The Stovebolt Site Forums The Shop Area Driveline Brake line flare problems

Trying to install new brake lines and keep getting small creases In the flare. I’m not using one of the expensive flaring tools but it’s a single size tool for 3/16” lines (see pictures). I have been practicing and making sure to deburr inner and outer of line but still occasionally get the crease that on 1/4 to 1/3 of the tube circumference. I’m interested if anyone has tips on how to improve my method and whether or not these creases are even an issue? See pictures.

Thanks

You would have trouble with that flare trying to get it leak free. I use an older style flare block, a simple one that is also used for single flares. You might have the raw end a little too proud on the first bubble step and the tubing not being supported enough. Try a very small decrease in depth.

The seal is done on the very end of the flare, so I think you're probably OK. As you tighten the nut, that crease will be flattened a bit, and as long as the forward end of the tube is straight in the fitting, it should seal OK.

"It should seal OK" ?
I hope it sort of stops after it fails.

Carl, It should be tested for sealing before committing to the road.

But redoing it would of course be safest.

For years I've said the easiest, fastest, most economical and possibly the safest way is to: 1. measure the length and diameter of all the pieces of line you need. 2. go to O'Reilly's and purchase these (pre-cut with fittings attached). 3. purchase any splitters, connectors, etc plus all flexible lines and 4. install them neatly and without any fuss. Some may be 5 or 6 inches longer than you need? No problem. The stuff bends easily, so just put a couple of small U or W shapes to take up the slack or wrap around into a small loop that will be hidden on the inside of the frame rail. The last time I did this, I believe I spent between $50 and $60 for the hard lines, splitters, connectors...for the entire truck and $30 for all 3 flex lines. Just looking on the O'Reilly's website, here are a couple of examples: 30" copper/nickel line with fittings $10.29, 40" $14.99 60" $17.99 Or you can now buy direct from AGS (American Grease Stick Co): https://agscompany.com/
Good luck.

Summit has the same lines as Orielly’s for about half the price, but you have to pay shipping. Copper nickel is the way to go and pre made lengths are also the way to go. Don’t try to bend stainless it is way to hard, but does look great!

Double flaring, particularly on a steel line, is a skill that has a LONG learning curve. It's doable, but using a fancy (translation: EXPENSIVE) flaring tool makes the job a lot simpler! Don't forget to put the nut onto the line BEFORE you make that perfect flare!
Jerry

I would suggest oiling any moving surface while making your flares. I found that, even with the expensive tool, a little lubrication would prevent the stainless from splitting, which would happen about half the time. Being generous with lube doesn't hurt.

Hence the die lubricant shown in Dongray's picture of his flaring tool.

Thanks Buckshot, I tried it and it did seem to make a difference. I still seems to happen occasionally but it better. Figure I will practice some more before giving it a try on the actual line.

Jon G, I really considered this but wanted to give it a try. I have a coil of line to work with and if I don't get it figured out after the coil is gone that is what I will do.
Thank you, Eric

So glad I ran across this discussion. I was considering ordering all brake lines and fittings pre-made from one of the specialty stores. I can get what I need from O'Reilly's!

Those "pre-made" lines generally need a lot of tweaking, and some just don't fit at all. Using straight lines with flare nuts on both ends, a tube bender, and coupling nuts won't win any concours car shows, but they're probably the simplest, least expensive way to go.
Jerry

Sorry to hear those didn't work for you, Jerry. Were they AGS brand? I can't promise it today, but the last ones I bought were made in the USA and they went on just like magic. There was only one line which was a bit too long and I added a little more arch to the point where it wrapped over to the junction for the front left flex line. The long line (from the passenger side connector piece...by the battery) was originally a split line and it was simple to move the connector to where 2 pieces fit just at the right length. When I looked at their website the other day it looked like they had a nice range of lengths (4", 6", 8" all the way up to several feet in 2 inch increments) made in either flare, bubble end or inverted in either SAE or Metric that you could order directly from them. I tell you in my opinion it was one heck of a lot better than trying to use a cheap double flare tool (which we know isn't worth a spoon of beans) or buying a good one ($$$).

Jon, you misunderstand. I use universal lines and splice nuts all the time. I was referring to the ones that are supposedly bent to fit a specific truck frame. Quite often, I've seen those custom line kits that only vaguely resemble what was there originally, and they needed
a lot of manipulating to make them work. It's been quite a while since I've done a complete re-plumb job, so the quality has probably improved.
Jerry

I didn't even consider ordering custom preformed lines due to my truck being just a little out of the ordinary. It's all 1/4" from the master to the hydrovac and from there to the wheels. At 160" wheelbase the pickup truck lines won't cut it so a 25 ft. roll of cupro-nickel and new rubber lines and I had it made. I flared and bent them to match the old ones as much as possible. I was able to use the original tee's and banjo fittings since they are all brass and clean up real easy. So far so good - no leaks and real good pedal after three years.

Dongray, with the slight crease on the underside of the flare it will put uneven pressure on the actual sealing surface of the flare. The better the flare the easier it will be to tighten it and achieve a leak free joint. If you were working with copper it would form quite easily, the steel or copper-nickel is harder metal and will take a lot more pressure to make the nut squish the sealing face. The flare nut has a matching angle inside of the nut to correspond with underside of the flare and that needs to have a pretty good surface to apply even pressure around the circumference of the flare. Don't get frustrated, keep practicing and you'll get a good feel for it. It's much easier at the work bench to make it right instead of under the truck with brake fluid dripping down your arms.

I understand now, Jerry. You're not the first person who has warned me away from pre-cut/pre-shaped kits.

The best flare tool I’ve actually used is the Eastwood flare tool in this video.



Perfect flares EVERY TIME unless I am careless (in too much of a hurry). I bought a new flare tool that is more portable and have not used it yet. I made a few test flares on some steel line and it seems to be fine. The advantage of the new MASTERCOOL hydraulic tool is that flares can be made “on the vehicle” rather than needing to take the tubing to the workbench. Plus it has more dies to make all sorts of flares that the Eastwood tool doesn’t have in the kit.

I purchased the MASTERCOOL hydraulic tool a while back to make double flare gas lines for a tri-carb set up. I can say, while expensive, it was worth the money. I was disappointed when I was done, I wanted to do more, it was so much fun! Perfect flares every time. For my brake lines (dual master cylinder - disc conversion) I used a combination of store bought lines and some customization using the tool. The Eastwood version looks to be very handy and of quality, I don't think it was available when I was looking for a tool.
don