Internal flexible brake line failure: it finally happened to me.

[Frank Lee]

Yeah, it is odd, especially with how much old obsolete junk I have/deal with/fix, and how long I've been at it. I've had many a caliper piston or wheel cylinder seize up, and hard brake lines rust through.

[shovel]

First I've heard of this... is it a regional (weather) thing? I've lived mostly in CA and AZ..

I did have those symptoms once, when a front tire on my medium duty tractor threw its tread inboard, that bent the hardline coming out of the frame and slightly kinked it. I never noticed, and the shop never noticed, we tried to diagnose the "funny" (scary!) brakes for over four months before noticing the kink..

[Frank Lee]

OH For Pete's Sake!

I did a post-mortem autopsy on that brake line and found out that the culprit was that stamped bracket that secures the line to the strut! (see pic at beginning of thread)

The corrosion on that bracket grew to such a thickness as to increasingly clamp down on that section of hose, finally virtually pinching it off altogether.

I figured since the hose was "shot" I'd do a destructive autopsy... tried to run a wire through it but couldn't; cut off hose where wire stopped going in and from either end it stopped right at the bracket. Pried the bracket open (AFTER both ends had been cut off) and Voila!- hose opened right up.

Would I have had that knowledge before I could have pried the bracket open without even removing it from the car. I wouldn't have cut up a perfectly good hose and I wouldn't have bought a replacement and did all that work to install it either. So when the passenger side starts doing it I'll know what to do. Actually, I'll be proactive and go pry it open a little bit right now.

In all the ridiculously excessive online research I did for flex hose failures I did not come across this as a cause at all.

[roosterk0031]

Never would have thought about rust expansion collapsing the hose, makes since cause I had 2 fail at basically the same time.

[drmiller100]

mid 60's vw bugs have brake lines which come apart. i've seen them where they act like a one way valve

[Frank Lee]

This modern hose has quite the generous wall thickness and several concentric layers of reinforcement. The I.D. is so very small that it doesn't take much external crimping deflection to close it off. Before I cut it up I sat there examining it and would never have guessed that bracket was bearing down on that hose enough to crimp it shut- it simply didn't appear to be that bad.

I've messed around with so many old '60s VWs over the years and can't count them all. I don't recall having a bad hose on any of them but I don't doubt that it happened.

[gone-ot]

...is this ( above ↑ ) a newbie or spam?

...Vietnamese?

[some_other_dave]

Originally Posted by Frank Lee

Almost everything that isn't a heavy duty truck has plastic pistons.

That is certainly different from the early 90s! The pistons in the calipers of my CRX were metal. I thought the pistons in Da Wife's 2000 M-B were metal as well, but I could be wrong on that.

It would certainly eliminate the pistons rusting, which was one possible failure mode in some of the old cars.

-soD

[Frank Lee]

All my '80s and '90s Fords have 'em.

GoldWing has metal pistons but it would be far better off with plastic! They corrode like nobody's business.

[roosterk0031]

Only plastic pistons I've ever seen was on a Honda xr600 dirt bike front dual piston caliper. First one popped out really easy, finally figured out I had to put it back in and pop them at the same time using the brake fluid, with a c-clamp and pads to let them out together.

Never on a GM that I've owned and noticed, but just assumed they were always metal.