new brake lines

[Aaron]

I bleed my new brakes today and now have found several leaks where lines go into either the little 3 way split or into the rubber brake hoses. I spent several hours taking them off and trying to bend them so they go in straighter.

Can these lines be that picky? How the heck do I get these to stop leaking?

Aaron

[Guest Dave Claussen]

First, the obvious question-Did you use flare fittings of the correct angle? There are two different angles (45 and 37 degree) and most(or all) brake line fittings use the 37 degree double flare. If the answer is yes to that question then look closely at the flares themselves and make sure they aren't cracked from the flaring process. Even a small crack can cause a leak. Flaring brake lines takes a little practice to get it right. Quality flaring tools are worth the price you pay for them in lack of frustration alone. Also, the fittings must be tightened but not so tight that it would cause the flares or the fittings to distort or crack. Remember that this is a pressurized system that will show you any places that are not done correctly as soon as you apply pressure to the pedal. If only some of your connections are leaking then you must have done something right along the way. Either that or the ones with the biggest problems showed up first. So the short answer would be, yeah, sometimes they can be that picky. Don't give up the ship yet, you'll eventually get them to seal up. Good luck.

[oldmopar]

If you have tightened the existing line and it still leaks the flare or threads my be damaged and the line should be replaced. I use preformed line from napa basically straight sections that you bend as needed this way they are already flared.

Ed

[Aaron]

I think you are on to something Dave. I have attached a picture that shows the old line and what the flare looks like and the new line I am using and what that flare looks like.

Please tell me what type of flare the old line has on it.

I bought all my new line from NAPA, but doesn't look to be the right stuff.

Look like I may end up tearing off all the new lines I put on! Crap

[Merle Coggins]

Looks like maybe you got lines with a bubble flare instead of the inverted seat type. I think the bubble flare lines are used on some import vehicles.

Merle

[Aaron]

Here is what I have learned so far. Most all standard double flare line you buy now at the local auto parts store is a 45 degree flare. You can also buy the bubble flare which is definitely not what I bought. From the looks of my old line I need the 37 degree flare which according to my local auto parts stores you can't get. They can't even get me a flaring tool that will make a 37 degree flare.

Right now I'm not sure what i'm going to do as most of my connections are leaking with this new line I put on.

Anybody know of a place to buy line with a 37 degree double flare??

Aaron

[Reg Evans]

Aaron,

I have redone brake lines on at least 5 cars with this little set made by NEIKO TOOLS. I can't find anywhere on the tool if it is 45 or 37 degree but I haven't had any leaks. I usually buy the brake line in bulk.

[Don Coatney]

First, the obvious question-Did you use flare fittings of the correct angle? There are two different angles (45 and 37 degree) and most(or all) brake line fittings use the 37 degree double flare.

Follow this link for information on the flare angle definitions and what is used where.

http://www.fordmuscle.com/archives/2004/12/ANfittings/index.php

Most brake lines use the 45 degree double flare.

[grey beard]

Aaron,

I spent many years of my life teaching automotive students how to make double flare unions - AND watching a few of them do it wrong, over and over. Yours pictured are sadly not correct for our trucks. The flare fittings you make must be double flared and of the proper degree, as mentioned above in this thread. This is easy to do once you have had someone show you the correct procedure. How straight the tubing bends are where they enter toe flare nut is hot really imporrtant for a good seal, but a proper flare and correct nut are necessary for a leak-free fitting.

Try to find soeone locally who can show you how to make one double flare. Once you have seen one made, you will have no problem turning them out as needed. Also, if you are contemplating making all new brake lines for your Pilorthouse, an inexpensive tubing bender tool is a good investment, and will make your job look much more professional. JMHO

Good Luck. Tell us how the job turns out.

[Guest Dave Claussen]

Don, I humbly stand corrected. I should have done my homework before leading a fellow truck guy astray. My apologies Aaron!! So I did a Google search and came up with this link that clearly shows the use of a 45 degree flaring tool to make a double flare. Guess I should have done the search first.

http://www.stu-offroad.com/suspension/flaretool/ft-1.htm

Hope this makes up for me being such a goof. DOH!! Dave

[grey beard]

Aaron,

The flare on the right in your photo may be okay - sort of difficult to tell from the pic. To answer your pm question, only double flares may ever be used for automotive brakes. Single flares are just not strong enough for the hydraulic pressure that is generated in these systems.

Especially with our older single reservoir master cylinder systems, all our eggs are figurartively in one basket. This means that if any fitting or component in the entire hydraulic brake circuit were to fail, there would be no brakes left other than the emergency. Therefore I recomnmend sgrongly to you to use only approved double flares on all your brake lines. AND it is never appropriate to use copper or any material other than steel for these lines, for the same reason. JMHO

[Aaron]

I have good news to report. I seemed to have all the leaks fixed, all 6 of them... I put on a couple new lines and re-positioned some of the others. I think my biggest problem was that my lines were not going in straight enough and just that slight off center caused them to leak even though they were tight.

I got everything bled and my brakes work! First time the truck has had brakes in 20+ years...

Thanks for the ideas and advice everyone!

Here are some pictures from my brake project...