Proportioning valve leaks

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CheeseRules01!

CheeseRules01!

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Hey guys, I installed an aftermarket adjustable proportioning valve in my Dart, and one of the pipe fittings is leaking. I tightened it as much as possible, still leaks, they are brand new fittings. everything else on it is fine, its just the one pipe fitting. I thought maybe try some Teflon tape, but I feel like brake fluid would just eat through it eventually and leak again. Any suggestions?
 
Repop prop. valves are bad that way. You might have to send it back to the supplier.
 
I'll second the bad flare. Chased that nightmare for 4 weekends. Bad flare on a new line from In line Tube.
 
First you must determine WHAT fittings this device has. Is it US or metric? Pipe thread or other? Brake tubing for older US cars is ALWAYS "inverted flare." That is not just a nickname, it is a specific fitting.

If the valve has pipe thread, you must have inverted flare --to--pipe thread ADAPTERS screwed into the device, and THAT thread MUST have sealer

The inverted flare fittings on the ends of the brake tubing NEVER uses sealer of any sort. They seal directly with the flare seating

Next, did you flare this tube yourself? Did you perhaps use the wrong flare tool? Inverted flare and SAE flare are both 45 degree flare angle. JIC and AN fittings are 37 degree flare, and they are distinctly separate tools.
 
Sometimes repeated loosen and tighten helps flares shape/mate to conform. Works at rear wheel cylinders where its all steel and cast iron. Brass can easier distort and fail before it alters to conform steel.
 
RedFish said:
Sometimes repeated loosen and tighten helps flares shape/mate to conform. Works at rear wheel cylinders where its all steel and cast iron. Brass can easier distort and fail before it alters to conform steel.
Click to expand...

I've found I've had to do that with Stainless lines a few times. Are they Stainless lines?
 
67Dart273 said:
First you must determine WHAT fittings this device has. Is it US or metric? Pipe thread or other? Brake tubing for older US cars is ALWAYS "inverted flare." That is not just a nickname, it is a specific fitting.

If the valve has pipe thread, you must have inverted flare --to--pipe thread ADAPTERS screwed into the device, and THAT thread MUST have sealer

The inverted flare fittings on the ends of the brake tubing NEVER uses sealer of any sort. They seal directly with the flare seating

Next, did you flare this tube yourself? Did you perhaps use the wrong flare tool? Inverted flare and SAE flare are both 45 degree flare angle. JIC and AN fittings are 37 degree flare, and they are distinctly separate tools.
Click to expand...
they are pipe thread adapters for inverted flare lines. I did not flare them myself, they are manufacturer double flares. There is nothing wrong with the flares because nothing is leaking out of the brake line fittings, the adapter fittings with the pipe thread that go into the valve are whats leaking. Now, you mentioned using sealer on them, what kind do you use? Just regular old silicone? I have some Permatex Right Stuff I could put on them, that stuff works pretty well.
 
Loctite 545 for the pipe fittings only, make sure the threads are still good after assembling and disassembling multiple times
 
Just to be sure, there is not a seat in the hole the adapter is going into?

Also both hole and adapter are pipe threads?
 
I returned one for this very reason. When I removed the fitting to look at the threads, there was a very prominent gouge running through the entire threaded portion — no wonder it leaked. The replacement also leaked at first, but I loosened and tightened the fitting and it seems to be OK now. Bad QC from the manufacturer.
 
I tried an after market prop valve for my disc conversion, same issues. Felt like I had to tourque the line too much to slow the leaks. Not good.
Switched to a 74 used prop valve, no leaks. Just had to buff the housing, looks brand new. Better fit overall.
 
I recently had an issue like this with my stainless brake line leaking on my new proportioning valve. Took the entire rear brake line off the car. Turned out the flare got a burr on it somehow and it would just not seal in the new valve. Lightly sanded on it with a file and that solved the issue. It is also not uncommon for flares on OEM lines to develop small cracks. It doesn't cost too much to buy a new line if you need to, but I have also heard that the adjustable proportioning valves can be a problem. I didn't even bother to install the adjustable valve on my car. Just installed the correct proportioning valve.
 
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