Cut open a clogged brake hose

[ctechbob]

Rust jacking. Same thing can happen to brake pads in that environment where the rust grows underneath the pad material and pops it loose from the backing plate. I'd think something along the lines of Fluid Film would be fine, although as stated above, in that climate they really should be on the replacement parts list.

 

[Jetronic]

And? A better, corrosion resistant material may last indefinitely.

Yes but the OEM has no interest in making the brake line more expensive for something that will outlast the usefull life of the car anyway. Usefull life from thew point of view of the mamufacturer...

 

[Snagglefoot]

Chalk this up to the types of things you have to pay attention to on a 20 year old car in the northern climates. I just sent one to the wreckers. The coil spring on the front strut busted and pierced the tire. Coil springs, brake lines, brake hose fittings, frame rust, bolts on suspension components. They all need extra attention.

 

[Trav]

I'd say this is precisely the reason that Mercedes Benz calls for "Brake Fluid Replacement" every 20,000 miles.
(Rolls Royce calls for brake hose replacement every 100,000 miles)
Another option would be to switch to silicone brake fluid early on, but that's not normally called for by the manufacturer.

No DOT 5 in ABS systems.

 

[JeffKeryk]

We don't know much about rust in sunny CA, but I have 2 kinda older vehicles, the '01 Tundra and '06 TSX. Both have 200K on the clock.
This post makes me consider brake flex line replacement. The fluid does get serviced...

 

[Astro14]

Thank you for digging into your problem. I knew that brake hoses would fail, and become “check valves”, but seeing the mechanism was very informative.

Cheers!

 

[Astro14]

Excellent cut and post. Maybe brake lines should should be on a replacement schedule.

Mine are. 10 years. I reckon that’s long enough for a rubber part whose failure can cause a serious crash.

 

[wpod]

That is a some what common failure with all types of hydraulic lines. I have even had garden hoses fail in such a way.

 

[wpod]

Mine are. 10 years. I reckon that’s long enough for a rubber part whose failure can cause a serious crash.

My neighbor a retired AA pilot was scrupulious in the maintenance of his vehicles .... Must be a pilot thing

 

[Trav]

My neighbor a retired AA pilot was scrupulious in the maintenance of his vehicles .... Must be a pilot thing

Most TÜV inspectors are not pleased with 6 year old hoses. Most will not fail it but once in a while you run across one that will and rightfully so in most areas IMO, somewhere like the south west may go longer.

 

[Sam_Julier]

Thanks for documentation. I changed the brake hoses in both 240s when I took procession. Will now put them on a 10 year replacement schedule.

 

[porterdog]

Props OP, I've had the same issue before (no gravity bleeding) but never knew why. Excellent work.

As I've said elsewhere, I use CorrosionX on the undersides of my vehicles and have been doing so since ~2011 or so. It very definitely creeps along metallic surfaces, so I love it for things like stranded battery or ground cables, protecting hardlines where they go through body clips, and brake line fittings including both the hard-to-softline transitions (which suck when they get locked up with rust) and the bracketry you're describing. Mostly I'd have done those to ensure I could dismount then when needed but wetting the steel collar with CX would likely have helped here.

 

[Falcon_LS]

We don't know much about rust in sunny CA, but I have 2 kinda older vehicles, the '01 Tundra and '06 TSX. Both have 200K on the clock.
This post makes me consider brake flex line replacement. The fluid does get serviced...

Most my vehicles have braided stainless steel hoses, but the one vehicle that doesn't gets new brake hoses every 3 years. I use DOT 4 Plus or DOT 5.1, and tend to replace the fluid every 6 months regardless of mileage. Goes in clear yellow, comes out looking more like olive oil in 6 months. Better out than in.

 

[Rand]

Hey thanks for posting good writeup, some decent photos to go with it.
2 thumbs up

 

[supton]

Thanks for cutting and posting. Good info.

 

[LeakySeals]

Wondering if bleeding the brakes more often and not pushing fluid back in to the caliper during a brake job would help

 

[supton]

Wondering if bleeding the brakes more often and not pushing fluid back in to the caliper during a brake job would help

Not sure--personal conjuncture here--I wonder if moisture can slowly diffuse through the rubber to attack the line. OP wondered it was from moisture making its way in from around the fitting itself. Thus the brake fluid itself wasn't the source.

Hard to say. Makes me wonder about the 20 year old lines I have on one car though.

 

[GoToGuy_Ron]

This is a problem any vehicle in Rusty midwest to east coast could experience. As the root cause was discovered. The corrosion started at the top or opening of the metal crimp. Then proceeded to work it's magic chemical process. It grew and continued to work it's way down between hose and metal sleeve. In doing so functioning in the same way a plant's root can split a rock. The corrosion grew and the pressure caused the rubber hose collapse under pressure creating a " check / restrictor valve " of sorts as stated in the differential braking. A good tip: Brake Fluid loves water, the highest concentration will be at the lowest point in brake fluid system. Rusted corroded brake cylinders, disc or drum. If doing a brake job get a extra Quart or two of brake fluid and flush bleed all the old fluid. Guaranteed it make your seals happier and maybe put off replacing master cylinder brake for little longer service interval.

 

[Dave9]

And? A better, corrosion resistant material may last indefinitely.

Wrong way to look at it. The hose should be replaced every 10-15 years no matter what, as the hose itself can fail instead of the fittings. No real need to do fluid film or similar, they'll just need replaced again in 10-15 years given same environment.

Now the question is, what about the hard lines? They are due for replacement too, if they are factory bare metal rather than coated, unless some prior rust-preventative measure was taken on them to mitigate rust.

In this case, a more corrosion resistant material like CuNi line does make sense, because it's also easier to work with than steel, let alone stainless, and can be expected to outlast the 4 soft lines.

This has nothing to do with this failure and in a winter saltwater environment, uncoated steel line is going to rust through from the outside before the inside. Do change the fluid if you're getting brake sponginess due to moisture, but it's not the kind of ticking time bomb many people imply, unless you're pushing your brakes really hard.

 

[sdowney717]

Might on a new line use some RTV and seal the crimped metal ends where they meet the rubber hose.
And old line, might use marine grease on it, but how many would do any of that. Where I live, not a snow and salt problem.

I uncrimped an ATF line where it meets the rubber and there was significant rust under the crimp coming from the crimp. This is on a 2005 Ram truck with 48RE. Reason I did this, the OEM tube has a nice bead for reuse with a rubber hose and a hose clamp