Steering, Suspension, & Brakes

I think I'm going to try again before I resort to having a shop do them. Been thinking about how I went about it & believe some simple changes may improve the results...

First, de-burring the inside when the line is cut. I have two tube cutters. One is bigger & has a deburring tool on it but it's too big to do 3/16 brake lines. The other is smaller but doesn't have a deburr tool. So, i used a small screwdriver ground to make an edge. Is there a better way to make a deburring tool? If not, I'll need to get a cutter with one small enough.

Next, I've seen a few web sites that suggest sanding the outside of the tube with emery paper after cutting. Using a tubing cutter, the outer surface of tube doesn't appear to be damaged or marred so I didn't do that... should I?

Next, I read that the outter edge should be champhered 45* about 1/2 the thickness of the tube prior to making the flare. Do those of you who've been successful making brake lines do that? If so, how do you go about it? I used a file & lightly champhered the edge by hand, but am thinking the file is probably too coarse & that may be part of why my flares are leaking.

Last, when using the flare tool, when you tighten down the "cone" to make the inverted portion of the flare, how tight to you go. I went till it seemed snug, but didn't really bear down on it. I'm wondering if I didn't crank it hard enough to get a good flare?

Let me know your thoughts on these things.

I cut it with a tubing cutter.
Bought a $30 flaring kit off Amazon.
No sanding, no filing, I just made sure it was super tight in the holder and cranked down on the flare.
It seemed so easy that the first time I thought I'd done something wrong, but all of them worked just fine.
No leaks, no drama, no nothing.

The secret - I think - is to make sure the tube can't move while you are cranking the cone down. A friend tried with the same kit and had no end of trouble. He wasn't as enthusiastic tightening things though...

did you do single flares or double inverted? With single flares, you just tighten the cone piece down. For double inverted you first tighten down with a disc piece that sort of forms a bubble flare, then you remove the disk & tighten the cone piece.

Actually I've done both - I have two different kits.
Same story both times.

Rob, I did both the inverted and the bubble flares and had no problems. I just made sure the fixture holding the tubing was SECURE and followed the directions. The only bubble flares were at the rear axle where the tee union went to the chassis. The rest were inverted flares. Only caution, there is a special set of tool for flaring stainless tubing. the regular tool will not grip the SS tubing and let it slide down rather than flaring it properly. See you in Townsend!

No other suggestions related to the questions above?

Kelly, I'm sure the tubing isn't moving in the flaring tool. The holes the tube goes through are threaded (look to be threaded, may be concentric circles) & leave light indentations on the tubing -- I can tell the tube isn't moving from that. Has to be something to do with either how I deburred the inside, how I champhered the outside, or maybe how I tightened them down (not enought/too much/regular wrench vs. flare nut wrench)??

I just read a post on this topic on another forum that says you shouldn't use the sections of brake line that come with flares/fittings already on them to hand flare -- says the brake line isn't annealed so doesn't make a good flare... anyone else had that problem? I got all my brake line from the local auto parts store... used one end & cut flared, the other as needed. Used cutoff pieces & flared both ends for shorter pieces.... could that be part of my problem?

Looking to eliminate the problems before I spend a bunch of time & money on this the 2nd time around.

Rob

Quote:

.... could that be part of my problem?

I don't think so Rob - that's how all my brake lines started life and they ended up just fine.
Don't be afraid to put an effort into cranking down the flaring tool or the cone piece during forming.

Thanks Graham (& Kelly - we've traded emails)... I can't tell you how frustrating it is that the flares are leaking. It's not all that expensive, but it took tons of time to bend the lines -- I have them all nice & tight to the body --- really looked good if I do say so myself. Hate having to do it all again. I'm thinking about whether I can plug the back circuit & work on the front 1st to ensure my replacements aren't leaking before I do the whole car over.

The OEM retaining nuts had a long, unthreaded section at the flare end. If you use retaining nuts that are threaded for their whole length they will not go far enough into the fitting to compress the flare. That is, the nuts witll become tight by jamming themselves into the fitting body, and not by compressing the flares. The nuts with the unthreaded ends are not available at any auto parts stores I know of; they are only available through Moss or similar suppliers. Anyway, this fix solved the problems I have had.

Thanks Larry. Surprisingly, I don't have leaks at the bubble flares -- the only bubble flares I have are at the master cylinder. After that it's 100% "normal" 45 degree inverted flares up to the braided stainless hoses at the wheels. Those are 37* AN flares so I have 45* to AN-3 adapters there.

The bubble flares (which I made) are not leaking
The 37* flares are not leaking
Most of the 45* double inverted flares (that I made) are leaking

Rob, Larry may have the solution. I have only re-used the nuts that were on the lines originally. I re-flared the Ford lines on the rear dif. and also the ones from the clutch M/C to the HTOB. I did inverted flares on the fuel lines. I used steel lines and salvaged the lines from a Chev. Trk. in a Yard. A few of the nuts I used (5/16) came from Summitt. The 3/16 all were from the existing brake lines. I have noticed some nuts had all thread and some were domed on the end as Larry stated. Good Luck!

Rob, my experience is to do as you stated, de burr the inner and outer portion of the tube end after cutting. You want a smooth even surface as any projection will get more pressure than the rest and result in a flare that is off center. A drill bit tip would do just fine for the inner debur, just chuck it up in a cordless variable speed drill and give it a quick shot. For 3/16" line around a 3/8" bit would do fine. As for the outside, there's no tool that I can think of made for that, but a quick bit of sanding with some emery cloth should be all that's needed, the ID is most important.
As for tightening, I run the tool down on the final press until it bottoms out and I can't tighten it any more for a standard double flare, after all if the flare is right it's metal against metal at that point and that's what you want. For a bubble flare I use a bit less pressure to retain the shape of the bubble. Hope this helps.

I did everything Bill said, but I added oil to the cone of the flaring tool. It seem to help alot with the finished flare. Also took a small rat tail file to remove the bur on the inside of the tube, that sometimes the drill bit (or small counter sink bit) won't get.

Preparing to install a narrowed S-10 rear end, from D&D Fabrications, in my 78 MGB [www.aluminumv8.com]

Since I have not had much luck flaring brake lines I decided to contact Classic Tube [www.aluminumv8.com]

They came up with a flexible stainless hose for the rear, with a MG (British) fitting on one end and the S-10 t fitting on the other. I thought it was a pretty good way to go, since now all that is left to do is install US standard brake lines (with fittings already installed) to the new S-10 brakes on the rear axle. It cost $39.95 (plus shipping) from Classic Tube. Best news for me is no flaring! (no kidding)





Edited 1 time(s). Last edit at 11/11/2010 08:33PM by jim0899.