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A picture is worth 1000 words.
Quote:
Originally Posted by
Jeff W
Did you get different T fittings than the guys you described? I'm still not clear on the adapter to T connections. Although if may feel like NPT and straight threads screw together... it is not correct.
Wikipedia says: "National Pipe Thread Taper (NPT) is a U.S. standard for tapered threads used on threaded pipes and fittings. In contrast to straight threads that are found on a bolt, a taper thread will pull tight and therefore make a fluid-tight seal."
Hello, Jeff.
Due to parts availability, I used two different-sized adapters for the master cylinder outlets with male NPT threads and flaired female threads. The fitting on the left goes from a 1/2" hole to a 1/4" brake line. The one on the right goes from a 7/16" hole to a 3/16" brake line.
Attachment 3449
Tee #1 was complicated because it joins two different sized brake lines and the brake-light switch. Tee #1 seems to have three female NPT inlets. The brake-light switch and the two flaired adapters feel like they are screwing in correctly.
Attachment 3448
Here is a side view of the complicated Tee #1. You can see the flaired fitting on the inside of Tee #2 in the background.
Attachment 3450
Pipe dopes - no pun intended
Noticed the earlier image showing the nut hard-up against the M/C and was going to (prematurely) comment, but decided to read through all the rest. You seem to have it all figured out using the correct adapter fittings.
Having now done about a dozen of these conversions it's so much easier to do than it is to explain. I/we should really do a full-fledged PDF of this step-by-step with detailed pics. The original PDF posted is good, but leaves out a couple important details, like these fittings for one - or the use of 3/16 brake like (which normally comes with the 3/8-24 threads), but adapting them to the two larger nuts. Or options to negate the pressure switch. Real soon now.
And, now, just to clarify fittings and their use... pipe threads are tapered. The teflon or "sealant" are not supposed to act as the seal. The taper provides this. The issue is keeping friction low so you can force the two threads together until they self-seal before they gall (the melting, of sorts, of similar materials by heat or friction). On some materials, like stainless, these similar materials will gall very quickly without a sealant with Teflon, and in some cases still will to some degree. So the use of a Loctite-based Teflon sealer will cure and harden in the absence of air and minimize leaks. Usually the use of sealant, as a sealant, is deemed necessary when the male and female parts have worn or expanded beyond their wear limit - with mixed results.
Teflon tape, if used, needs to begin up about one thread from the end of the male threaded end to keep it out of the system. But great care needs to be given if Teflon tape has been used before. Every strand of it needs to be removed, since even though it is used correctly the first time, the second use of the threaded parts will work these strands forward and inward - towards the flow of fluid - and into the working bits.
Inverted flares need no sealant, as Kenny indicated. The flare (male against female) cause the seal. One issue I have seen when using these large nuts but with 3/16" line size is that the male part (like that inside the M/C) is assuming the larger tubing flare, not the 3/16" size flare. I had one install where I could not get a good seal. So - just putting this out there that it "may be" better to use the adapter fittings as opposed to the large nuts with 3/16" holes. Depends on the machining of the flare inside the M/C.
Since flare fittings don't expand with use, like pipe-thread fittings do, they are a positive seal every time you loosen and tighten them.
So that's all I got to say about that. Happy braking!
;)
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Fred Flintstone just used his feet.
Hello, Roger.
You talked about lubricating pipe threads. Would dipping the brake switch threads in brake fluid work?
I made another revision yesterday. I went to NAPA and bought two "Brake Fit Tube Nuts" (#641-3296 and #641-3322) for 69 cents each and then went to "Just Brakes" and had them attached.
Attachment 3461
The mechanic used a tube cutter to cut the ends off the brake lines. He re-flared the lines with a "bubble flare" and said that this was the flare that my 8-inch brake lines had come with. I made a brief look at the internet about the subject and saw the comment: "Automotive brake lines are always a 45 degree double flare or a DIN (bubble) flare." Here are my bubble flares:
Attachment 3462
Here is an internet photo comparing the bubble and double flares. I need to read more about the difference between the two:
Attachment 3464
Here are what they look like attached. This eliminated two adapters. If the custom flare fittings leak, I can always get a couple of new brake lines and try the adapters.
Attachment 3463
Dual Master Cylinder Conversion
If you decide to buy a double flaring set, I would advise you spend a few extra bucks and buy a good quality brand. Search the internet on what is the best for the buck. I bought a cheaper version and the flares were bad and leaked. Bought a better set and they work great. I agree with Kenny that it is a good purchase and the tubing cutter along with a decent tubing bender will get used again and again. Larry