Brake line nut running out of thread before line is tight to hose (new hoses)

[Cobra4B]

Had new front hoses made by the group that does the brakes for GM's C6R team (i.e. they know what they're doing). Send the ones off the car for them to copy. They look perfect, but the line nut screws all the way in and runs out of thread before the line is 100% seated in the hose. It looks like it could use one more thread. Went back to the original lines and the nuts threaded in and checked up fine. They have just a tiny amount of one thread showing so it's not like there are 3 or 4 threads of the line nut showing. It appears a line nut with a couple more threads would do the trick and work with both lines. So that brings me to my question....

Do different brands of brake hose ends need their own line nuts? The lines look identical and the area where the line seats looks the same too.

Going to run the original lines for now as they pressure tested fine and cleaned up fine.

I guess over time the double flare at the end of the hard line can get compressed to the point the line nut has to thread in farther and farther? I wonder if a new hard line with a fresh flare would do the trick?

~Brian

[Panoz60]

Originally Posted by Cobra4B

Do different brands of brake hose ends need their own line nuts? The lines look identical and the area where the line seats looks the same too.

Going to run the original lines for now as they pressure tested fine and cleaned up fine.

I guess over time the double flare at the end of the hard line can get compressed to the point the line nut has to thread in farther and farther? I wonder if a new hard line with a fresh flare would do the trick?

~Brian

Brian- my experience- is YES, they are not all created equal. My bet is your new lines (from Pratt/Miller?) are caliper specific. ??? I personally think that any compression of the flare would be so minimal that it would be measured with a micrometer. In other words, not enough to account for an entire thread or more. Just FYI- inverted flares normally only require 10-20 ftlbs to seat/tighten/secure them. My experience is that these are all too often over-tightened.
Is your problem at the hardline/hose juntion, or at the calper? If at the caliper- Stupid question...are you sure that the inside of your threaded hole in the caliper is an inverted flare? I ask; because many calpers have an NPT threaded hole for an NPT/Inverted flare adapter fitting. If at the junction, have you thought of a new adapter? Ie: http://pitstopusa.com/c-134232-fitti...-fittings.html Chepaer than a new line.

FYI- I get my flex lines from Allstar, a big circle track part manufacturer. Cheap, and never a problem.

[Panoz60]

Originally Posted by Cobra4B

but the line nut screws all the way in and runs out of thread before the line is 100% seated in the hose.

I was re-reading this and then my response. I'm confused. Are you saying that your hard line connects directly to your hose without an adapter? If so, I have never seen that. I've always seen an adaptive fitting between the two. Then again, maybe it is and I can ring this up as learning something new.

[Cobra4B]

Its like every other car. The chassis end of the brake hose has a fitting on it that the hard line goes into and gets secured with the line nut. This is all chassis side, not caliper. Her's a shot... this is with the old hose installed w/o issue. You can just barely see a thread on the line nut. With the new hose (same exact looking chassis side fitting) the line nut would run out of threads i.e. it wouldn't screw in anymore and the hard line wasn't tight to the hose fitting. Some aspect of the new hose seems to need an line nut with one more thread.

[Panoz60]

Ok, that certainly explains it. Sorry, I don't have any helpful suggestions. I don't know if you accessed the hyperlink in my previous post/answer, but that's what I have always used (on racecars). The hoses I use have AN Female ends. -3 or-4 depending on the application. I'm not familiar with that set-up in the pic. And FYI, my Panoz goes from hardline- to adapter- to hose.

[DeltaP]

Not sure what size line nut that is but they do make "long nuts" with additional threads. The lines will have to be cut and reflared. HTH

[Cobra4B]

Basically those fittings you linked to are what's on the end of the brake hose. I've never had a car that used one like that though. The fitting that accepts the line nut is always part of the flexible brake hose assembly.

The old hoses are/were fine so I just cleaned them up and re-installed. Will talk to the folks that made the new lines about what's going on and see what they say. It appears the line nuts on the existing panoz hard lines just don't play nice with the chassis-side fittings on the new hoses.

[CMPanoz]

When I had my issue with the brake mounting bracket at Road Atlanta I ran down to summit for some replacement braided stainless steel hoses. We could not find anything to match up. After further investigation, I discovered that someone in the past had used a combination of AN and Flare fittings on the car. They actually had AN to Flare connections. Not sure how these ever held pressure, but they did. Check to make sure your connections are "like" fittings.