So I need to replace one of my rear break lines. I noticed that one has some sort of connector on it. about midway from the valve to the rear. I'm wondering if both lines have this or just one. as it would be easier to change then replacing the whole line. also am I right that I'm going to have to remove the aux tank to do this. I have the skid-plate off already as I was looking to see how hard this was going to be.

 

There is only one rear brake line and it is made up in two sections. That connector is called a "union"... it's a inverted female flare (IFF) on both ends.

I don't have an auxiliary tank but I think yes, it will need to be removed to access the plastic clips which secure the brake line to the inner frame rail.

Better to drain the tank and make it as light as possible. It can get quite wobbly with fuel sloshing around. Gasoline weighs about seven pounds per gallon so imagine a light bowling ball wandering around in the tank as it is lowered.

If you are inclined to try your hand at making your own lines, order a 25-foot coil and fittings from Speedway Motors and the tools shown here: https://www.ford-trucks.com/forums/1...l#post13542395

and here: https://www.ford-trucks.com/forums/1...l#post13542586

 

ok so looking at the break lines i'm completely confused because there looks to be two lines going to the rear from the valve.


looking at this photo ( i know its bad but hay its 0330 most people don't crawl under a truck in the middle of the night lol) the upper line on the left hand side is the cut line and it heads to the back of the truck. as seen in the next photo its the bottom line



the line with the union connector is the only line that goes all the way to the back without any issue. so i'm totally confused because again looking at this photo you have the fuel line and then under it the broken break line follows the same path. as the one with the union connector.

 

Your truck has brakes.

 

From your brake proportioning valve at the front of the line, you should have two coming in from the master cylinder and three lines going out - one to each front brake and the other to the rear brake line mounted left-front above the rear end. From there a rubber line with a "Y" connector come down to your rear end and from there you will have one brake line going to each rear wheel.
Does that match up with what you have.
I think the other line you are seeing is the fuel line.
Brake lines are 3/16th, small. The larger looks like a fuel line.

 

Food for thought, if you are having to replace that brake line due to rust, you might want to consider replacing them all.

 

The line I need to replace has been cut. It's to perfect to not have been cut with a cutter

 

Well, either somebody doesn't like you or you been to the wrong repair shop.

 

The line was cut by I'm thinking the po.

 

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Lets have a picture of your cut line. Steel or rubber flex line??
orich

 

The brake valve you have is a pressure differential valve for all-wheel drum brakes. There isn't a proportioning or metering valve inside that assembly. --Those two items would be in a valve assembly for a truck with discs front/drums rear.

The (3) lines on the upper half of the pressure differential valve are for the primary side (front) brakes. One line, from the primary port of the MC (the port on MC closest to the firewall), will come into one of the (3) ports at the upper half of the valve. The other two lines, on the top half of the valve, will branch out (one each) to the front wheels.

The two lines on the bottom half of the PDV will be for the secondary (rear) brake circuit. The line located on the lower right of the valve will be coming from the MCs secondary port (the MC port that's closest to the radiator). The line on the lower left of the valve is the line leading to the rear brakes.

The tubing diameter of the hard lines is 3/16" (same diameter as metric 4.75mm tubing). 3/8"-24 is the standard inverted flare nut fitting size for 3/16" brake tubing. However, the flare nut, on the tubing at the valve going to the rear brakes, is a 7/16"-24 inverted flare fitting and will require a 7/16" flare nut line wrench to break the fitting loose --if you have to unscrew it from the PDV.

 

after dropping the aux tank I found that the second line that was confusing me is a line that replaced the old cut line. So it looks like I just need to set the warning light and re-bleed the breaks.

 

It's B-R-A-K-E-S.

... or are ya just tormenting us?

 

nope its true what the po did was cut the old line and instead of removing the old line the left it and ziptied the new line to the tank strap. i'll order that bleeder thing and bleed them properly