My '83 F-150 has a trailer brake control. The hydraulic line to it from the master cylinder was cracked by the PO's mechanic when installing a new carb and manifold. This hydraulic line was 'T'd off the front brake line coming from the master cylinder. I broke the line off getting the fitting out of the 'T'. I tried to re-connect the front brake like to the port where the brass T fitting was, but I couldn't get that fitting started. So, I took the broken off fitting, and the brass "T" to the local O'Reilly's to see if I could get a plug for the brass "T". I got a plug, and had to get a thread adapter to get it to screw into the "T".
The problem is the plug is a loose fit in the adapter. I don't think anti-seize will take up the slack.
Is there a plug available in the thread size of the smaller flared fitting? I am an amature machinist and have a lathe and mill. If necessary, I could make a brass plug. What would you do?

took a picture to clarify...

 

I am guessing the ports in the Tee are for flare fittings like a metal brake line.
The plug you need also needs to be for a flare to fit into the port.
None of the brake lines use NPT as that sounds like what the plug you got that fits loose is and is bottoming out on the flare part of the Tee.
It is the flare that seals not the threads.

They do make flare plugs but might be hard to come by now days.
Also make sure it is for SAE flares and not metric flares as they are different.

So it sounds like you want to plug the open port on the Tee and not use the trailer brake controller?
If so why not get a coupling to replace the Tee and put the 2 metal brake lines together?
If you still want or need to use the controller then you will need to get the brake lines back the way they were or replace the controller with a newer type.

If you do go with a newer type do not get the time delay type. They work based on when the brake lights come on and then ramp up over a set time (you can set this time) till they are on 100%
The other type uses an pendulum and as you brake it swings and sends power to the trailer. The harder you brake the more it swings and more power it sends to the trailer. There is also adjustments for how much power etc. and they work really good.
I got 2 one has been in the truck since new now 21 years. The other is in my 81 F100 that I installed 3 years ago but have not hooked up to my car trailer with yet.

Oh back in the day I have installed and used they type you have and they also work pretty good till the leak at the controller and drop on the floor / rug.
But with today's ABS systems this type will not work and why the above types came out.
Dave ----

 

I don't intend to use the brake controller, and will eventually remove it.
Do you know what size plug I need?
Edit: Dorman lists a 1/4" Flare Nut Plug. I hope that's it!
I need the line plugged to be able to move the truck and keep moisture out of the brake system.

 

Here's the plug you need. I am guessing from the pictures the lines you are working with are 3/16 brake lines. This plug is for 3/16 brake lines that have 3/8-24 threads. If you want to double check this, get a regular fine thread 3/8-24 bolt and see if it threads into where you want the plug. That is the reason why you are having problems with it fitting and sealing, those brake line threads are regular straight machine threads, the seal is the cone in the middle. It doesn't show it in the picture, but this plug should have a concave cone in the middle to seal against the convex cone in your tee fitting.

You said you are a amateur machinist. Are you getting the jist of it? Pipe threads are tapered and seal with the threads and thread tape. Brake line fittings are straight thread and no thread tape is required, they seal with the tapered cone in the middle of the fitting.

 

Was the original factory brake line shortened to make room for the tee fitting? It's much easier to reshape the line if possible, so that's what most installers will do instead of cutting and flaring. Does it look possible to tweak the line and connect directly to the MC and lose the tee?

However you sort it out (Dave is spot on with details of how the different fittings seal up), you'll want to read this before bleeding the brakes:

https://www.ford-trucks.com/forums/1...-bleeding.html

 

I found the original packing the adapter came in. The smaller thread is a 1/4 -24 flared fitting. I found a double flare plug online and ordered a pack of 5.
I might be able to re-form the disconnected front brake line, but I really don't want to risk breaking it.
I do understand the thread specs. I mistakenly relied on the counter dude to give me the right parts.

 

I'm wondering if it's just easier to replace the line from the proportioning valve to the MC with a new, correct line, made of Ni-copper like most of us use to replace the brake lines with. NAPA has a selection in different length's. They are easy to bend by hand and install. The length's come already flared with ends on them. Basically plug and play.

 

99% of the time, a standard brake line nut will not fit the master cylinder. You can get around that by cutting the nut fitting off that comes on the line from the store, slip the old factory nut on the new line, and then re-flare it. That is a another whole can of worms unless you want to learn or already know about double flaring brake lines and have the tool to do it.

P,S, You also maybe able to buy an adapter from the master cylinder size to the standard 3/16 line.

 

I do not have any flare tools or experience making flares. So, it's off to the auto parts store to get an adapter...

 

Is there a reference for our Bullnose trucks that shows what size fitting goes where?

 

Why don't you take a picture of what you have going on. I thought you were going to keep the Tee and get a plug? Someone's suggestion of a coupler would be a possibility? If the line is the same going in the tee and going out, a coupler should work. Then you would not have to mess with the weird fitting going into the master cylinder. They have couplers with the cones made in them on each side of the coupler. Just make sure you get the right thing, as you found out you can't trust the kids at the parts stores.

If the fitting is the same on each side of the tee, then take the tee to the store and buy a coupler the same size. There are many ways to repair this, since you do not have any tools to do it you want the path of least resistance.

 

I did take a picture after the fact and added it to the first post in this thread.
I do have some thread pitch gauges. I'll check the thread sizes.

 

Is the brake line going to the front brakes the same size as the Tee going into the master front port?
If so you already have the Tee out just screw the line into the master.
This way you dont have to deal with the Tee, adapter or plug.

If you really need to move the truck put the Tee back in place and where that broken line went get a short piece of line cut 1 end off and fold the other over 2 or 3 times and compress it as tight as you can to seal it. You should be able to move the truck and have a little pedal.
It will have air in that crimped line making the pedal soft but JUST TO MOVE should be ok.
Dave ----

 

Looks like he has a short piece of flair tube in the picture, so use pliers and crimp the very end, then fill the tube with JB weld and stick in the tee. Let it cure a bit before installing.

 

FWIW, I don't understand why you just can't install the original brake line into the port on the MC. When I replaced my MC a few years back, the old one had some adaptor brass fitting. I just threaded the old original brake line into the new MC. My new brake parts come from my local NAPA.