Proportioing valve vs residual valve

[RICH MUISE]

Here's a link to a speedway tech article on what we need for our brake systems. Originally posted by Jeff on the 52-59 Ford Hamb social club. Thanks Jeff
https://www.speedwaymotors.com/the-toolbox/residual-vs-proportioning-valves-and-what-your-brake-system-needs/31069?utm_source=marketing&utm_campaign=toolbox022721&utm_medium=email&utm_content=hero

Please note: As stated below by several of our knowledgeable members, this article should be taken with a grain of salt.

[KULTULZ]

Not meaning to start a food fight ... 

I find it poorly written, not researched and offering incorrect advice. I am not hammering you but most of the info online is not correct (IMO)

[RICH MUISE]

Not sure what you could disagree with in the copied paragraphs, other than the "offroad use only" warning is misleading. I took it to mean offroad while the valve is being set properly.. ??
yeah, me too, I hate food fights, lol, but I posted it because of numerous discussions we've had here about both residual valves and adjustable proportioning valves. I didn't read it all, but the description of how to set a proportioning valve is pretty much what I did. If something is not correct, please elaborate so we can correct or delete the article.

[KULTULZ]

Simply put, what they are selling is not a proportioning valve but an adjustable anti-bias valve that is meant for off-road competition cars only. It is not DOT approved.

All tell you to use one to 'balance the vehicle brake bias, but it is simply not possible to do as a street driven car encounters situations where the proper variable pressure design is needed (IMO).

Then the honest ones will have a disclaimer such as the one I showed (WILDWOOD) stating that if used on the street and you bust your rump, it is on you as this warning negates them from liability.



As for the description of the RESIDUAL PRESSURE VALVE(S), they mix #2 and # 10 description and usage together causing confusion among the readers. Their description and use should be separated by system use rather that having their purpose(s) grouped together.

Please leave the post as it is and may help others understand that all of these BRAKE VENDORS and KIT SELLERS have a different song and dance.

[Ford Blue blood]

I'm going to agree with KUTULZ here.  While there was some good info in the article if feel it was rather self serving in nature and contained only partial information.  The factory installed "proportioning valve" in split systems serves more then one purpose.  The "bias adjust valve" serves one purpose and it is set the bias to any given set of circumstances the competition vehicle my be encountering at the moment.  The residual valves have a completely different and unrelated purpose.  Example, the NASCAR guys "dial out" as much rear brake bias as they can to do the burn outs. 

65 Birds were one of the first production vehicles Ford had with front disc brakes.  The system was/is a single fruit jar with a proportioning valve installed in the rear line.  Later autos (I think 67 or 68 MY) were required to the have the split front/rear systems. 

Enter the "proportioning valve".  It can be found on every factory dual system and you see it accompanying many of the disc brake kits.  This "block" does more then split the two systems.  It issues a warning if there is a failure in either the front or rear part of the system.  There is a piston inside the block that will slide and activate a switch to turn on the "brake light" on the dash.  This piston also serves to close of the offending part of the system off to allow the remaining part to do something more then let the pedal go straight to the floor.

Most all of the above was learned by reading, doing and experiencing.  My street rod had the "latest" braking system on it.  Front dics, rear drums, dual master and all new lines.  No valves of any kind.  Two miles from the house, OOPS, pedal goes to the floor, no brakes, what the hey?  I did have a "dual" system?  Rear flex line failed.  Looked at cars in the junk yard.  Saw the block, figured if the factory put it there it must be for a reason.  Read a bunch (way before the internet), found out the true reason for it's existence.  Mind you, now they have gotten much more complex and require a computer to set "bias" and control the amount of braking.

So I say when building a car of any kind follow the factory lead, keep as many components as possible from the same donor and live happily ever after with a trouble free brake system.

[59meteor]

In my experience, as a auto mechanic for over 40 years, most of that at the dealership level, I have to say that although the factory proportioning valve function as a safety device seems effective on paper, much like "self adjusting" drum brakes, it seems to not work as well in the real world. Over the years, I have experienced numerous cases, where either a brake flex hose failed, or a steel brake line rusted out, and in each case, the brake pedal went right to the floor, without a hint of the supposed built in "back up" braking from the valve closing off the leaking side. On Toyota 4 Runners, it was fairly common for the rear steel brake lines above the rear axle to rust thru, from mud getting built up on a crossmember, coving the steel tubing. I repaired dozens of these vehicles, that were towed in, and I would slowly, and carefully drive them into my bay, using the park brake, as the brake pedal sunk all the way to the floor, with zero braking available. Yes, the brake warning light in the dash came on, so obviously the internal valve did move, but it did not "seal off" the rear brake port. I had a buddy with a late 70s F350, which on occasion, would spread the front caliper bracket enough that the caliper could come loose. He was hauling his drag car down a hill, and when he hit the brakes to scrub off some speed, he said there was a loud clunk, and the brake pedal went straight to the floor. His RF caliper came out of the saddle, ripped off the rubber flex hose, and no brake function at all. Luckily, between light traffic, a manual transmission, and the parking brake, he was able to get the truck stopped without hitting anything. If you think about it, if the proportioning valve work as the theory behind it, it would be very difficult to bleed the brake system. Has anybody not noticed when helping somebody bleed the brakes, that once the bleeder is opened, the pedal goes right to the floor? If the valve truly did close off one side, that would not happen.

[RICH MUISE]

I thought about deleting the link to that article, but I did not want to delete the points brought up, so I added a note of caution to my original post. Thanks for your input guys.

[KULTULZ]

... although the factory proportioning valve function as a safety device seems effective on paper, much like "self adjusting" drum brakes, it seems to not work as well in the real world.

The valve actually being discussed is the Pressure Differential Valve (PDV), not the PROPORTIONING VALVE (PPV). It's purpose is to allow a pintle to move to either side to trip the BRAKE WARNING LAMP to indicate a service failure. It is not designed to stop flow between the two circuits (although GM had one that would).

It would depend on the type and severity of the failure. It's design was to allow the vehicle to hopefully make a safe stop on just one circuit, not to continue driving.

[KULTULZ]

I thought about deleting the link to that article, but I did not want to delete the points brought up, so I added a note of caution to my original post.

Thanks for your input guys.

And I THANK YOU as this may finally bring to light the inaccuracies between all the vendors.

[SkylinerRon]

That warning label is a basic "cover your butt" statement. The second sentence is saying that their valve is not a replacement for any OEM valve. This is for anyone who would attempt to use their valve as a PDV or PPV.

Since no OEM uses a owner/driver adjustable valve it is left to folks who know what they doing to fine tune their brake balance.

Ron.

[1930artdeco]

So if I understand this thread correctly, the proportioning valve doesn't really work? I see the adjustable ones working for race applications only. I understand the theory-which is why I ordered one along with a new Master from a 69 mustang-all OEM styles. So should I not bother with the one I bought?

Mike

[SkylinerRon]

Need more info.  Are you using Mustang brakes on a 1957?

Example, I converted a Fox body to 4 wheel discs and the adjustable valve modulates the rear brakes so they don't lockup before the front brakes do.

Good luck,

Ron.

[RICH MUISE]

I installed the proportioning valve (Wilwood) when I first got the car on the road with drums still in the rear. Definetly needed it because the drums in the back would lock up before the front discs until I got the valve adjusted correctly.

[1930artdeco]

Ron, using stock brakes just wanted a dual master for safety reasons. I was going to install a 69 mustang manual drum/drum MC. But, the parts guy could not find a valve to match. Not sure there is one until discs came out. Just trying to understand how things work.

Mike

[KULTULZ]

Ron, using stock brakes just wanted a dual master for safety reasons. I was going to install a 69 mustang manual drum/drum MC. But, the parts guy could not find a valve to match. Not sure there is one until discs came out. Just trying to understand how things work.

Mike

There is no PPV on a drum/drum system as the brake end sizing is formulated to bring the car down somewhat safely (although GM used it on some LT applications).

The reason for the PPV on DISC/DRUM installs is to slow down the rear drum application as they are self energizing, i.e. they usually become active/more aggressive before the front disc with pedal application. A METERING VALVE is used on the front disc to slow down front brake application until the rear shoes (w/ functioning self-adjusters hopefully) become fully engaged. The PPV has a variable application pressure(s) as brake line pressure increases/decreases. A ANTI-BIAS valve has a set pressure. It is adjustable only when the control valve is plumbed where the driver can operate it by hand. The 'DIALING-FOR-DOLLARS' spin the wheel variety is for drag cars, not road cars. Most find it difficult to reach out and adjust it while the car is moving.