Board logo

Brake fittings
Philbo - 7/5/03 at 12:31 PM

Hi all,

Building a 750MC racing "book" Locost. Got a STM pedal box with twin integral cylinders.

When I screw the brass male brake fitment into the female T-piece (to send fluid to left and right fronts from a single cylinder), the brass flange for the fitment goes tight against the female BEFORE the copper pipe inside has "bit" against the receptor inside the female piece.

Have never done this before, but I kind of expected the copper pipe to be squeezed tight between the brass fitments rather than the fitments go tight before that point was reached (the copper pipe is sort of loose inside the fitments).

Obviously I don't want to balls up the braking system! Does this sound correct or have I got the wrong fitments? I reckon I could always shorten the female sleeve somewhat to give the male piece the chance to penetrate further (ooer).

Cheers!

dozracing - 7/5/03 at 01:10 PM

Sounds like you have incompatible fittings. The "bundy" pipe should be flared and the two fittings crush the flared part to form the seal. If your pipe is loose or not properly crushed you will leak fluid.

You may also have fittings that have different threads. The common size is 3/8 unf and M10x1.0. These two threads will start to thread together but after a while will go tight. You must make sure you have the same threads in both fittings and that they are compatible for length/depth etc.

Kind regards,

Darren

Alan B - 7/5/03 at 01:17 PM

It does sound like the nuts (confusingly in this case the male threaded one) are too short...they should have a few threads left after they have bottomed on the the pipe flange.

Do you have the correct pipe end flare?

Excuse the huge picture...(but at least it's a small file)




Usually it will be the single flare into a tee piece.

Also, I hope your pipes aren't copper and are really "Kunifer"...a copper/nickel alloy..


HTH

Alan

eddymcclements - 7/5/03 at 01:21 PM

quote:
Originally posted by Philbo
When I screw the brass male brake fitment into the female T-piece (to send fluid to left and right fronts from a single cylinder), the brass flange for the fitment goes tight against the female BEFORE the copper pipe inside has "bit" against the receptor inside the female piece.


The male brake pipe nuts commonly come in short and long versions. Sounds like you have "short" and need "long".

As dozracing points out, make sure you're using compatible nuts...where did the T-piece come from? In the past I have obtained them from the bulkheads of the following:-
Mini
Metro
Polo
and IIRC the Mini one may have an extra take-off for a pressure-operated brake light switch.

Cheers,

Eddy

Philbo - 7/5/03 at 01:52 PM

Ta muchly, my fears are confirmed. I'm confident I haven't mismatched UNF and metric as the threads go nicely together - you know how it feels "right". Does sound though as if I have a too long female or a too short male.

I've purchased the lines with the male connectors on and flared, but the flare doesn't look like either of your pictures Alan. It looks like the double but without the foldback - as if the end of the pipe had just been widened a tad. As this doesn't match up with either of your diagrams Alan now I'm a tad worried!

As the male fitments are already on the pipes would it be viable for me to shorten the female connectors slightly?

Of course, the Wilwood cylinders have an incompatible thread on them, so I'm going to have to get an adaptor to convert the thread of that to the female T-piece, but c'est la vie.

Thanks for help chaps, much appreciated.