barbs '69 resto

I'm approaching the third year of a body off restoration on a '69 coupe 350. The body is on and the engine running so far so good until I installed the master cyl. and attempted to bleed brakes. I replaced most of the brake lines with new. A few of the after market lines that were not bent correctly I returned and reused the old ones which were the two lines from the mast. cyl. to the proportioner valve and the very short line from the proportioner valve to the driver front caliper. The main line from front to back leaks at the proportioner valve on the top and the rear crossover line leaks at each brass block. All the original lines have no leaks. I tightened all the fitting that are leaking to the point that they might strip the threads, so tightening is not the solution unfortunately. Does anyone have any tricks of the trade or suggestion to seal the flares against the seats. Buy the way all the blocks and the prop. valve are original and never leaked. I hope someone can help. Thx

...Roger...

I have had good luck using teflon as a thread lube so more pressure is exerted on the flare.

Red 71

Did you take the lines that are leaking off and inspect real carefully to be sure that there are no cracks right at the flare. Also look at the ends to see if it looks like 100% contact on the mating surface. It is possible that when you removed them originally that there was enough binding to cause a crack.

Steve COSD

Are you using flare wrenches. This is the only way to tighten the fittings without destroying them. Get them at sears.

Solid LT1

NO TEFLON! TEFLON BAD! The brake lines use a SAE inverted flare and if your dealing with stainless lines, I find it is helpful to use anti-sieze between the tube and the tubing nut (backside of flare) to allow you to tighten the heck out of the nut without the tube galling. There may be the possibility that the brass blocks are worn out, but not too likely. Hope this helps you out. You also need a set of "flare nut" wrenches to prevent rounding of the nuts when tightening these nuts.

Duke94

For the best seal, use anti-sieze on the tube nut then make sure the tube is STRAIGHT going into the fitting. If you have to, bend the tube as required to get it striaght.

Gary

barbs '69 resto

I removed the rear connector blocks and the prop. valve and it appears that the after market brake line flares are bottoming out on the blocks before the male and female cones have a chance to seal against each other. The prop valve has a gouge in the seat which also impedes the flare to seat fully. I have replaced the proportioner valve with one made by MBM which is identical to the original and am waiting on the blocks and a new crossover line to be delivered in hopes this will fix the problem.
Thx for all the input on the leaking brake fitting problem.

69427

FWIW, I've been fighting an identical issue on my '69 after I had the body off and ran all new lines. It's certainly frustrating.