Disc Brake Swap.. Prop Valve

Suspension, steering, brakes, wheels & tires

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ultraranger
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Re: Disc Brake Swap.. Prop Valve

Post by ultraranger »

michael69 wrote:That's the problem they swapped to disk and kept the drum distribution block. To each their own,but there is a reason why all car makers put a proportion valve on disk brakes. I would rather have it and not need it and not have it in an emergency stop. Ultra Ranger you post as I was typing. I was just letting flyboy know they was not using one with disk.
Agreed. You can dance all you want but sooner or later you have to pay the band. Ford (and any other auto manufacturer) doesn't spend huge sums of money to pay engineers to come up with stuff that doesn't have good cause to be install on a vehicle they are trying to sell. The brakes are the most important component on a vehicle. Going fast is fun but all the go fast in the world isn't worth anything if you cannot stop the vehicle --or more imporatantly, keeping it in control when stopping.

Drums are self-energizing, discs are not. If you have all-wheel drums, then they are reacting much the same in relation to each other. When you combine discs with drums, now things change. Without proportioning & metering functions (like, deleting the valve block altogether) you are allowing the rear brakes to go unchecked in relation to the pressure rise compared to the discs on the front. In an average stop, the front brakes carry 60% of the braking load. In a panic stop, the weight of the vehicle can shift 10% or more. This sudden weight shift now places 70%, or more, of the load on the front brakes. Without any means of regulating the brake pressure to the rear brakes, the pressure applied to the front brakes will be near equal to the rears (without a valve). This linear pressure rise/spike will cause the rear brakes to lock and suddenly the rear of the vehicle will now try to become the front of the vehicle (spin out).

Throwing brake components together without any idea how they work in relation to each other, or worse, not using a valve at all is a recipe for imminent disaster.
Steve

1969 SWB F100 Ranger. 240-6, C-4, 9" N-case 31-spline Traction-Lok w/3.50 gears.

1968 Mustang. My high school car. Owned since 1982.

2003 Azure Blue Mustang Mach1.
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michael69
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Re: Disc Brake Swap.. Prop Valve

Post by michael69 »

Thank you Ultra I just did not know how to explain it well enough to give a specific description. That is why I just said you can't tell a difference unless it is a good speed panic stop. No matter what, people will still say it does not make a difference in their braking. Look at it this way if it did not make a difference in your braking why go though the trouble to swap to disk :hmm:
Michael69

'69 Ranger 'F-100 2WD SWB 351W C6 AUTO
1985 CJ 7 jeep w/35s
1967 SS Chevelle 502 4 speed
2003 Heritage softail w/110 cubic inch screamin eagle kit
mrsnicks
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Re: Disc Brake Swap.. Prop Valve

Post by mrsnicks »

michael69 wrote: Look at it this way if it did not make a difference in your braking why go though the trouble to swap to disk :hmm:
Because all the cool kids are doing it? 8)

Patrick
Chevrolet
Can Hear Every Valve Rattle on Long Extended Trips

1969 F100 4X4 Highboy 390 3sp
1969 F100 SWB 2wd Auto 351w
1972 F100 Ranger XLT 302 Auto

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Whateverman
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Re: Disc Brake Swap.. Prop Valve

Post by Whateverman »

:2cents: I never said it was the right way,just that its the way i did it.
I honestly would advise others to do it "properly" i've been meaning to put the a prop valve in there for years now,however I've done lots of panic stops - guess what? The truck stops better with discs than it ever did with the drums,yeah it skids sometimes during really heavy braking ,but it did that anyways...come to think of it so has every truck i've ever driven ....at least with discs the brakes don't get hot and disappear at the worst possible moment --that my friends is NOT fun at all
- still got my first first car 20+yrs later : 69 f100 sorta kinda pretending its a Mercury M100 w/a 70 f350 sport custom cab (factory buckets) 67 grille with 69 ranger cooneyes 68 merc box and hood,some supercool fiberglass fenders i scored way back when, 76 f150 disc brake frontend..currently running a 90 5.0HO 4bbl/c4 auto & 3.50 posi...originally a 360/c6 f100 Ranger with dealer added towpack (incl. kelsey hays trailer brake),boxside toolbox,behind the seat stowage & belly tank...only original parts left on 'er are the frame,rear end,rear springs,and rear bumper...
ultraranger
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Re: Disc Brake Swap.. Prop Valve

Post by ultraranger »

quote="mrsnicks"]
michael69 wrote: Look at it this way if it did not make a difference in your braking why go though the trouble to swap to disk :hmm:
Because all the cool kids are doing it? 8)

Patrick[/quote]

...but the nerdy kids go through the trouble to do it right because they actually know what they are doing. :evil:

Well, I don't really consider myself "nerdy" and I'm not the foremost authority on brake systems and I don't know everything there is to know about all Ford brake systems but, by the other side of the token, there is a lot I do know about them and their function.

Most of my front disc brake, or 4-wheel disc brake, conversion experience has mostly dealt with early model Mustangs. I've converted my own Mustangs as well as I have done disc brake conversions (for hire) for a number of other people who have brought me their cars.

The following photos shows some of the disc brake work I have done. This isn't intended as a 'plug' for what I have done/do, especially since very little of what works on an early Mustang will not work on an F100. It is for reference to illustrate and back up that I do have some idea of what I'm talking about when it comes to Ford brake systems.

This blue '65 Mustang belongs to a friend of mine. In 1996, I had removed the front drums and replaced them with Granada front discs. In late 2001/early 2002, I had designed some adapter brackets to adapt Lincoln Mk VII rear discs to Ford 8-inch & 9-inch small bearing rear end housings. My friend agreed to let me use his '65 Mustang as a 'test mule' to see if the adapters I made would work.


Rear drum on the '59 Ford Fairlane small bearing 9-inch rear under the '65 Mustang.

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Process of installing the adapters I had fabricated and the installation of the 11-1/4" ventilated discs.

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In late 2003, I began work on designing some rear disc brake conversion brackets that would adapt '94-2004 SN95 Mustang V6/GT 10.5" solid rear discs & 11.65" ventilated Cobra rear discs to the older Ford 8 & 9-inch small bearing rear end housings. In the fall of 2004, a friend loaned me his '65 fastback, as a test platform, to check these brackets out on.

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Cobra rear 11.65" disc

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6061-T6 billet aluminum adapter bracket I was working on to adapt 13" Cobra front rotors to an early Mustang/Granada disc brake spindle.

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Fitting the Cobra front disc brake components on my '68 Mustang.

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'87-'93 2.3L Fox Mustang brake booster I adapted to fit on the firewall of a '65 Mustang fastback with a '99-2004 SN95 V6 Mustang 4-wheel disc brake master cylinder I installed, as well as the associated fabrication of the brake plumbing.

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2.3L Fox Mustang booster & Lincoln Mk VII 4-wheel disc aluminum master cylinder in a '65 Mustang.

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Checking out a 1995 Ford Explorer 4-wheel disc MC, 2.3L Fox booster in a '65 Mustang.

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Checking out a smaller diameter, but thicker, 5.0L Fox Mustang booster with Explorer MC in a '65 Mustang.

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...decided to install a '96 Ford Windstar 4-wheel disc MC on the 2.3L Fox booster in the '65 Mustang.

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...fabricating up some brake lines...

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...to install a manual-line lock...because this Mustang didn't have any parking brake cables

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Checking out an Explorer MC in my '68 Mustang.

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Checking out a 1996 Mustang GT hydroboost setup in my '68 Mustang.

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Brake system I plumbed up in a 1956 Chevy Bel Air.

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My friend's '65 F100 he brought to me to convert the single pot (suicide) brake MC to a dual reservoir MC, after he installed discs on the front of the truck.

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1967 Mustang that was brought to me by a local guy. Among fixing/replacing a lot of stuff on the Mustang, I changed out the 4-lug drums for 5-lug Granada discs on the front and I swapped out the anemic Ford 7-1/4" rear end for a 5-lug Ford 8-inch drum brake rear from a '69 Mustang.

Before:
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...after MUCH work:
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As I said, I don't know everything there is to know about about Ford brakes, but on the other side of that, I do have a vast amount of knowledge and hands-on experience with them. :wink:
Steve

1969 SWB F100 Ranger. 240-6, C-4, 9" N-case 31-spline Traction-Lok w/3.50 gears.

1968 Mustang. My high school car. Owned since 1982.

2003 Azure Blue Mustang Mach1.
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