Now -- here's the problem with buying a "one size fits all" proportioning valve...


Those valves are usually specific for a car - as it left the factory. Well ---- as it left the factory it had bias ply skinny tires.... Now days we have staggered tire sizes... with big fat ones out back and fat nice ones in front...and or we also have different rotors and calipers on than came from the factory.... so now the brake bias is all wrong for what we currently have on the car.

Thus -- most people around here (performance enthusiasts for lack of a better term) will put on an ADJUSTABLE PROPORTIONING VALVE -- which, obviously, can be adjusted so that the bias will be proper for the car it's installed in.

The last thing you want to have happen is for you to need to panic stop, god forbid it's wet out -- and you lock up your rear brakes and have the ass end swap with you. Thus the need for the proper ratio of front braking power to rear braking power AKA a brake proportioning valve.

Wilwood will be happy to sell one to you -- along with a mount (if you want to use theirs) and instructions... The proportioning valve ONLY goes to the rear brakes since they're the ones we're trying to tune to get them to match what we have up front - whatever those are and the grip we have there.




http://www.wilwood.com/TechTip/TechFaqs.aspx

Thanks Greg for the write up. Actually the Wilwood MC was installed by the previous owner and I don't have the bleeding kit. I guess I am going to order the plugs to bleed the MC on the car.

As for the new stock proportioning valve, does that mean that it will not work properly with the wilwood MC and calipers? I wonder if wilwood sells a valve that does not require any adjustments because the car will not be used for autocrossing or at a track.

One more point, I recently replaced the rear brake line from right stuff detailing. It is a 1/4" line, which is basically a stock replacement. However, wilwood recommends a 3/16" line.

[72Z/28]

depends on the type of bleeder system you have. What did you use to bleed the master cylinder?

I have not done yet, but I guess I am going to get the plugs and bleed the MC on the car

[408sbfmustang]

Possible that the metering valve is stuck in it.

[GregWeld]

Thanks Greg for the write up. Actually the Wilwood MC was installed by the previous owner and I don't have the bleeding kit. I guess I am going to order the plugs to bleed the MC on the car.

As for the new stock proportioning valve, does that mean that it will not work properly with the wilwood MC and calipers? I wonder if wilwood sells a valve that does not require any adjustments because the car will not be used for autocrossing or at a track.

One more point, I recently replaced the rear brake line from right stuff detailing. It is a 1/4" line, which is basically a stock replacement. However, wilwood recommends a 3/16" line.




You might have misunderstood why I posted what I did.... In a nutshell -- the stock type prop valves are designed to work with pretty much stock tire and brake sizes... I didn't say it wouldn't work with the master cylinder... I was giving you some information you could use so that you might question the use of a stock prop valve over a adjustable prop valve if you're NOT running stock or nearly stock tires etc. This is a safety issue.... you're brakes and understanding them should be your most important concern. Spinning at freeway speeds is nobodies idea of a good time. The brake bias of your system is critical to work properly when you'll need it the most... a panic stop.

[Vince@Meanstreets]

Possible that the metering valve is stuck in it.

A good bleeding will center it. The first thing I looked for in his first picture was that black rubber nipple. It just sounds like he has a bunch of air in it.

[72Z/28]

You might have misunderstood why I posted what I did.... In a nutshell -- the stock type prop valves are designed to work with pretty much stock tire and brake sizes... I didn't say it wouldn't work with the master cylinder... I was giving you some information you could use so that you might question the use of a stock prop valve over a adjustable prop valve if you're NOT running stock or nearly stock tires etc. This is a safety issue.... you're brakes and understanding them should be your most important concern. Spinning at freeway speeds is nobodies idea of a good time. The brake bias of your system is critical to work properly when you'll need it the most... a panic stop.

You are absolutely right and I am not disagreeing with you Greg. As you said, the tires,wheels, and the brakes are all modified;therefore, the stock valve might not fit this application.

I started looking at the wilwood valve but the I have to order different size MC fittings to install the valve. Unfortunatelly the fittings are in back order and need to wait for two more weeks to get them.

As for the front to rear brake line, i am running stock 1/4 in brake line, which I installed recently but wilwood recommends 3/16 line instead. I am not sure if there is a prebent line in the market

[GregWeld]

As for the front to rear brake line, i am running stock 1/4 in brake line, which I installed recently but wilwood recommends 3/16 line instead. I am not sure if there is a prebent line in the market



Most tube today is 3/16” or ¼”. 3/16” is stiffer, lighter, and easier to bend. It and its associated fittings are also the most common. ¼” has less internal friction (less resistant to fluid flow) and is easier to handle without damaging. Note that ¼” DOES NOT “provide more volume” to actuate the callipers more quickly as I have read more times than I care to remember. The MC piston’s bore and stroke determines the fluid volume displaced and therefore the pedal stroke required to apply the brakes. The tubing is sealed and full – its diameter has nothing to do with it (within reason) and you certainly won’t notice the difference between ¼” and 3/16” – except maybe the placebo effect cuz your buddy said so! I personally like to use 3/16”.

[Sieg]

Chassis line from master to drop down is 1/4" and 3/16" line from the drop down to calipers is OEM spec?

[GregWeld]

Chassis line from master to drop down is 1/4" and 3/16" line from the drop down to calipers is OEM spec?



Some OEM ABS systems combine the use of 1/4 and 3/16" in the same system. I researched this question for a couple hours and could find nothing definitive to explain the "recommendation" of 3/16" over 1/4" in this closed system. The volume difference - even if you calc'd all the line length and diameters is negligible and the PRESSURES would be the same in both line sizes.

[Vince@Meanstreets]

Some OEM ABS systems combine the use of 1/4 and 3/16" in the same system. I researched this question for a couple hours and could find nothing definitive to explain the "recommendation" of 3/16" over 1/4" in this closed system. The volume difference - even if you calc'd all the line length and diameters is negligible and the PRESSURES would be the same in both line sizes.

3/16" tubing is lighter due to material and fluid capacity and easier to package and and form. lighter = faster