1970s 70s Brake System Rebuilds

[bcroe]

With all my cars here in the rust belt between
4 and 5 decades old, total rebuild of the brake
systems is a reoccuring thing.  Cylinders and
calipers jam or leak, hoses break or do strange
things, lines turn into rust.  As with all front
to rear plumbing, I replaced the pipes with rust
resistant materials such as SS or copper-nickel. 
other hardware might be replaced too.  Drums and
discs are fine, I have been taking care of them
and minimize use of the brakes.  All this would
extremely expensive to hire done, which is one
reason these cars mostly disappear.  But it costs
little for DIY, parts are not hard to find.  It
is still a pain to deal with all that rust, but
managable with a 2 post lift. 

The lines of a 70s dual circuit brake system are
3/16 or 1/4.  But connected to the proportioning/
distribution block are fittings inlet sizes 1/2
in.-20 and 7/16 in.-24. Outlet sizes to front are
3/8 in.-24 and rear outlet is 9/16 in.-18.  Similar
fittings are on the master cylinder.  It appears
the General used such a variety of fittings so that
it was impossible to connect a line to the wrong
port.  I have taps to clean up threads for these. 

I have been able to find all the needed fittings,
used with a good (read expensive) double flaring
tool.  But there is sometimes a tendency for the
rear wheels lock up before the fronts.  This was
so bad on my 79 Eldo (front and rear discs) that
the car was not safe to drive in wet conditions. 
My initial fix was to install an adjustable
proportioning valve in series with the rear line,
adjusted to about its 9 turn limit.  This cluge
was effective, but continues to be needed even
though all the calipers have now been replaced,
in some cases twice.  Makes me wonder what was
going on from the factory. 

More recently I have seen a 5 port distribution
block with a built in proportioning valve.  That
seemed like a good idea, instead of 2 units.  By
Wilwo..d, complete with switch.  BUT I had issues
with a purchased unit. 

First problem, I did not see instructions on which
port went to which function.  Must be important.

Next the switch turned out to be to drive brake
lights.  I need the switch that detects a failure
level imbalance between the dual circuits. 

Finally all the fittings were of the smallest size. 
I need 2 to be of the largest sizes, to use with
the larger 1/4 in line.  I have not yet found a
way to adapt between 3/16 and 1/4 in lines, no
splice adapters found at my usual sources. 

So it appears, I will continue to use an adjustment
valve separate from the distribution block.  Anybody
see a solution to these problems?  Bruce Roe

[Dave Shepherd]

Bruce, I see there is a union 3/16 to 1/4 inverted flare union, also an adapter into the m/c 1/4 to 3/16. Edelman catalogue has many adapters of varied configurations. I have used a variety of these. Dorman and Inline also make these.

[bcroe]

Bruce, I see there is a union 3/16 to 1/4 inverted flare union, also an adapter into the m/c 1/4 to 3/16. Edelman catalogue has many adapters of varied configurations. I have used a variety of these. Dorman and Inline also make these.

Thanks for the info.  Guess a flare to flare adapter
is going to be the only answer.  I tried looking thru
the Edelman catalogue but did not see that adapter,
do you have the 6 digit part number? 

I am thinking that Wilwo..d may not even maintain
2 different brake circuits, with no failure light
switch, I think I cannot use it.  Bruce Roe

[Dave Shepherd]

Ok, tell me exactly  what you need I have 2 catalogues.

[bcroe]

Ok, tell me exactly
what you need I have 2 catalogues.

3/16 to 1/4 inverted flare union

[TJ Hopland]

Seems like they would make an adapter 'nut' for that or is the problem that the line is 1/4 and the hole is 3/16?

[bcroe]

Seems like they would make an adapter 'nut' for that or is the problem that the line is 1/4 and the hole is 3/16?

There are several dia nuts designed to go over
1/4 in tube to secure the flare.  Same for 3/16
in tube.  But you cannot put a flared 1/4 in tube
into a unit expecting a 3/16 in flare, or the
reverse. 

[Dave Shepherd]

https://www.clipsandfasteners.com/1-Brass-Brake-Line-Union-3-16-x-1-4-Invert-Flare-p/amzbl53020-1.htm

[TJ Hopland]

There are nuts to go one size smaller line in a larger hole.  Just looked at a AGS set I have on hand and I have fittings for both 1/4 and 3/16 lines in a 7/16-24, 1/2-20, 9/16-28.  My 3/16 set is much larger than the 1/4 set so the 3/16 also has metric and bubble options for the 3/16 line. 

https://www.agscompany.com/products/3-16-tube-nut-union-adapter-fitting-assortment-24-8

I'm pretty sure I bought my set from Summit but it doesn't look like they still have it but the company is still around.  Its been a really handy set to have around especially for stuff after the 90's where it seems anything goes including metric and balls.  I want to say when I bought the set it was about $130 which was a lot of money but when I look at how much time I would waste having to go to multiple parts stores when the car was apart and then paying like $10 for the fitting if I could find it or having to come up with a chain of adapters it was well worth it. 

Same with buying a nice tool.  I got a name brand pistol grip hydraulic tool.  Not cheap but sure makes quick and easy work of flares.  Before that I just had a $20 parallel bar setup which served me well but was really only good for 3/16 and a huge pain if you had to do very many or in an awkward spot. 

For anyone curious this is the tool I picked, like everything its gone up a good bit in price in the last couple years.  I went with the pistol grip because it looked like it would fit in tighter spaces than the other style tools both manual and hydraulic.   I'm in the rust belt so I need to do a lot of repairs in awkward places. 
https://www.summitracing.com/parts/urr-pft409     

I don't think I had any special reason to go with AGS other than it seemed like a good assortment at a reasonable price and was in stock where I was shopping for the rest so I had enough to get free shipping. 

I also keep a roll of 3/16" and 1/4" nicop line on hand and yes not cheap but for repairs should last a long time and saves those trips to the store with the car apart.

[bcroe]

https://www.clipsandfasteners.com/1-Brass-Brake-Line-Union-3-16-x-1-4-Invert-Flare-p/amzbl53020-1.htm 

That Clips & Fasteners union does look like the
answer to my adapter question, thanks.  Pretty
expensive, but I guess I should make sure I get
a couple just in case. 

There might be similar outside nuts for either
tubing size.  But you cannot just change the nut
and put a different size tubing into a unit.  I
can imagine an adapter that screws in like a
nut and flare, and takes a different tube on
the other end.  But all those in that kit seem
to be the smaller size. 

I have solved such problems for pipe threads
by drilling and pipe thread tapping a brass
block.  But I cannot tap for an inverted flare. 
Bruce Roe

[Dave Shepherd]

Maybe I misunderstood what the problem is, I have fabricated a lot of custom brake systems in my shop. If you are trying to connect a 3/16 brake line to a 1/4 line that union will work. If you have a m/c or prop valve that needs a reducer adapter 1/4 to 3/16 that is a common fitting

[bcroe]

Maybe I misunderstood what the problem is, I have fabricated a lot of custom brake systems in my shop. If you are trying to connect a 3/16 brake line to a 1/4 line that union will work. If you have a m/c or prop valve that needs a reducer adapter 1/4 to 3/16 that is a common fitting

Yes that union will join them.  I still cannot
use the Wilwo..d combination for the other
stated reasons, so my adjustable proportioning
valve will remain a separate piece. 
thanks, Bruce Roe