Brake Line Failure

Thought I would post this if it might help avoid an accident.

Was approaching a stop sign with my 1963 CJ5 a few days ago and the brake pedal went to the floor. Found the problem to be that one of the rear lines had broken at the flare. The lines were in like-new condition as far as rust is concerned. The brown shown in the picture is paint.
The PO had put all new brakes on it including hoses and the steel lines. The lines from the tee at the rear differential to the wheel cylinders were a little longer than necessary, so he looped the excess upward. The line was not attached or supported anywhere between the ends. I think that vibration of the unsupported tubing caused a fatigue failure at the flared end.
I replaced the lines and cut them to proper length (I have a double flaring tool), and will now clamp them to the axle with hose clamps and to the differential cover bolts.

 

The original lines are clamped to the housing, and they do not wave in the breeze like this line did. Likely the PO took a standard length line from the parts store and ran the extra above the housing. These lines are also supposed to be covered with spiral stone guard, which I expect helps them to flop around less. You can get the stone guard from Summit and likely other places - https://www.summitracing.com/search/product-line/summit-racing-armor-line-guards

I'm sure the OP's flares are fine, but there is a spec for the flares that requires a radius at the transition between the flare and the tubing. Fedhill has a helpful PDF that shows what your double flares should be - http://www.fedhillusa.com/webnuts/common flares6.pdf

Glad the OP is ok - don't cut corners on brakes!

 

Pretty sure the long side has one clamp.

Kinda think this would not be a problem except for the springy nature of the tubing extending up like that. The stone guard dampens any springy resonance too.

 

That broken line looks like a classic fatigue fracture, likely from being unsupported. As Tim mentioned, there is supposed to be a clamp holding the brake line to the axle tube, I think part number 929-491. The quantity is listed "as requried".
-Donny

 

I thought there was one at the upper right of the diff cover as well.