Lifespan of Stainless Steel Brake Lines?

[IAN]

Anyone have any thoughts on this?

10 years?

Thanks.

[911pcars]

Typically teflon lined. I would think catastrophic failure or leakage at the fittings are a sure sign. YMMV. I knock on wood; mine are still intact after 12 years. I must rely on awesome reflexes and dual brake circuit.

Sherwood

[IROC]

Originally Posted by 911pcars

I knock on wood; mine are still intact after 12 years.

Mine are slightly older than that.

[Trackrash]

One of the local gurus says seven years on the DOT type. It seems that the abrasion of the stainless wire on the inner Teflon may be the culprit?

[RWebb]

the problem is that you never know when and cannot find out - one reason I like rubber hoses

[Joe Bob]

Depends if they are DOT approved or for racing only. The race crowd swaps them out every season. I prefer the OEM rubber, less catastrohic documented failures. I used one to relocate the oil gauge on my Harley......bling bling doesn't always mean better.

I use the s/s braided line on my oil coolers....but I have a gauge that will warn me of a leak. Not so on my brakes.....

[Bill Verburg]

Originally Posted by Joe Bob

Depends if they are DOT approved or for racing only. The race crowd swaps them out every season. I prefer the OEM rubber, less catastrohic documented failures. I used one to relocate the oil gauge on my Harley......bling bling doesn't always mean better.

I use the s/s braided line on my oil coolers....but I have a gauge that will warn me of a leak. Not so on my brakes.....

If a manufacturer claims their SS lines are “DOT compliant”, it means that their SS lines have passed all FMVSS106 requirements, and they have submitted the test data to the government for official certification. This does not mean they are acceptable for use on your car, but it does mean they pass the government minimum standards.

That said quality lines like Goodrich and Technifit and Earls are DoT compliant and you won't go wrong using them.

I like the lines w/ an outer cover that will keep dirt and grit out of the ss sheath.

[Grady Clay]

Actually, the OE rubber hoses are better for braking at-the-limit.

The OEM rubber/fabric hose has a bit more ‘give’.
As the tire rotates, the brake friction is not perfectly consistent as the rotor passes under the pads.
The little bit of ‘give’ reduces the tendency to stop (lock) the rotor at a high-friction point.
This exact same is true with the more inconsistent friction between the tire and the road.
Here, a few grains of sand can reduce the friction in one small place.

You can actually feel this when braking hard where the tires are turning at slightly less than road speed.
This is where your foot is acting like ABS vibrations.
The slight ‘give’ helps.


The reason for SS covered hoses is (supposedly) to protect from road debris damage.

The problem with SS hoses is sand and dirt gets between the steel and the (very soft) Teflon.
Over time (1 year and less) the grit gets embedded in the Teflon pressure tube.
I have cut off the SS braid and it is ugly.

That said, most hose assembly failures occur at the connection between the flex hose and the fitting.

Ten-year life for rubber hoses is appropriate. Five-year is better.
One-year is appropriate for SS/Teflon.


I use DOT OEM rubber on my street cars and racer.

2¢

Best,
Grady

[Joe Bob]

OK....GRADY....where did you get the "2¢" key stroke?

[Neel]

Interesting read, Grady.. I've heard several arguments for both sides.. Your's makes good sense to me!! Thanks!!

[Kevin Stewart]

the biggest problem i have had is the line frays(spelling?) inside and holds pressure one direction or the other, I have had it happen with both styles, Kevin

[Kevin Stewart]

o and one more problem i have had with braided lines is kinks, you jack the car up it looks perfect when you take the wheel off, let the car back on the ground and it kinks shutting off brake fluid. I no longer jack the car up to check anything before i head to the track, i put it on railway ties and crawl under to inspect everything, Kevin

[HarryD]

I have installed miles of teflon tubing for my former employer. The stuff does not like to be kinked and once kinked, it is junk (catatrophic failure point). It was very painful ($10/ft plus labor) to throw away 1,000 feet of ultra high purity teflon tube due to a kink (I was not permitted to have any intermediate fittings between the supply and the point of use).

[Grady Clay]

Originally Posted by Neel

Interesting read, Grady.. I've heard several arguments for both sides.. Your's makes good sense to me!! Thanks!!

I have driven race cars with ‘perfect’ hard brakes.
They are very sensitive to locking up the tires.

Of course, cars with ‘spongy’ brakes or ones that tend to ‘pump up’ are disconcerting to drive as these are common indicators of impending failure.
I don’t tend to use the braking at-the-limit capacity of a car like this even though it may be capable.
Chicken me – and these tend to be something expensive not owned by me.

Originally Posted by Kevin Stewart

the biggest problem i have had is the line frays(spelling?) inside and holds pressure one direction or the other, I have had it happen with both styles, Kevin

With OEM rubber hoses, this is a very-old-age problem.
This is particularly true of cars that seldom had the brake fluid changed.
The hoses should be replaced long before this happens.
This is the primary reason for my 5-10 year life recommendation.

With SS/Teflon, this is a manufacturing defect.

Originally Posted by Kevin Stewart

o and one more problem i have had with braided lines is kinks, you jack the car up it looks perfect when you take the wheel off, let the car back on the ground and it kinks shutting off brake fluid. I no longer jack the car up to check anything before i head to the track, i put it on railway ties and crawl under to inspect everything, Kevin

If this happens, I suspect incorrect mounting of the hose.
Possibly the hose is too short.
The ‘S’ bend of the hose should accommodate the complete suspension movement without putting a ‘twist’ in the hose.
You should install the hose (tighten the last fitting) with the suspension in ‘normal’ operating position.

I agree, if ‘kinked’ it will fail and should be replaced ASAP.

Originally Posted by Joe Bob

OK....GRADY....where did you get the "2¢" key stroke?

I compose all my posts in MS Word.
I have my ‘Custom Porsche Spell-Check’ in force.
It also gives me one more opportunity to edit my post.

The ¢ are from the MS Word ‘Insert-Symbols’ menu.
A surprising number transfer to vBulletin.
€, ₤, ü, ±, Ø, Δ, ë, é, X² and many more.
I haven’t figured out how to use superscript, subscript and strikeover but there seems to be a way.
I have seen these on other forums powered by vBulletin.
This is where we should help Wayne with a ‘how-to’ link (including Search).

Best,
Grady

[Bill Verburg]

Originally Posted by Grady Clay

I have driven race cars with ‘perfect’ hard brakes.
They are very sensitive to locking up the tires.

.....
Best,
Grady

SS covered Teflon merely take a tiny amount of inefficiency from the process of applying the brakes, in and of them selves they will not measurably add to touchiness or sensitivity. Sensitivity issues are far more commonly caused by inappropriate pads and m/c size

rubber lines will expand a little bit when brakes are applied there can easily be 100bar of pressure in them, teflon merely expands a little less.

Folks call them ss lines but they are really ss covered teflon lines.

the ss sheath is a cover to mechanically protect the lines from debris, on rubber lines you will often see a spring like sheath that serves the same function

Grady is correct in that the ss sheath, like cocco mats, is porous to dirt and grit which will collect inside the ss sheath and abrade the inner teflon line. To keep the grit out there needs to be another outer layer of plastic sealed at the ends.

properly selected and installed ss or rubber lines will not kink or stretch enough to loosen them.

yes, rubber lines will swell internally after years of use and this will be exacerbated by infrequent fluid changes, I agree that for most users oem rubber is the way to go though.