Proportioning valve

[Big Slim]

i am working on brake upgrade and looking at the proportioning valve selection. i was wondering if i used the willwood combo valve that has a sensor on it, can this sensor be used for the warning light and then be able to remove the h-block? if not, or need to keep the h block, then ill probably get the single knob style.

 

[Steve83]

Adding a proportioning valve is NOT an upgrade; it's just an expensive complication. You'd have to read what Wilwood designed that sensor to do.

 

[Big Slim]

well the upgrade is hydroboost, not the valve. that is what is missing from previous owner work on the 4 wheel disc conversion.

 

[Big Slim]

dang. it was right there in the PDF. the sensor is a brake light pressure switch not warning light.

 

[Steve83]

A proportioning valve is not a requirement for hydroboost or disk brakes. Ford never used one on vehicles designed with those systems.

 

[jamesroney]

A proportioning valve is not a requirement for hydroboost or disk brakes. Ford never used one on vehicles designed with those systems.

Bold statement. Totally factual, but you are going to confuse the huddled masses.

The "thing" that connects to the master cylinder in modern disc brake automobiles (after about 1971...) should be called a combination valve. The combination valve performs up to 4 basic functions when used with disc/drum applications.
1. It CAN provide front to rear brake bias, (proportioning valve or metering valve)
2. It CAN provide delayed application to the front hydraulic circuit. (delay valve)
3. It provides a hydraulic failure warning circuit shuttle valve.
4. It provides a distribution junction point for convenient plumbing.

Unfortunately, the combination valve has been named the "proportioning valve" whether it provides any proportioning or not. This mis-nomer causes great confusion and has resulted in the sale of countless un-needed brake hydraulic components.

A properly sized and engineered disc/disc system does not require metering, biasing, or delay. So the 5 port "proportioning valve" is just acting like an expensive h-block.
An improperly sized disc/disc system needs metering. This can be done with a 5 port proportioning valve, or with a discrete valve in the rear line.
All disc/drum combination systems need a delay valve to prevent front wheel lockup on panic application.

@Big Slim I hope that helps.

 

[Apogee]

My '77 EB came with front disc brakes and a proportioning valve, so I'm not sure what Steve83 is talking about, but what a proportioning valve can do for you is allow for more rear brake at lower deceleration rates while preventing premature rear brake lockup at higher deceleration rates. Short wheelbase rigs with higher CoG's can definitely benefit from that IMHO, as do others.

As for the Wilwood distribution block with built-in adjustable proportioning valve (260-11179), it does come with a pressure switch, however I never use it and I recommend that most of my customers not use it either. While it can be a convenient way to trigger the brake lights in a hot rod application with custom pedals/dash/etc, you can't really beat the function and reliability of the standard electro/mechanical limit switches commonly used at the pedal. I've had a few instances where the hysteresis of the pressure switch caused the brakes lights to remain on and killed the battery, so we just remove the switch and install an 1/8-27 NPT flush plug in it's place to clean things up a bit.

For the brake warning light, you can either run an OE-style (GM or Ford) combination valve with the brake pressure balance switch in the center, or an H-block with the same feature, as either will control the brake warning light on the dash as intended.

Tobin

 

[Timmy390]

Been running the stock manual brake H block for years with power drums and disc. No issues as of yet

Hydroboost increases pressures? That's a question cause I don't know. If so maybe you run the risk of blowing it out?

Tim

 

[Big Slim]

my disk/disk is the K5 fronts and eldorado rears. the hydroboost is from astro and the MC is dodge. i would not believe that this combo is a perfect setup so thats why i was going to put in the proportioning valve for the rear. ill leave the H-block since it has the warning light attached. i will need to get one of those tools so i can bleed it.

 

[Steve83]

All disc/drum combination systems need a delay valve to prevent rear wheel lockup on panic application.

Ford never used a delay valve in '80-96 F-series/Broncos with disk/drum brakes. Not in the early non-ABS systems; not in the 1-channel RABS systems; not in the '93-96 Bronco 3-channel 4WABS systems. '87-96s all have a residual pressure valve for the rears, which is nearly the opposite of a delay valve.

 

[jamesroney]

my disk/disk is the K5 fronts and eldorado rears. the hydroboost is from astro and the MC is dodge. i would not believe that this combo is a perfect setup so thats why i was going to put in the proportioning valve for the rear. ill leave the H-block since it has the warning light attached. i will need to get one of those tools so i can bleed it.

So here we go again with "lingo." When you say El Dorado rears, do you mean the 76-78 El Dorado with the 2.5 inch bore, or the 79-85 El Dorado with the 2-1/8 bore? The K5 caliper has a 3 inch bore. So the piston area is 7.065 square inches. The 79 El Dorado caliper has a piston area of 3.544 for a ratio of 1.99.

For calibration, the ford explorer uses a front caliper diameter of 1-13/16 (x2) or 5.157 sq in, and rear piston of 1-7/8 or 2.76 sq in for a ratio of 1.86. The 03-06 Jeep wrangler rubicon runs a 66mm (2.598) inch front caliper, and a 1-7/8 rear for a ratio of 5.299/2.760=1.92

This is why the explorer disc set up works so well on a Bronco. With K5 fronts and explorer rears, most all the braking goes to the front.

 

[toddz69]

my disk/disk is the K5 fronts and eldorado rears. the hydroboost is from astro and the MC is dodge. i would not believe that this combo is a perfect setup so thats why i was going to put in the proportioning valve for the rear. ill leave the H-block since it has the warning light attached. i will need to get one of those tools so i can bleed it.

Good choice. You'll find that the Eldorado calipers are really too big from a balance standpoint on our trucks so a proportioning valve is needed.

Todd Z.

 

[jamesroney]

Ford never used a delay valve in '80-96 F-series/Broncos with disk/drum brakes. Not in the early non-ABS systems; not in the 1-channel RABS systems; not in the '93-96 Bronco 3-channel 4WABS systems. '87-96s all have a residual pressure valve for the rears, which is nearly the opposite of a delay valve.

Of course you are right. Thanks. And yeah...I need to be more careful typing "rear" when I mean "front." I'll fix my post.

The delay valve, or hold off valve is located in the Front Disc Brake side, and delays the FRONT wheels from locking in a panic stop. The rear wheel cylinders need some fluid movement to expand the shoes...so the hold off valve is located in the front circuit. I'm not saying that the 80-96 F series doesn't have a hold off valve...but I THINK it is in there.

 

[stupidboy]

Nice information jamesroney

 

[toddz69]

So here we go again with "lingo." When you say El Dorado rears, do you mean the 76-78 El Dorado with the 2.5 inch bore, or the 79-85 El Dorado with the 2-1/8 bore? The K5 caliper has a 3 inch bore. So the piston area is 7.065 square inches. The 79 El Dorado caliper has a piston area of 3.544 for a ratio of 1.99.

For calibration, the ford explorer uses a front caliper diameter of 1-13/16 (x2) or 5.157 sq in, and rear piston of 1-7/8 or 2.76 sq in for a ratio of 1.86. The 03-06 Jeep wrangler rubicon runs a 3 inch front caliper, and a 1-7/8 rear for a ratio of 7.065/2.760=2.56

This is why the explorer disc set up works so well on a Bronco. With K5 fronts and explorer rears, it is exactly the same as an 03 Jeep Wrangler.

With K5 fronts and 79 El Dorado rears, (and assuming a LOT) you will need to cut the rear brake pressure by about 28%.

I always *assume* (and yeah, I know that's bad) that folks are assuming to the 79-85 El Dorado calipers when they say that since 98% of people don't even know the larger, earlier ones exist and I'm not sure there's even a kit available for for those calipers for the 9"?

Did the Rubicon use a larger front caliper than the regular TJs of that era? I was doing some brake balance math a few weeks ago and looked up the Jeep stuff and it said 66mm (2.60"), which pencils out to 5.31 sq. in."

I also looked at the D90s as a possible corollary for brake balance and the current setup on my truck was within 1% of those rigs in terms of f/r balance so I figured I was pretty good.

Todd Z.

 

[jamesroney]

I always *assume* (and yeah, I know that's bad) that folks are assuming to the 79-85 El Dorado calipers when they say that since 98% of people don't even know the larger, earlier ones exist and I'm not sure there's even a kit available for for those calipers for the 9"?

Did the Rubicon use a larger front caliper than the regular TJs of that era? I was doing some brake balance math a few weeks ago and looked up the Jeep stuff and it said 66mm (2.60"), which pencils out to 5.31 sq. in."

I also looked at the D90s as a possible corollary for brake balance and the current setup on my truck was within 1% of those rigs in terms of f/r balance so I figured I was pretty good.

Todd Z.

No, it's the same 66mm front caliper for all of the TJ's. I just can't do math on my iphone calculator, and somehow converted 66mm to 3 inches. I was doing the explorer caliper math, and it has two pistons, and then I was doing K5 lookup while talking on speaker phone about ash tray brackets. So you are right, and I'll go fix my post. Thanks!

 

[Big Slim]

so a combo valve unit for disk/disk would be a better option than proportioning valve to rear and stock h-block? is there any adjustablility to these or good out of the box?

 

[jamesroney]

so a combo valve unit for disk/disk would be a better option than proportioning valve to rear and stock h-block? is there any adjustablility to these or good out of the box?

If you are disc/disc...then an H-block with an adjustable prop valve in the rear is the way to go. You don't need any of the other features of a combo valve if you are running disc/disc. It's the mismatch in pressure and movement and time between discs and drums that require all of the hydraulic valving.

 

[Big Slim]

perfect. that will be the plan then.

 

[ba123]

I have at least 1, maybe 2 of these for sale if interested in a prop valve. (I have 2, but def don't need 2)

Brand new, just been sitting in package.

$40 + shipping cost.