Re: [alfa] Re: alfa] hard brake lines

[Richard Welty <rwelty@xxxxxxxxxxxxxxx>]

On Tue, 16 Dec 2003 10:42:40 -0500 Andy Kress <aokress@domain.elided> wrote:

> Richard's advice is generally right on.  however, i believe the spider 
> fittings are actually 3/8-24 thread.  i too thought they were 10mm, but 
> after careful review on the playing field, turns out they are english?
> perhaps left over from the Girling/Lucas days.  it is amazing that it will 
> fit a 10mm thread though.

hmmm.

i'd verify the thread before buying anything, then. my alfetta definitely
had M10 brake fittings with ISO bubble flares throughout.

3/8-24 is the same thread used by 3AN [1], but in general, automotive flares
are 45 degrees and aircraft (AN) flares are 37 degrees. do _not_ mix
without adapters. because the threads are the same, a lot of folks
assume that they fit and get into trouble. a friend of mine who used to run
an RX-7 at track events converted to AN type flexible brake lines without
understanding this, and was amazed when i explained it to him. it
provided a complete explanation of why he was getting about a 60%
success rate of keeping his fancy brake lines from leaking.

> I;d say reuse the old ones if they are OK.  3/16 (4mm) is what is on the 
> car.  double flare for brake lines (single for AN - 3AN is the right size).

there are two types of double flare. the metric stuff uses what is called
a bubble flare, where from the side it has a "diamond" shape. the SAE
flares (english thread) use a double flare, but the second part of the flare
is folded back in, so it looks like a single flare but with reinforcement.

using single flares with SAE fittings is asking for trouble, but it's correct
practice with AN fittings.

richard
[1] AN stands for "Army-Navy". the system was introduced going into
WWII as before that there was nothing standard about aircraft plumbing,
just as there was nothing standard about electronic diagrams at the
time. the AN system is very easy to work with and very reliable; it was
designed so that your basic high school dropout aircraft mechanic could
correctly assemble it on remote pacific islands with simple hand tools.
-- 
Richard Welty                                         rwelty@domain.elided
Averill Park Networking                                         518-573-7592
    Java, PHP, PostgreSQL, Unix, Linux, IP Network Engineering, Security
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