Brake system- modified 4 wheel disc, Q's and C's

[cpdenton]

From what I understand, the period correct f-super duty trucks didn't have the RABS controller. There was just a double flare fitting coupler there to take its place.

I don't personally own one, but I remember looking for one to delete the RABS valve.

 

[franklin2]

i think your RABS is actually a proportioning valve/sensor.
sorry no time to read, ill do it later.
the adjustable one is on hotrods and race cars,
it does the same but you can control it.
i dont want an adjustable one on mine, i want the correct non ABS disc/disc valve.

As you are finding out, there is no "correct" proportioning valve for your truck, since that configuration never existed on that exact truck. Proportioning valves are designed for the specific vehicle they are designed for since they all have different weights front to rear, different styles of brakes and different system design. Since most of the disc-disc trucks are later model with abs systems incorporated in the design, I am thinking you are not going to find what you need, and are going to have to go to the adjustable route again.

OEM's always had problems with the brake systems on pickups anyway. A loaded pickup acts different and needs different proportioning than a unloaded pickup. That's what all the little gizmos with levers hooked to the rearend were for, and also the rabs system. They all tried to compensate the rear brakes for loaded and unloaded conditions.

I would check on speedway motors site and see what they have that might work. Lots of hotrod stuff there to build your own stuff.

What are you going to do about a parking brake?

 

[IDIoit]

parking brake is mechanical like it should be.
the rear calipers have the e-brake compress.
and leave it in gear, then chalk block it, then yellow ribbons that say "remove before flight"

 

[franklin2]

parking brake is mechanical like it should be.
the rear calipers have the e-brake compress.
and leave it in gear, then chalk block it, then yellow ribbons that say "remove before flight"

I am interested in what caliper you are going to use and what bracket. A lot of people do not like the cadillac caliper, and they are getting more expensive and harder to find also. I had a idea of use a separate mechanical caliper on it's own bracket made by wilwood, but I am not sure if it would work out.

For guys like me who have to get their vehicles inspected, not having a working parking brake is a show stopper.

 

[FORDF250HDXLT]

he's putting car calipers on his truck. calipers from an f-super duty are what ya want.Hooyah!

 

[laserjock]

He bought a kit but I don't think they were caddy calipers.

 

[IDIoit]

they are a smaller metric caliper.
could very well be caddi calipers.
its for the rear, so im not worried about it.

the real test is when i tow a car.

 

[junk]

There is a little propotioning block that screws into the rear brakeline on the master cylinder. They say to use the same one for the rear brakes you have. So use an F-suberduty one for rear disk and F250/350 for rear drums brakes.

Well when I looked at the F-suberduty and F250/350 ones I had they were exactlly the same. Both were just a fluid flow through. VS some I saw online had a valve looking mechanism in them.

So long story longer. I'm not sure it really matters. On Hotrods I put in the manual proportioning valves and call it good.

Jeremy

 

[79jasper]

On the master, isn't it the residual valve?
We've had some pretty in depth discussions on it in the past, but I don't remember the info.

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[IDIoit]

ALL vehicles need the front to back bias.
as we use our front calipers to do most of the stopping.
the rear brakes are just to even it out.
think i will buy an adjustable valve when i do my lines.

and like any vehicle, do some hard brake testing and adjust until i get 4 wheel lock up even.

 

[IDIoit]

this is the proportioning valve im going to be using.
has everything i want.
including getting rid of the brake switch on the pedal!

http://www.ebay.com/itm/Wilwood-Adj...ash=item4d4123c947:g:cxMAAOSwv9hW6rTi&vxp=mtr

 

[theSHERPA]

Tagged for my rear disc kit sitting in a box.


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[IDIoit]

as im getting closer to building my brake system,
i installed the master the other day and cant help but to notice a few things.
the FSD master is a dual port master cylinder, right?
well i have 3 ports.....
and one one of them there appears to be a restriction valve.
could this be to eliminate the use for a proportioning valve?

1 port for front brakes.
1 port for rear brakes.
whats the 3rd one for?

brake switch?

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[79jasper]

I was thinking the cruise control cutout switch also.
But does it have the sensor in the reservoir?

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[IDIoit]

yes, but i havnt decided if im going to use it or not,.
should only be for low brake fluid level, no?