I've been running the brakelines in my project last couple of days, and two questions came up. Neither really make any difference - I'm just curious if anyone knows. Nothing more than trivia. 1. Std lengths seem to be 8", 20", 30", 40", and 51". Why the 8 and the 51? Why wouldn't they just be in increments of 10? That 51 is really strange. 2. I've always noticed that on any length, the fittings on each end are always different - one is always a few threads longer than the other. I've plumbed the brakes on several cars, and not once has there been a time where the longer fitting was useful, ie shorts on both ends would have been fine. It costs the mfr to have two separate fitting part #s, so there has to be a reason. What is it? I shud be out in the garage instead of asking stupid questions.
In a some of cases you need a longer fitting for the deep hole in the wheel cylinder, and a lot of older vehicles have a short line from the master thru the frame to a block, this very well be hold over styles from years ago and it hasn't been changed out.
I'd have to say it is a built in option to be able to use the short or long in a certain position. Chances are it will fit one way or another in an area depending on clearance required, bore depth on a fitting/cylinder, or reach. If they were both the same length it might not fit the app on both ends should one not be compatible. Did that make any sense? More flexibility.
In situations where one end of the line will be subject to more vibration that the other, you are supposed to use the long fitting on the heavier-vibration end. Idk about the odd sizing...
I believe Dodge started using the short & longer fittings. The lengths, who cares if doing a nice tight brake line job you will end up cutting and re flaring anyway .........................
On the length,i bet if they cut a roll into such &such long they get a certain amount of lines,without much waste.
cleaner to buy a coil of 25' and roll your own, no need for the odd size lengths. I love when I see a brake line bent into an "S" shape to make it shorter!
56P, that makes sense on the tubing lengths. I've been in the manufacturing field, and you're right, they'll do anything they can to maximize use of raw material. That 51" still seems mighty strange, and hard to believe that all the rolls of tube before they make the pieces would be the same length. Maybe that's how it started long ago and it ended up being an SAE standard. RE some of the replies on the fittings, OK, I'll buy that. Tho I've never seen a hole deep enough for the long fitting, that doesn't mean there couldn't be some applications like that. I sure haven't worked on everything. And 4 Woody, whether or not you're supposed to use the longer one for more vibration support, that sure seems like good common sense practice. Thanks HAMBers. Anybody else have ideas here?
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