Master cylinder replacement woes

-
Hideogumperjr

Hideogumperjr

Well-Known Member
Joined
Oct 21, 2011
Messages
278
Reaction score
12
Location
Bothell, Wa
I am converting my 63 Dart from single master cylinder to dual. I have the MC mounted fine but have run into problems with the "T".
The rear brake line and the drivers front brake line flared nut have both stripped even using the 3/8" flared wrench. Now I am kinda stuck since the single MC has a broken fitting and I cant swap it back into place.
I am at the point of calling a tow truck from AAA and having the car towed to someone close to do the work MIdas is the closest but I have a bit of fear about their work.
I thought I could get this done pretty easily but the stripped flared fittings have certainly thrown a monkey wrench into the works.
Anyone have a suggestion of my "New Year Madness"?
Thanks in advance.
John
 
I hate to be the bearer of bad news, but if the flare fittings are rounded off, even if you manage to break them loose you'll probably find that the brake line is also fused to the flare nut, ie, the tube will twist as you turn the nut.

Even if they don't, I'm assuming that the reason this bothers you is that you're planning on re-using the old brake lines. Since the flare fittings are already round, you're going to have to replace them anyway, you probably won't be able to get them tight enough again to keep them from leaking. Which means you're already into cutting the lines to replace the flare fittings.

I recently converted a '55 Dodge Coronet over to a dual master cylinder.It ended up being a bigger job than I thought it would be too, I made all new brake lines for it. This wasn't just because of the ancient frozen brake lines though. I'm not sure how your brake block is designed, but since there was only chamber in the master cylinder, I'm guessing there's only 1 input. Which means that the once in the block, the front and rear lines are no longer separate systems. So, you can't "T" the two inputs from the dual master into each other without totally defeating the purpose of having a dual master, one leak would still empty both chambers.

So, I guess what I'm saying is that even if the old brake lines were in good condition, you probably won't be able to use the old lines with a new brake block anyway, and (more than likely) you'll need a new block to make this work properly, one that keeps the front and rear brake lines as separate systems.

I used a brake block off of a '71 Dodge Dart with 4 wheel drums (go figure, I had one). I made up the new lines using the old lines as a pattern, except for the changes needed for the new block (different mounting location). You'll also need to include a brake light pressure switch somewhere in the system, I'm guessing your old single chamber master cylinder had it as an integral part (the '55 did, and they really didn't change them much). So you'll have to plumb that in too.
 
Ditto 72BluNblu on not re-using the Tee (4-port). I went to a dual master on my 65 Dart. I kept the Tee (no stripped nuts here), but removed the rear line and plugged that port (as others have done). No big loss, since what you really need there is a 3-port Tee anyway. Indeed, your existing Tee is funky in that the MC port is a 1/4" inverted flare and would need an adapter to 3/16" tubing anyway (depending on new MC).

For the rear line, you need a 3/16" coupler (2-port) to connect the MC rear port (usually front reservoir) to the rear line. You just need to cut your rear tube a bit further back and add a new brake nut.

You will need a "double flare" tool set ~$30, a tubing cutter (look for mini version at hardware stores) ~$10, and a few brake fittings. Most fittings you can find in the bubble pack racks at Autozone. If not, try Fastenal. Cost will be way under any tow and Midas job and you will keep the tools and knowledge. I used the brake tubing from a newer MC (junkyard). It has braided flex line. Consider installing an adjustable proportioning valve for the rear (~$25 Chinese).

I don't have a warning switch for front/rear imbalance, nor for "low fluid". They weren't a factory design in my 65 Dart or 65 Newport. You can get them in some distribution blocks (say '69 Dart), but most of those have a proportioning valve (fixed setting). You can also get them in high-end after-market adjustable proportioning valves (~$60). I understand the imbalance switch is tricky to set. You must bleed in the fluid to center it. I don't know that they ever worked well in practice. My MC (from ~1996 Breeze) does have a "low fluid" switch, but not sure how it works or how I would wire a dash light. Maybe someday.

Many videos on making brake lines on YouTube. Check out the ones on making a bubble-flare using your double-flare tool. You run into those on many newer cars. There are many types of brake fittings. I think most use 3/16" tubing (even bubble flare lines), though the nuts are various thread sizes to avoid assembly mistakes. The early A's seem unique in that they used a larger 1/4" tube from the MC. Don't connect a 3/16" tube to the 1/4" tube ports, even though you can find a 3/16" nut with the correct thread size.
 
You may be able to find some "off the rack" lines at NAPA or other auto parts stores. They come in various lengths and you can bend them to fit if you're carefull. Otherwise, I think I'd call some of the resto tube places and get a new set that have all the correct bends and wire reinforcement wrap.
 
Thanks yall. Original idea was to use the original T by removing the rear line and connecting a new 3/16 line to the MC with a coupler, which I now have, removing the 1/4 line from the old MC and plugging it, which I did, then connect the other side of the MC to the vacated 3/16 on the T vacated by the rear line.
Didnt go as planned as you can tell!
I am dithering on the idea to just replace the old rear line, its nearly 50 years old but for one it has the wound wire around it, can one safely replace this with a steel line without the wound wire?
Thanks for the quick reply, thought I would have this converted over the weekend, ;-)
Right!
 
Don't know anything about the eBay set up.

But, I can tell you that the wire that's wound around the original lines is more like a spring, once the flare ends are cut off of the old line, it slides right off. It can then be slid right onto your new lines before you flare the ends. That's what I did when I made up the lines for our '55, I just reused the old spiral wound cover.
 
But, I can tell you that the wire that's wound around the original lines is more like a spring, once the flare ends are cut off of the old line, it slides right off. It can then be slid right onto your new lines before you flare the ends. That's what I did when I made up the lines for our '55, I just reused the old spiral wound cover.
Click to expand...


Anyone living in snowbelt is just scratching their heads… Spring just slides off. LOL LOL LOL!!! I wish!
 
I understand, I can see from the two fittings that stripped that the brake line is somewhat fused to the fitting and would most likely twist out with the nut. I also see that the twisted wire is most likely fused to the brake line also, this is up in the Seattle area lots of water and rust not so much salt I dont think but still a problem.
So if I cant get the wire off and I use preformed lines with fittings already installed it becomes a moot point to try and install the twisted wire anyway.
One more fun surprise after another!
But that is part of the "joy" of restoring right? yeah right!
Thanks for the input.
 
I'll probably get beat up for this, but I don't know that you need the wire over-wrap. I don't see it on new cars. Most people assume it was there to help protect the brake lines from abrasion. Sounds reasonable. But then maybe it was there so the guys at the factory could bend the lines around the frame with their bare hands without kinking the tube, kind of like the spring bending tools. Maybe an old factory worker will explain. Anyway, sounds like you want to keep it to look correct.
 
I learned long ago that a slow steady pull with a line wrench will often round off the fitting. More often with elcheapo chinesse tools. I start with a good vise grip plier and a quick hit, snap, break it loose first. Afterwards a common open end wrench will back them out. If the tubing is seized to the fitting, PB blaster sprayeed in a work back and forth will free it most cases.
The simplest and most user friendly tubing bender is a tight wound and tight diameter fit wire coil like a spring. The factory used these in forming the lines. After the line is flared on both ends this type bender cant be removed. So they simply strecthed the coiled wire bender and left it on there. It serves as both a reinforcement to prevent kinks during handling/install and also serves as a heatsink to cool the fliud.
 
You must log in or register to reply here.
-

Back
Top