waynesi

I recently discovered that split developed in the hard line of the breaking system of my car. It is 96 E320 w/ABS and the affected line was that which runs around the engine compartment to serve the passenger front wheel.
I carefuly cut the line with a tubing cutter in a more-or-less accessable spot, flared the two ends and joined them and returned the new section of line back to the ABS unit. Refilled and thoroughly bled the entire system with DOT 4+ fluid, checked for leaks, and it looks like the job is complete.
I know replacing the entire run is the best bet, but is it unheard of to splice hard brake lines, where access to the replacing the entire line is only possible if the engine compartment is empty??

Please advise.

Wayne SI

PS, I bled the system using the two-person method until clear fluid ran from each bleeder port, and the pedal has never felt more firm. I have test ridden it stopping from incrimentaly higher speeds, and also performed an "emergency stop" ... no problems, no leaks...
Am I worrying about nothing or is this a disaster waiting to happen???

mleskovar

You are worrying about the right thing.....safety. I have never had to repair a brake line but I don't see why it wouldn't work. A good joint should perform just like a solid line.

vettdvr

The flares in a brake system use a double flare. This can be done with a special tool. If you used the single flare as on water systems there is the posibility the flare could split under pressure and have no brakes.

So to answer your question. Yes you can repair the line by splicing with a

But

YOU MUST USE THE DOUBLE FLARE TO PREVENT SPLITTING AND BRAKE FAILURE

If you can't double flare you should replace the line.

Do some research on the double flare and you will see the tools and methods. This web site will show the safe way to double flare for brake systems.

http://www.carcraft.com/howto/50919/index.html

Best of luck. Jim

waynesi

Thanks for the replies, to clarify... Yes, I did use a double flare tool in mending the line, so I am very confident that all should be well... the flares looked beautyful, and the fittings matched up very smoothly. The only thing I didnt do, however, is use a file to pefectly square the ends or use an emory cloth to clean the ends before flaring, as was suggested in the link vettdvr provided.. If you guys think that it is that important, I can always cut and reflare the line, as I did leave a little extra line to play with. (just in case)

Please let me know what you think!


regards,
Wayne

Yacht Master

Wayne the repair is ok to do, but the orginal brake line was defective, so one could conclude that the part that remains could suffer the same failure. You have a tempoary condition now and, it might be in your best interest to replace the remainder of the orginal brake line. my $0.02

waynesi

A valid point, Yacht Master... knowing how easy it is now, I probably will take your advice. One thing I didnt mention on earlier posts, is that it looked like the line had been kinked and straightened out, as when i was looking at the split, there was definately a crease in the line... so, I'm thinking that maybe the technician who was running the lines for the braking system, didnt want to replace the line, or thought it wasnt signifigant enough to warrant rerunning the entire line. The split occured on one of the final bends before being attatched to the ABS unit.

Thanks for the reply.

Wayne

PS. your .02 cents were appreciated!

sosh

Quite frankly, I would just replace the line with the correct one piece tube. This is the primary safety system in the car and any splice even with a double flare is not as leak proof or as strong as a non spliced tube. Yours could have cracked for one of several reasons; defective tubing, vibration, not secured or clamped correctly or perhaps whoever did the bending damaged it. It is quite old but still should not have split. If this occurred on an aircraft a spliced tube would not be allowed and the aircraft would be grounded untill it was corrected properly. Remember also that it must withstand very high pressures.

mleskovar

I'ts at least as leak proof as the standard terminations of the complete brake line. Right? That's like saying you shouldn't patch a tire because it will never be as strong in that one spot. Not looking to argue, I just think he did the repair right and shouldn't worry about it.

lkchris

Suppose this repair is approved for critical aircraft hydraulic systems?

vettdvr

[QUOTE=waynesi;2197011]One thing I didnt mention on earlier posts, is that it looked like the line had been kinked and straightened out, as when i was looking at the split, there was definately a crease in the line... QUOTE]

If there was a crease in the line you had a stress concentration point and this is reason for failure. Given you did double flare and it isn't leaking now and you have it secure where it is secure from vibrations you are probably ok.
If the line had not been creased I would be concerned about the rest of the line but since you had a specific reason for the failure and repaired with the double flare you should be ok. I would not worry about sanding / squaring the double flare. This it to help prevent leaks but if you aren't leaking it should not be an issue.

I know a new line would be better, but if the flare isn't leaking now and there is no abnormal vibration this should be as strong as the line itself. But if it bothers you to drive it you could replace it as others mentioned.

Jim