i always run my lines from the master to the dist block, then plumb the prop valve into the line running from the dist block to the rear brakes.

6sally6 wrote:

Does the proportioning valve which is plumed in after the MC.........do the lines go from there to the brakes or........do they need to go back through the distribution valve that came on the 66?
thanx
6sally6

Mike,  IIRC you are switching from 4 wheel drum to a disc drum dual bowl power booster scarebird setup right?

If you are referring to the brass distribution block, the stock setup for that was that the MC went to that brass block and then 2 lines out to the front brakes and 1 line out rear brake lines. a total of 4 lines on that brass thing.   Leave the front brake lines connected to the brass thing, and remove the rear brake line from the brass thing. Also remove the mc line from the brass thing.  

  with a dual bowl disc drum mc, the larger bowl should be for the discs, and a new line would go from mc to the brass distribution block, and then out to the front brakes. you will need to plug up the extra hole on the brass block with an ?asn inverterted flare? plug, since you removed the line to the rear brakes.   I dont think i'm giving it the correct name..  Anyway from the smaller bowl of the mc, a new line woud go to a seperate adjustable rear prop valve which has two ports labeled IN and OUT.  connect MC to IN, and then OUT to the unhooked rear brake line that was taken off the brass distribution block. 

This above paragraph is one way to do it.    There is another option to get rid of the brass block and the adjustable proportioning valve by getting another single fixture that will take the place of the two separate pieces. I'm pretty sure MS has a FAQ for this.   I think the popular way is to get a fox combo valve which will handle both functions (distribution and Proportioning) in one piece as well as an added benefit of a third function of Metering.  this would require some creativity to creating the new lines from MC to this combo valve and then to connect it to the rear brake line and the front brake lines.  they do sell kits that have the valve and the lines already pre bent for you.

IIRC there are a few things to consider when deciding on which to choose..  Distribution, Proportioning, and Metering.  Distributing the fluid to the front and rear brakes, Proportioning the pressure so that rear brakes get applied first but dont lock up before front brakes are applied, and Metering which eludes me at the moment... I dont recall if it meteres uneven pressure between front and rear and compensates, or somehow meters it to throw a warning light on dash in case of a leak or a low fluid condition?

Also when creating the lines, the loops of the lines are not to be higher than the mc. 

Sal, you are using the 70 style combination valve.  Plumb it exactly like the diagram on my GRANADA brake installation page.  DO NOT reuse the existing distribution block.  I supplied the 7/16-24 tube nuts for the fittings requiring those.  The 3/8" tube nuts will come with whatever tubing you buy.

Hey MS and Moderators, why not start a new heading in the index for "Sticky"  or other saved high-info threads??
This is a good example of one.

Corky

The valve pictured on my post is correct.  It denotes which port on the master cylinder connects to that particular port.  The others show whcih brake, front or rear, that feeds that port.  Rather than leave room for confusion, I try to tell them which actual port on the master cylinder feeds that line.  Alot of people do not realize the rear port on the mc feeds front brakes and front port feeds rear brakes.  I think even my picture can stand to have some clarification, to make it totally clear.

These posts are a very good example of WHY someone posting a question should explain the details about what they are talking about.  The various replies assumed he had a drum brake single pot master cylinder, a disc brake GT single pot master cylinder, a tandem master cylinder, an adjustable proportioning valve, a drum brake distribution block, a disc brake distribution block, etc etc.  Everyone was trying to guess what the question really was because NO info was provided as to what was being installed.  One would have to have been following 6sally6's previous posts very carefully to understand what he was working on.  I had some inside information because I sold him the combination valve in the picture, and he had told me he had ordered a Maverick master cylinder, plus I had read the posts about the scarebird disc brake conversion.  Not to pick on sal, but this is just a good example of how making the question as clear as possible will save everyone a lot of typing and most likely get better responses and a more accurate answer.  OK, so much for the "MS SATURDAY SOAPBOX"

ultrastang wrote:

The labeling on the valve diagram says," Inlet (from M/C front)."  If you interpret that to mean that you connect the Front Port of the MC to that port location on the valve, then you have just connected the part of the MC that's supposed to supply brake fluid to the REAR brakes.

The" Inlet (from M/C front)" means the line from the MC that supplies fluid to the front brakes should be connected to that location on the valve, not that the (physical) front port of the MC connects there. The (physical) rear port of the MC would be the port that connects to the "Inlet (from M/C front)."

This is all 6sally6's fault,  LOL.   sorry to post that I was confused about MS and Ultrastang diagrams, but If i was confused I'm sure others were confused as well if they were actually paying attention to labeling of both of the diagrams. ANd when it comes to brakes, I'd rather get it clarified than to just let it go. Not trying to put out a fire with gasoline here... 

EVEN though Ultrastang and MS were referring to the same thing in thier diagrams, both of your diagrams were confusing to a novice reader.  MS diagram was referring to  FRONT as a physical port on the MC.   Ultrastangs diagram was referring to FRONT  as the actual BRAKE SYSTEM BOWL on the mc which is physically the rear port.  Clarification was needed.  ANd you both were correct depending on how  you read them.  But I have no idea from those diagrams what you both had in mind when labeling FRONT on the inlet.

  I made the assumption in my previous post that he originally had a drum drum single bowl mc setup which only has 1 line on it going to the T brass distribution block.  Ultrastang made the assumption that he originally had a disc drum single bowl "GT" mc brake setup which has 2 lines on it going to the T Brass distribution block and the Kelsy hayes prop valve, and ultra gave instructions based on that.  I'm really not sure if a disc/drum mc single bowl was specifically a GT thing or not.  Maybe non GT cars had the disc/drum option.  I don't know the answer to that.  Point is that we both gave different plumbing instructions based on our assumptions.  

  sometimes it takes a person like me who is reading the replies as an novice and not as an expert, to question the expert replies that you both have given whenever its not clear or it appears to conflict with each other or from what I have read elsewhere.  

I'm just trying to clear this all up for anyone else who reads this thread and reads my post and understands that my previous post is just for a drum drum setup and does not apply to those of you that originally have the GT or disc drum mc and are converting to front disc brakes with a dual bowl mc. My reply was specific to 6sally6 only and not to be taken as a RULE when doing your own disc brake  or power disc brake conversion.    As tubo states maybe a whole new thread or STICKY should be made on all the different OE stock configurations that existed before doing any kind of disc brake conversion,   so that all the different type of plumbing configurations are explained ONCE and for all.

MustangSteve wrote:

I Think BOTH of our diagrams could have a better description as to where those lines come from.  What it really needs is a picture of the MC right next to it to remove all doubt.

About 4 months ago, a guy from another forum posted this photo.



I immediately noticed something seemed wrong but couldn't be positve without seeing the other side of the MC to know where the lines were actually connected. I made a post that it looked like the lines were swapped on the MC. The guy got miffed at me for having the audacity to question his handy work. In an effort to "fix my wagon," he posted this picture to prove to me that I was wrong and that he didn't get it backwards.



After he posted this picture, it was no longer a matter of my suspicion that he plumbed it wrong. It was completely without a doubt, at that point, that he plumbed it wrong!

...Sooo, I took his own photo and labelled the ports with which port feeds which brake circuit and then posted this.




I took this picture from my shop manual and imposed an "F" and "R" (and what they equalled) so that he (and anyone/everyone else) would know that the (physical) front port of the MC does NOT go to the front circuit of the valve ("front" being the end of the valve that has (3) ports on it).



If you are doing brake work --such as changing MCs, doing a brake conversion or whatever, think of the above picture as if you are on Google Maps where "F" is the starting point of your destination. As long as you remember that the (physical) rear port of the MC is the feed to the front brakes and that the line from it goes to the end of the valve that has (3) ports, everything else will take care of itself.

 

Last edited by ultrastang (5/26/2013 12:12 PM)

steve s. wrote:

MarkinSC wrote:

steve s. wrote:

i always run my lines from the master to the dist block, then plumb the prop valve into the line running from the dist block to the rear brakes.

I don't see how that is possible if you have a dual bowl mc.  The stock single bowl master had 1 line to the brass block.  A drum/drum dual bowl would have two lines coming out correct?  A disc/drum would also have two lines coming out.

i did like the others, i "assumed" :-)...   

my thinking was that "if" he was adding a stand alone prop valve for the rear, he was upgrading the brakes to a dual master & discs all the way around.

another thing that gets confusing is the use of the term "distribution block" & "proportioning valve/combination valve". in the hot rodding circles i grew up in, a distribution block is just that, a glorified "T", where the prop/combo valve has the "valve" part inside to regulate the rear brakes. take the valving out of a combination valve & its then a distribution block.
 

Prior to 1967, a Mustang brake system would have had a simple Tee (or manifold block) that the lines connected to. It would have had no internal mechanical functions. Beginning in 1967, government regulations required auto manufacturers to install split brake systems (dual reservoir MCs).

If the vehicle had drums all the way around (on a '67-later vehicle) then the MC would have connected to a pressure differential valve, or sometimes called a 'distribution valve.' This valve body has a spool inside that senses if there is a pressure drop (differential) between the front vs. rear brake circuits. If there is a drop in fluid pressure the spool shifts to the low pressure (failed) side to close that circuit off so that brake fluid isn't pumped out onto the ground, --which would empty the MC if there was no device to cut the fluid flow off.

If the vehicle had discs on the front and drums on the rear, then the MC (on a '67-later vehicle) would have connected to a combination valve --which is commonly called a 'proportioning valve' but proportioning is only ONE feature of what a combination valve does.

The disc/drum combination valve contains a pressure differential valve (just like the drum/drum valve), to warn of a pressure loss (brake failure). It also has a metering valve to momentarily hold off fluid to the front discs to give the rear drums time to overcome the tension of the retracting springs. The final feature of the combination valve is the proportioning of fluid to the rear drums. 

So, in relation to 1967 and later Mustangs/Fords, a drum/drum pressure differential valve has only the one function of sensing a pressure drop and triggering the brake warning light on the dash. A disc/drum combination valve performs three functions; sensing for a pressure differential to warn of a brake circuit failure, the metering of fluid to the front discs and the proportioning of fluid to the rear drums.
 

Last edited by ultrastang (5/26/2013 8:12 PM)

MustangSteve wrote:

OK,now that we have all THAT straightened out...

GOT IT, Sal?

This can be VERY (mentally) tiring trying to explain all the brake configuration possiblities on Mustangs/Fords, and would be even harder to try and explain it with just text and no photos. It gets even more complicated trying to explain it when someone is going from a pre-'67 era brake system to needing brake components from a '67-up era and what parts need to be eliminated and what parts need to be added, to make the system work safely and correctly.

...I think I'm gonna let my brain rest now. 

Last edited by ultrastang (5/26/2013 8:15 PM)

Good idea, Mark.  Take pictures off all those configurations and I will label them and put them on the website.

Let the leverage of the brake pedal seat that rod once you get everything bled.  That way the MC is held in place by the flanges and not in a vise where it might get distorted.