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Adjustable proportioning valve for disc brake swapped 14FF questions.

handloader90

handloader90

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Got a 14FF that I did disc brakes on I believe this past winter.

Wanna put it under the truck. I know about the nice Wilwood unit that has been mentioned around here before which pretty much replaces the stocl unit, all of the brake lines are ran through that specifice Wilwood unit.

Link to said valve: https://m.summitracing.com/parts/wil-260-11179/overview/

My question is can I splice a unit in on just the rear hard line and use it in conjunction with the stock prop valve?

Something like this: http://www.jegs.com/i/JEGS/555/6302...8QshwUJNZjWMSJgFKYG2zLVPXsdmG4n9cwaAtbB8P8HAQ

From what I've read the stock disc/drum prop valve pushes way more pressure to the rear due to the wheel cylinders in the disc brakes needing them.

Problem with disc/drum prop valve with a disc/disc setup seems to be the rear brakes locking up before the front.

Seems like throwing a prop valv in just the rear line and turning it down would get rid of this problem. Does this seem right or is the stock prop valve gonna cause issues with a setup like this?
 
handloader90 said:
Got a 14FF that I did disc brakes on I believe this past winter.

Wanna put it under the truck. I know about the nice Wilwood unit that has been mentioned around here before which pretty much replaces the stocl unit, all of the brake lines are ran through that specifice Wilwood unit.

Link to said valve: https://m.summitracing.com/parts/wil-260-11179/overview/

My question is can I splice a unit in on just the rear hard line and use it in conjunction with the stock prop valve?

Something like this: http://www.jegs.com/i/JEGS/555/6302...8QshwUJNZjWMSJgFKYG2zLVPXsdmG4n9cwaAtbB8P8HAQ

From what I've read the stock disc/drum prop valve pushes way more pressure to the rear due to the wheel cylinders in the disc brakes needing them.

Problem with disc/drum prop valve with a disc/disc setup seems to be the rear brakes locking up before the front.

Seems like throwing a prop valv in just the rear line and turning it down would get rid of this problem. Does this seem right or is the stock prop valve gonna cause issues with a setup like this?
Click to expand...

IIRC, the stock combination valve is also maintaining some residual pressure so the rear brakes won't fully release. This is to balance out the springs in the drum setup, but a disc setup doesn't usually have such. So you could set your proportioning, but you'd still have dragging brakes.

This is theory, I haven't done this swap.
 
I just saw a recent thread in the garage where I giy mentioned the pads on his disc swapped 14FF were prematurely worn... like pretty bad.

The othet CK5ers mentioned the residual valve and there was some tech in there about pressures and such.

I guess I'll pony up and get the Wilwood unit that replaces the stock PV and do it right.
 
Here's what I did and I know a couple others have done the same. I gutted all the workings from my stock combo valve basically leaving just the warning system. A couple others have just taken the whole thing out of the system. Originally I had 3/4 ton front brakes that were JB7. Those are the large piston calipers. The rear is 3/4 ton rotors with light 3/4 ton or stock 1/2 ton calipers that are JB6. Now I have the same rears and D60 one ton fronts. In both cases the brakes work great with no proportioning valve. Lock up seems very close on both ends. You may try it without that high dollar valve and see. You can always add it later.
 
I have D60 fronts and 3/4t rears.
I got rid of the stock combo valve and put a Jegs adjustable in line to the rear...adjusted it initially and it works great.
KISS!
 
76zimmer said:
I have D60 fronts and 3/4t rears.
I got rid of the stock combo valve and put a Jegs adjustable in line to the rear...adjusted it initially and it works great.
KISS!
Click to expand...

Interested in this.

Here's what I got, kinda weird setup but It's not permanent.

6 lug dana 44 front, 1/2 ton brakes.
14FF disc swapped with 3/4t rotors and 1/2 ton calipers.

I know you're supposed to have larger brakes in the front but this is whar I have for now... need to get the axle under for a cross country tow (current axle is shady...)

Got a D60 in the garage but I need to redo kingpins, brakes and some other stuff, don't have the timeor money to fool with it right now. It will be going under the truckin a few months.

Remove the stock combo/prop valve then:

Run a single line down from the master cylinder then "T" it off, one hard line from the "T" to each front rubber brake line?

Then a single line from the MC going to the rear with the adjustable prop valve spliced in before the rubber line?

Is it that simple?
 
Yup, it's that simple. Just remember, front line off master is rear brakes and rear line off master is front brakes.
 
AV8TER said:
Yup, it's that simple. Just remember, front line off master is rear brakes and rear line off master is front brakes.
Click to expand...
Hell yeah! Gonna be doing some brakes soon.

And thanks for the tip! I woulda went into it thinking the opposite...
 
Got rid of stock pro valve, lines are completely separate front and rear. Adjustable proportioning valve and residual pressure valve in rear line. Proportioning valve almost closed to rear. Did multiple skid tests at 30 mph with a spotter to watch when rear was locking up compared to front. Only did a couple spins while testing. Got some weird looks while testing.
 
I have 8 lug 10 bolt up front with 3/4 ton calipers. 14 BFF rear with disc conversion and 1/2 ton calipers. I swapped stock MC to a larger disc/disc hydro boost one for an '83 P30 step van(I already have hydro boost). I swapped factory prop valve for a disc/disc one from Summit racing. I have really good brakes and can lock all four up really well and have a good hard pedal feel for what I like. Problem is rears lock up before fronts still and it's real scary on icy/snowy roads(rear passes front and you go round in circles into the ditch). The way the ports were on my MC the rear was in the rear port so I first tried swapping them with some adapters and that didn't change how they worked. I then added an adjustable prop valve from Jeg's, All the way closed is 10 turns out and I had to go to 8 turns out to get the rears to almost not lock up before the front on ice. My old mud terrains don't help with traction. Now that it is nice out I went to 6 turns out to get some more rear braking. Might be a little scary in a panic stop in the rain but I just drive accordingly.
kimg0574-jpg.222907
 
Truckman4life said:
I have 8 lug 10 bolt up front with 3/4 ton calipers. 14 BFF rear with disc conversion and 1/2 ton calipers. I swapped stock MC to a larger disc/disc hydro boost one for an '83 P30 step van(I already have hydro boost). I swapped factory prop valve for a disc/disc one from Summit racing. I have really good brakes and can lock all four up really well and have a good hard pedal feel for what I like. Problem is rears lock up before fronts still and it's real scary on icy/snowy roads(rear passes front and you go round in circles into the ditch). The way the ports were on my MC the rear was in the rear port so I first tried swapping them with some adapters and that didn't change how they worked. I then added an adjustable prop valve from Jeg's, All the way closed is 10 turns out and I had to go to 8 turns out to get the rears to almost not lock up before the front on ice. My old mud terrains don't help with traction. Now that it is nice out I went to 6 turns out to get some more rear braking. Might be a little scary in a panic stop in the rain but I just drive accordingly.
kimg0574-jpg.222907
Click to expand...

I assume you bypassed the combo valve?
 
Truckman4life said:
I have 8 lug 10 bolt up front with 3/4 ton calipers. 14 BFF rear with disc conversion and 1/2 ton calipers. I swapped stock MC to a larger disc/disc hydro boost one for an '83 P30 step van(I already have hydro boost). I swapped factory prop valve for a disc/disc one from Summit racing. I have really good brakes and can lock all four up really well and have a good hard pedal feel for what I like. Problem is rears lock up before fronts still and it's real scary on icy/snowy roads(rear passes front and you go round in circles into the ditch). The way the ports were on my MC the rear was in the rear port so I first tried swapping them with some adapters and that didn't change how they worked. I then added an adjustable prop valve from Jeg's, All the way closed is 10 turns out and I had to go to 8 turns out to get the rears to almost not lock up before the front on ice. My old mud terrains don't help with traction. Now that it is nice out I went to 6 turns out to get some more rear braking. Might be a little scary in a panic stop in the rain but I just drive accordingly.
kimg0574-jpg.222907
Click to expand...

I just ordered that same exact prop valve this morning.

I was planning on bolting mine inside the frame rail under the bed via the two through holes in the prop valve.
 
do it up in the engine bay . high / dry / safe / easy to get to with hood open .

when i did one years ago i whipped up a bracket to bolt to 1 master to booster stud and then adj valve to it with short line from master to valve like he did in his pic.
 
handloader90 said:
I just ordered that same exact prop valve this morning.

I was planning on bolting mine inside the frame rail under the bed via the two through holes in the prop valve.
Click to expand...
Works good. I also had to buy a flaring tool to splice it in. I was going to do a bracket and have it a little nicer but it was below freezing and I was working outside in the winter cuz my main vehicles were both down so I was kinda in a hurry.
 
When I get it all done up I'll put some pics in this thread.

I'll try and make a little mounting plate and put the prop valve near the M/C as suggested.
 
Since we are on the topic of brake plumbing....what size are the brake lines for front and rear?
 
I looked at the lines running out of my M/C earlier.

Rear looks like 1/4" line

Front looks like 3/16" line

Not 100% certain though.
 
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