New brake lines 68 GTS

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markfh

markfh

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Ok, I replaced all my brake system from master cylinder to the brake cylinders. All new preformed lines, both proportional valves, the works. In trying to bleed the lines I find that I have leaks. The line to the rear axle leaks at the proportional valve. The line from the proportioning valve across the firewall leaks on both ends, and badly.

I thought I didn't tighten them enough so for those that leaked I eventually tightened them as much as I could and they still leaked.

Any ideas? I'm at whits end on these and about to replace everything again, from someone else this time.
 
You used the stainless lines right? Stainless lines can be hard to seal. Try tightening then loosening...then tightening then loosening the lines a few times. That seems to help them seat. I know Fine Lines recommends using a small amount of pipe sealant on the back side of the flare.
 
Make sure the line is not on an angle to the fitting. Brake lines should not need pipe sealant or pipe dope.
 
Actually no, I didn't use stainless. I went with the original soft steel lines. I've tried the loosen and re-tighten thing several times and it helped but under pressure two of them ooze but one gushes out between the line and fitting. I'm going to get up close and personal and see if the flanges are damaged or not and if necessary re-flare them.

Someone also suggested inverted flare crush washers but nobody at any of the auto stores around here even know what that is or what it's used for.

*** Update *** I found that inverted flare crush washers are actually called copper flare gaskets and seem to be common in brake line installs.

http://www.jefflilly.com/fabrication/fuel-brake-lines/

and found this

[ame="http://www.amazon.com/Flare-Gasket-Copper-16-PK10/dp/B002KLJ1OI"]Amazon.com: Flare Gasket, Copper, 3/16, PK10: Home Improvement[/ame]

Now all I need to do is figure out what size is needed for each of the fittings that I can't get to seal.

Anybody have measurements for the fittings on the front proportional valve for the front to rear axle line and the line that goes from there to the passenger side fitting? Also, if anyone knows what the size might be for the hard line to flex line is. The fitting on my passenger side from hard line to flex line gurgles and gushes under pressure no matter what I do at this time and these gaskets might be the only thing to fix the problem without replacing parts again.
 
Ok, since I know inquiring minds want to know I did get the copper gaskets for my brake line fittings and finally found the time to work on them. Low and behold they worked perfectly. No fuss, no muss. They tightened snug plus a quarter turn with nary a leak.

After using them in the 3 fittings that leaked I bled the lines and waited to see if any of the other fittings would leak. Alas, two other fittings leaked so after the grand kids leave this weekend I'll use them in all the fittings and be done with it.

My recommendation then is if you replace brake lines use the copper gaskets and save yourself some grief.
 
The big thing on new line fittings is to hold the line so that is goes into its matching port straight on when first tightening. Some fittings, like at wheel cylinders have a longer nut that automatically holds the line straght into the matching port. But for connections like at proportioning valves and distribution blocks and hard-to-rubber line connections, the nuts are short and the line can be entiner the joint a bit cocked even with the nut threading right.

At these connections with short nuts, you need to be sure the hold the new line aligned straight in when first tightening so that the flare is centered on the matching port nipple; if you do so, you will not need anything for a good seal. We just replaced all lines on our '62 Dart; I did the backs while holding things straight. My son, with less experience, did the fronts......he did not hold the lines aligned straight when tightening. Guess where the 2 leaks were....?!? They finally sealed with repeated torquing to 'jesus, this is about the break' torque levels.....

WIth new hard lines, take the time to slightly re-bend the line connections so that they naturally lay into their matching port very straight and you will have good results.

Once a port is tightened with misalignment, then it is either re-flare or use something to seal up the distorted flare. I have not had to use any line gaskets, even with a number of car builds/re-builds (but I may need a couple for this car for piece of mind).
 
Good advice Ham all of which I did. I've done plenty of brake lines in my day but inspecting these before putting in the gaskets showed score marks in two of them that weren't going to seal on their own. The worse being the hard line to flex on the right front. I would have re-flared the lines but found the gaskets and decided to work smart not hard.
 
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