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Unsure about brake flares


turboeric

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I'm building a Westfield Miata. The Westfield kit has all SAE brake fittings throughout, and converts to metric only at the end of the flex line to the caliper. I'm trying to incorporate the Miata ABS into the system, and of course all the fittings on the ABS actuator are ISO/JIC. So, I'm going to have to make up lines with SAE fittings/flares on one end and ISO/JIC on the other.

 

I'm aware of the differences between the threaded bits, and the single/double/bubble distinctions on the flares. I've made Girling flared brake lines on an old Triumph project, so I know the general procedure. What I can't find an answer for is are the ISO/JIC bubbles and single flares different than the SAE? i.e. can I use my old K-D tools flaring tool, or is there a metric specific flaring tool that I need?

 

Thanks guys.

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The Japanese cars typically use either the british thread or JIS which is Japanese Industrial Swivel. JIC (Joint Industry Conference) threads demand a 37 degree flare. SAE (Society of Automotive Engineers) dictate their flare be a 45 degree flare. I that isn't confusing enough, throw the french into the fray and lets not forget the germans. The french developed their own system that doesn't conform to much of anything (any surprise). The german system using a DIN thread pattern which is a metric pattern.

 

I have a hydraulic parts and service business so we run into all of this and a lot more. Did I mention O-ring boss, american pipe, british paralell pipe, british tapered pipe, Kobelco and Komatsu thread patterns ?

 

The good news is that many shops throughout the country can make a brake line using a inch system tubing system and be able to apply a metric end on one end and an american SAE or JIC end on the other.

 

Another way of doing it like the old blacksmith days is to take one type of line and run into a coupling block which you drill out for the size of the tube you have. On the other side you drill out for the size of the other line (metric vs inch), then braze the tubes into the coupling block. For ABS, which typically uses at lead 4 lines in and 2 or more out, having one rectangular block cross drilled can make the job look neat and professional.

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I highly recommend an Aeroquip (Eaton) Port Idenification Kit. The kit contains a booklet, a special pair of calipers, and a series of thread gauges. It's available for around $60 and helped me to figure out the fitting for my brake system. I hope this helps.

Dave

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Thanks guys. Actually, I got a response from Keith at Flyin' Miata on this. It is a standard metric nut on a 45 degree SAE double flare. Odd, but it seems to be correct. At least Bundy tubing is pretty forgiving - I've never had a problem with getting a seal on any flare I've made.

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