The Stovebolt Site Forums The Parking Lot Big Bolts I made a bad mistake

On the 57 GMC 370 LCF. Just rebuilt everything on the brakes. I had a nice tubing bender, so I bought brake lines in the closest lengths possible, already made up. I started buying the steel ones from a local parts store. They were just galvanized looking steel lines. As I progressed on, I needed some more lengths. It was more convienent this time to go to NAPA. The ones they gave me were coated with some kind of paint.
Now I have great brakes but I have leaks at most of the steel color ones. The fitting does not want to spin on the line to tighten up. The whole line wants to turn. The colored lines from NAPA have no leaks at all.
Sure do hate to have to replace all those other lines again. (sigh)

Haven't had that particular problem with new lines. I've used both plain steel lines from advanced auto and painted or coated from NAPA. Leaks I've had a few. I've had old lines twist in two with nut frozen to line.

I haven't had that problem before either, not with new lines.
What does the parts store you got them from say about the problem?

I have not contacted them about the problem, didn't expect much of an answer from them.
I have sprayed the fittings with brake cleaner, and the leak comes from between the nut and the line. Therefore it seems the flare is not seating. I have re-tightened as much as I dare, without cracking the brass fittings.
Do you think maybe screw the line fitting all way off, and put a light coat of grease on the nut where it seats on the flare, and re-tighten?

When I buy lines at O'reillys I have to be REAL CAREFULL not to get METRIC. They look the same and the tags are sometimes missing. Some are color coded and some are not. Just mentioning that in case that is the problem. Like threads on like threads don't leak. Flare is different on Metric.

Maybe thats the problem, I will go back and check with them to make sure. These had green tags on them, but actually I did not read them. The threads seemed to run easy on the old fittings.
Thanks for the tip.

One has to be very careful because just about all European and Asian brake line fittings are metric and since 1980 some domestic use metric and some imperial. There are some metric that are slightly smaller than imperial and screw in too easy. To complicate matters, many parts counter people are no help what soever in this matter. To complicate matters even more NPT threads are the same in the US as well as Europe. A 1/2" pipe thread is the same on both sides of the water.

I seem to remember green is metric.!!! Only buy the tagged/marked lines with proper SAE threads delineated. People bring the unused lines back and they get mixed up. I buy a whole bunch of lengths and take back the ones I don't use.

Thanks for the tips,guys!! I'll be doin' a whole brake up-grade,later this Spring,including ALL the rubber and steel lines. This topic just saved me a BUNCH of TIME AND HEADACHE!! Hope your problem can be remedied,easily,OLD G.M.C. GOLD!! Best of luck!!

Well I did go back and check. He swears these are not metric and nothing on the green tag says anything except 1/4" OD. He said he had been selling this same line for years and no problems.
Mine had a green tag on the line and the nut was steel colored also.
He showed me his metric lines and they did have a GREEN nut, but a purple tag on the line, and did say 10mm.
Soooo back to square one.....Guess if the film of grease don't work, I will replace them all with NAPA.
By the way, I don't even know what brand name his store is. It just goes by: City Auto Parts. He does have access to Cardone brake parts.
Thanks to all.

I did have trouble with the green protective coating. For some reason I sanded on them, "gooed" it up and the nut would not rotate and so on. Took them back for new ones and didn't touch the coating. Worked well. Do you have leaks at where the City Auto Parts line meets Napa line? Could be the Napa coated ones. Anyway, you do have to retighten sometimes to stop leaks. Just don't mess with that coating or it will contaminate the threads and it will "goo" into space between nut and tube. It's not just paint, it's epoxy coating or plastic coating or ?? Take a known SAE male and female thread with you to test each end of each piece you buy.

I'm not pushing any store but the first thing I'd do is visit another store.... any new lines I've seen for a while should say on the tags exactly what they are. Should say if its "standard SAE thread or metric. Shop around before you really screw something up. Brake lines are cheap.

...had a rusted, leaking line on my step son's Dodge pickup. I bought some line and a fitting. Doggone, the new line would work in the union joining them but the original end on the truck would not...CLOSE but no cigars. Turns out the union was the culprit.
...listen to crenwelge, he said a mouth full.

i would look at both type of lines side by side and look at how the flares are flared and are they squared. they should be the same. if they are then maybe its the fitting you are attaching them to ive seen dorked up inverted flare fitting from a not so good tubig job earlier in the trucks life. ive used both type of lines and had no issues yet.

No, I would not say Im having problems where the City Auto meets the NAPA. It's where the lines screw into the original brass fittings. It had a bunch of different types of brass and banjo bolts. I cleaned all the original fittings good and ran a fitting from one of the old brake lines in them to clean the threads.
The NAPA lines do not leak where joining the original brass fittings, but some of the City lines do.
Thanks to all.

I have found easy bend line from napa works quite well it's about twice the price of regular line but is guaranteed not to rust. I comes in 50 foot rolls just bend and flare my own ends with new ends from napa

Can you burnish the fitting in by un tighten and re tighten the fittings 3 times. Sometimes this will help seat the fitting. If that doesn't work you probably have
a seat angle mismatch.