Doug sez-
> I've installed a new brake mc in a 64TR4 and when I try to screw in the
> fitting for the brake line into the mc, it will not thread, and I cannot
> get it to no matter what angle, position I put it in.
>
> I'm not totally clumsy, so I got the one I had just removed and tried to
> screw the fitting into it, and it goes in with no problem. I went to the
> parts store and got a bolt and nut with the correct threads and tried to
> screw the bolt into the hole in the new mc, and it went in with really no
> problem. I tried the screw into the old mc and it went in with no
problem.
> I then tried the nut on the bolt and it threaded ok, then tried the bolt
on
> the male fitting on the brake line and it had no problem.
>
> If the old fitting goes into the old mc, and the bolt goes into both mc's
> with no problem, and the nut goes on the bolt and the old fitting with no
> problem, then why does the old fitting not thread up with the new mc?
>
> Any ideas would be appreciated. I have a blister on my thumb from all my
> attempts!
Doug-
What we have here is a case of overtightening...
When Magilla Gorilla tightens the nut (really doesn't take much force to go
Too Far here), the bubble flair on the end of the steel line has nowhere to
go, and ends up expanding the lower edge of the nut itself. On a new nut,
the lower edges will be approx parallel, look at yours and you should see
that they are slightly "bowed out" at the lower edge. If you actually
measure the edges, you will find that they are probably a few thou larger
than the threaded hole in the new cylinder. That's why you can't get the
nut
started down into the threads on the new cylinder (with its nice new sharp
crisp full height
threads, unlike the old cylinder that has just had the edges of the nut
remove the tops of the threads). The correct fix for this is to replace the
nut with a new one.
HOWEVER...
In an emergency situation in the field, far from the Mother Country, I have
seen "people" take a fine file and remove the part of the expanded edges on
the nut. "They" did not make the nut shorter, "They" didn't file in that
direction, but merely went around the lower edges of the nut so that they
again approach being parallel. At least that's how "They" said to do it...
You Didn't hear it here...
Magilla in Nor Cal
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