SS Brake Hose... Racing vs DOT Options

[DBCooper]

I apologize for beating this to death, but here we go. (IMG:style_emoticons/default/dead horse.gif)

I’m honestly intrigued that the agency in charge would let such a dangerous product onto the market. I’ve never had a problem with those hoses, but it seems I might be the only one who hasn’t. Not to even get into the performance motorcycles that come from the factory with braided hose. This genuinely surprises me, because I can’t imagine why insurance companies and product liability lawyers haven’t had a field day with it. A government agency being inept? I have no problem believing that, but overlooked by shady lawyers? I’d think those jackals could sniff out carrion anywhere.

Anyway I had to find out more, so I looked up the NHTSA TP-106-10 standard and had a read, (see it HERE). This standard was issued in April of this year, and sets the testing and performance standards for brake hoses. The list of tests is pretty impressive and seems complete, including:

LABELING INSPECTION
12.A.2. CONSTRICTION TEST
12.A.3. EXPANSION TEST
12.A.4. BURST STRENGTH TEST
12.A.5. WHIP TEST
12.A.6. TENSILE STRENGTH TEST
12.A.7. LOW TEMPERATURE RESISTANCE TEST
12.A.8. END FITTING CORROSION TEST
12.A.9. OZONE RESISTANCE TEST
12.A.10. WATER ABSORPTION TEST)
12.A.11. BRAKE FLUID COMPATIBILITY TEST
12.A.12. HIGH TEMPERATURE IMPULSE TEST
12.A.13. DYNAMIC OZONE TEST)
12.A.14. TRACER CORD IDENTIFICATION

All these tests refer directly back to SAE, ASTM and other standards bodies requirements for testing, materials, and performance. As a quick summary the two most compelling problems mentioned in our discussions would covered by the tensile and whip tests. These tests are conducted with pressurized hoses:

Tensile Test - ( A ) Conduct the slow pull test by applying tension at a rate of 1" per minute. The assemblies shall withstand a minimum pull of 325 lbs. ( B ) Conduct the fast pull test by applying tension at a rate of 2" per minute. The assemblies shall withstand a minimum pull of 370 lbs.

Whip Test – This is as the description implies, whipping the hose back and forth. “The time duration for the whip test shall be 35 hours at a machine speed of 780 to 800 rpm.”

If you read the full text these aren’t sloppy, easy tests. I could imagine that a brake hose that was too short for the application would fail if yanked lock-to-lock between the hard line mount and your caliper, but other than that, which is misuse, I don’t see anything in the test being insufficient for the application. Same with the whip test. That test, by the way, is what separates the “DOT” hoses from “race” hoses. To pass the Whip Test the hose manufacturers install a rubber or plastic collar from the fitting up through the first two inches of the braided part of the hose. That gives that section of hose some support so it doesn’t go into shear against the fitting. No plastic reinforcement means “race” hose.

I know more now, but still have no idea how so many brakes could have catastrophic failures on public highways without provoking a firestorm of lawsuits. That’s OK, I guess, there are a lot of things I don’t understand.

I did read something interesting that I didn’t know, about the metric system. Did you know we’re on it? From the introduction to this standard:

“Section 5164 of the Omnibus Trade and Competitiveness Act (Pub. L. 100-418) establishes that the metric system of measurement is the preferred system of weights and measures for trade and commerce in the United States.”

I wasn't aware of that, so it was very interesting news. Especially since every measurement in this standard was exclusively in Imperial values.

[Spoke]

I had braided hoses on the front of my car when I 5-lugged it. They were very stiff. When checking for left-right freedom of the struts before connecting the tie rods, I noticed the stiff braided hoses caused the end of the hard lines on the body to flex.

Fearing the hard lines may fatigue from the flexing, I replaced with standard rubber hoses. The hard lines don't flex now.

[jmill]

With performance motorcycles you'll notice that the hose is long. It also goes through a small range of motion. It has a very small chance of reaching its elastic limit.

Take that same hose and shorten it up by 3x. Then put it through 3x the range of motion. Like your cars front brake line. There is a much higher chance of it reaching its limit.

If I have some SS hose at the house I'll do a little show and tell.

[jmill]

One other thought. The front brake reservoir is attached to the handle bars. The only motion the line would see is vibration and the up and down movement of the front wheel.

The rear brake is mounted to the frame and is operated by your right foot. The only motion that line would see is vibration and the up and down motion of the rear tire.

An automotive line sees right, left, up, down and vibration all at the same time.

[So.Cal.914]

One other thought. The front brake reservoir is attached to the handle bars. The only motion the line would see is vibration and the up and down movement of the front wheel.

The rear brake is mounted to the frame and is operated by your right foot. The only motion that line would see is vibration and the up and down motion of the rear tire.

An automotive line sees right, left, up, down and vibration all at the same time.

In the front. (IMG:style_emoticons/default/smile.gif)

[jmill]

You got me there. (IMG:style_emoticons/default/biggrin.gif)

BTW - Your avitar is outstanding.

OK, here's the show and tell I talked about. This is high quality aircraft stuff. It blows the doors off of any automotive line.

The line on the left was cut using a high speed grinder. You'll notice it's nice and round. The line on the right was cut using very sharp diagonal cutters. You can see how the line is tweaked and no longer round. The line was stressed beyond its elastic limit. Kinking the line would do the same thing. The line would be weakened at that spot. Continued movement will eventually cause the line to fail.

[Wilhelm]

So..................... Does anyone make a SS covered rubber line? Bling and saftey.

[DBCooper]

Sorry, but how is that relevant? You've deformed one with side cutters, but how would that ever happen in automotive use? No automotive hose that is the correct length will be put into a position that it can be flexed to the point that it "kinks" the way you indicate. If it's possible to do that with the hoses on your car it means they're too short, and that would be misuse. You cut the other with a high speed wheel, the way it should be cut. I really don't understand the comparison or your point.

If you have the correct length brake hose it should never be put into the position where it can be extended so much that it's stressed. Certainly never stressed longitudinally as much as the NHTSA tensile test. The only thing a correct length hose should ever see in automotive use is movement, and NHTSA "whip" test is intended to be an extreme case of exactly that. Both braided stainless hoses and standard rubber hoses pass that test.

Do you know of any formal test data that indicates that teflon hose, covered or not, has flex performance that's inferior to rubber? If so, how much? That would be relevant.

By the way, the NHTSA test mentioned above was released in April of this year, 2008. So it's a brand new standard. And further the NHTSA database (it's on their website) shows no investigations of any brake hoses from failures in use. IE no complaints. Zero. So if you've had a catastrophic brake failure I'd request that you do every automotive enthusiast a favor and register that with the NHSTB so nobody innocent dies. Their complaint number is (888) 327-4236.

[jmill]

The purpose of the picture was to show that the hose isn't as resilient as rubber. We've all cut rubber hose before. You dont have to baby it with a high speed grinder to avoid damaging it. Cut it with an axe and the end will still be round. I believed that was relevent to the discussion.

Folks that have experience working with SS hose and those that have had failures are sharing their experiences with you. Take it or leave it. If you think they're the best thing since sliced bread go for it.

I've run them on race cars and had good luck with them. The pros outweighed the cons. When driving a car on the ragged edge every extra bit helps. I personally wouldn't run them on a street car. The line is inferior to rubber in the resilience department.

It seems odd to me that in all those DOT tests there isn't one that actually tests the line on a car. Did I miss those? (IMG:style_emoticons/default/confused24.gif)

[Slick914]

Didn't mean to bring up a sore subject. (IMG:style_emoticons/default/huh.gif)

Now that you all have me scared about the SS DOT lines I was going to use, I'll trade them for a set of rubber ones. (IMG:style_emoticons/default/biggrin.gif)

[sean_v8_914]

I did not know/think about many of these valid points. flying rocks, road debris, dirt inbeded in the braid...I can see why they are less durable.

the pros: stiffer pedal "feel" and bling.

[DBCooper]

First off I'm not trying to be argumentative. Please read all of this before you get pissed off.

The purpose of the picture was to show that the hose isn't as resilient as rubber. We've all cut rubber hose before. You dont have to baby it with a high speed grinder to avoid damaging it. Cut it with an axe and the end will still be round. I believed that was relevent to the discussion.

Relevant how? We're talking about complete manufactured assemblies, not hose cut at home in the garage. Couldn't what you're showing indicate a hose material that's actually more flexible, not less, since it's being held in that oval shape by the braided steel reinforcement that was deformed by the side cutters? A steel cover that rubber hose doesn't have? In the actual science of the matter teflon hose (PTFE anyway) can have almost infinite flexing without affecting the material. As long as it's not overstressed by kinking, which is the big proviso. It's also pretty much impervious to aging, heat (great improvement over rubber), and chemical degradation, meaning any type of brake fluid, even the really nasty new synthetics. In that regard it's far better than a rubber hose, which in fact isn't 'rubber' at all, but also a synthetic. The only time that any brake hose should kink is if it's misused, like letting a caliper dangle from it without support. But that kind of misuse means any hose should be discarded, whether rubber or teflon.

Folks that have experience working with SS hose and those that have had failures are sharing their experiences with you. Take it or leave it. If you think they're the best thing since sliced bread go for it.

You assume I have no experience, which is not correct. But I appreciate your remarks, really. I'm probably a bit oversensitive because I'm in the safety business and also member of a committee that writes the safety standards for my industry. Not automotive and not hoses, but there still shouldn't be any product on the market that produces catastrophic failures at the rate that's being described here. I personally suspect that these failed hoses are because of some type of misuse somewhere, the hose has been kinked somewhere in the sales channel, packaging, in installation, or whatever. But that's only a suspicion on my part, and there's no way to know for sure unless someone is alerted and investigates. So please do me a favor. The next time you have one that breaks call that NHTSA number and report it to someone who can do something about it.

It seems odd to me that in all those DOT tests there isn't one that actually tests the line on a car. Did I miss those? (IMG:style_emoticons/default/confused24.gif)

That wouldn't be relevant. Laboratory tests only simulate real-world use, but in an accelerated, controllable and repeatable manner, so when I do the exact same test in my laboratory I'll get the same results that you did in yours. That's the laboratory standards testing, where the tests were developed from failures that had been seen in the field. But of course that depends on the regulators getting data from the field to become aware that there ARE problems so they can investigate and find the cause.

I'm not trying to be snide here, not at all. As I said before there are no current reports of brake line failures of any type in the NHTSA database, so if you're seeing repeated failures of brake hoses then for God's sake report them. It's in everybody's interest.

[Mark Henry]

First off I'm not trying to be argumentative. Please read all of this before you get pissed off.

Sorry but i don't have time to read all that shiiiiiiiit....um, stuff! (IMG:style_emoticons/default/rolleyes.gif)

Bud, do what ever you like....just you've had the advice of a few long term wrenches, doesn't matter how much "research" you throw at us we will still be using rubber lines.

'nuff said (IMG:style_emoticons/default/dry.gif)

[SirAndy]

just you've had the advice of a few long term wrenches, doesn't matter how much "research" you throw at us we will still be using rubber lines.

(IMG:style_emoticons/default/agree.gif)

The factory rubber hoses had to go through some extensive testing to pass the TÜV approval.

That's good enough for me. No need to pay extra for some "bling" ...
(IMG:style_emoticons/default/rolleyes.gif) Andy

[jmill]

The steel braid isn't holding the hose in that position. After the braid is cut it doesn't hold anything together. That's the reason for the tape on the line cut by the grinder. It holds the braid so it doesn't unravel. The braid is like a Chinese finger puzzle. I could peal the braid back to show you the tweaked teflon but I'd poke my finger 150 times just so you could say it's irrelevant.

A complete assembly is only as strong as its weakest part. The picture shows the weakest part. The inner teflon. The fact that you don't find the picture relevant baffles me.

Any material can flex infinitely as long as it's not flexed past its elastic limit. The simple truth is that teflon reaches its elastic limit before the stock line. I could cut a stock line with a diagonal cutters and show you it's still round. But again I'm afraid you'd feel it was irrelevant.

How is installing the line on the car irrelevant. How does the DOT check the hose for proper length and measure bend angles that might be encountered? The labratory tests are irrelevant.

I've worked with engineers for many years. They design it and I build it. I've tried to explain this simple fact to them many times. Just because it looks good on paper doesn't mean it's going to work in real life.

I hate to say my patience is exhausted. I suppose yours is too. How about we agree to disagree.

[DBCooper]

Both types of hose are TUV certified.

If you want to fix the problem call (888) 327-4236 the next time you see a failure. If you don't give a shit then don't call. No one ever HAS called, so I guess it's not really that much of a problem anyway.

[SirAndy]

Both types of hose are TUV certified.

I've seen plenty of braided lines sold here in the US that aren't ...
(IMG:style_emoticons/default/shades.gif) Andy

[ztbell]

(IMG:style_emoticons/default/blowup.gif) Stay with the D.O.T. approved SS lines.
I also had a near miss with the racing version...ZB

[Cap'n Krusty]

Please correct me if I'm wrong, but it appears to me that the ONLY difference between the currently available "racing" SS brake lines and the "DOT" lines is the sticker, certifying that the product so labeled has been tested in accordance with the DOT's specs and procedures. Costs money to do that, and the end user is gonna pick that up. If they can sell 'em to racers, that not-inconsiderable cost can be avoided, and their per-piece profit will be higher.

The Cap'n

[hcdmueller]

Both types of hose are TUV certified.

I've seen plenty of braided lines sold here in the US that aren't ...
(IMG:style_emoticons/default/shades.gif) Andy

(IMG:style_emoticons/default/agree.gif)

There are a lot of products I can't use on my car over here because it won't pass inspection. In fact I failed the first time out because of the DOT braided lines. I get some wiggle room because I register on the military system but they still have some strict safety standards. They have to give us some leeway because most american cars won't pass the TUV inspection.