Stainless Brake Lines - Which Ones?

[CCM911]

It has been about 12 or so years since I last replaced my brake lines, so I went in to the Pelican catalog to do some shopping. I came across a plastic coated set for $109.00. Then, for some reason, I clicked forward through the pages, and came upon another set for $67.00, which were not rubber coated. Both were DOT approved. Since the ones I use now are not plastic coated, I plan to go for the $67.00 non-coated version.

Am I missing something here?

[TheSt|G]

Originally Posted by CCM911

It has been about 12 or so years since I last replaced my brake lines, so I went in to the Pelican catalog to do some shopping. I came across a plastic coated set for $109.00. Then, for some reason, I clicked forward through the pages, and came upon another set for $67.00, which were not rubber coated. Both were DOT approved. Since the ones I use now are not plastic coated, I plan to go for the $67.00 non-coated version.

Am I missing something here?

Aren't the DOT approved ones technically worse? I don't remember the specifics at this point, but the generally idea was that connector was inferior I think? Been a long time since I read about it...

Related thread:
Stainless Brake Lines

Seems like stock rubber might be the best bet...

[CCM911]

Thanks, Stig!

A lot of BS on the referenced thread. I have used the Stainless lines for more than 12 years, including 5 years of very hard track use, and they are fine.

[jchris]

When I got my stainless hoses, the local shop I purchased them from said he didn't like the coated because the coating eventually fails and ends up looking worse than normal wear. Anyway mine look good and perform welll with three years on them. My VW driving buddy was shocked at the responsiveness of my brakes. Though compared to a 71 bus......

[chris_seven]

Any brake hose used on road cars have to meet the requirements of FMVSS 106 which may have been updated and changed number.

On of the requirements is that all fittings must be swaged or crimped.

Re-useable Aeroquip fittings are therefore not permitted and their use could invalidate insurance in the event of a big enough accident to cause crash investigators to look at the car in great depth.

I do realise this is very, very unlikely but could happen.

I have to say that I have never liked re-useable fittings as I have seen too many failures due to poor assembly.

Apart from limits on flexibility and burst strength - all of which PFTE hose more than passes - DOT Approved hose assemblies must pass a 'whip' test and there has been some concern about PTFE hose and this test mechanism.

Most DOT approved hose has a plastic component around the fitting to increase the radius of any bending that occurs during the whip test and enables them to pass this part of the test successfully.

I don't think that non DOT hose with re-useable fittings are technically worse as the swage fittings are very reliable and work well and are the standard for virtually all high pressure hydraulic machinery.

[TheSt|G]

Originally Posted by CCM911

Thanks, Stig!

A lot of BS on the referenced thread. I have used the Stainless lines for more than 12 years, including 5 years of very hard track use, and they are fine.

I don't disagree. Lines have always been one of those gray areas to me, where I've never seen a definitive case one way or the other as to what is best and why. In the end, I usually use the factory option as it has the least "risk".

[KTL]

The theory behind the coated braided stainless lines, as I understand it, is the coating prevents fine debris from invading the braid. When the braid flexes it can work the debris into the hose itself and cause leakage.

[Quicksilver]

Originally Posted by KTL

The theory behind the coated braided stainless lines, as I understand it, is the coating prevents fine debris from invading the braid. When the braid flexes it can work the debris into the hose itself and cause leakage.

It is the opposite. The plastic coating is to keep the stainless braid from acting as a saw blade and grinding/cutting its way through whatever it is allowed to vibrate against. Hopefully you have routed the lines so they can't contact anything through their whole range of travel.

--------
Here is the whole deal about DOT stainless lines vs aviation style (aeroquip) style lines.

DOT requires that the lines be swaged (crimped) to the connector so there is no possible way it can be tampered with to allow failure. Swaging is not the best way to make a connection with the teflon lined hose. It doesn't have the elasticity like rubber that works well with swaging. The manufacturers have put a lot of work into coming up with a way to make it work.

Aviation type ends are what was actually designed to work correctly with this type of hose. It is MUCH more reliable if terminated correctly...
... But then humans get involved. There is no control over the ability of the installer to correctly work with the aircraft style hose ends so there is a much higher chance that the installer will screw it up. And an inspector can't tell.
Lots of simple ways to mess it up:
- If you cut the hose incorrectly you can damage the internal teflon hose.
- It you cut it incorrectly you can mess up the end of the steel braid.
- If you don't get the hose inserted correctly in the hose end it won't seal correctly.
- As you are tightening the hose end the hose can back out.
- You can mismatch the hose ends with the type of hose.
- You can over tighten the hose ends.
- You can use some sort of thread sealant, tape or goo. (NEVER use any sealant on flare fittings!)

All of these failures can't be seen from the outside so you have no way to tell if it has been mucked up other then if you did it yourself and you have experience doing it correctly. Plus if someone comes along after the fact they can screw it up and that can't be detected.

And as pointed out: If an insurance company notices them after an accident they will use ANY excuse to weasel out of a claim even if the brakes didn't fail.

Do with it what'cha like!

[CCM911]

Man, a lot of good knowledge here.

Thanks so much for the replies.

[luyckxglen]

Promoties / Traxracing.com for all ur costum brake lines or even oil lines.
These guys produce it all, every size you want! every fitting..

[Canada Kev]

Originally Posted by KTL

The theory behind the coated braided stainless lines, as I understand it, is the coating prevents fine debris from invading the braid. When the braid flexes it can work the debris into the hose itself and cause leakage.

Originally Posted by Quicksilver

It is the opposite. The plastic coating is to keep the stainless braid from acting as a saw blade and grinding/cutting its way through whatever it is allowed to vibrate against. Hopefully you have routed the lines so they can't contact anything through their whole range of travel.

One can also use some spiral wrap over the stainless to stop abrasion if it could possibly make contact. That's what I used to do back in the day on motorcycle braided stainless brake hoses.

Stuff like this:

[Jack Stands]

I was told by some knowledgable folks that you're better off with the factory brake lines, not the stainless ones. In racing, where these are inspected and replaced often, they are OK, but not in a street car. As one who did have a braided hose once fail on one of my cars, I'm switching back to the rubber ones.

[KTL]

I'd heard on a few occasions that the fine debris can work its way into the braid and then it can compromise the hose. But I find that to be pretty unlikely since the braid is quite dense. Also have heard that the braid can hide the signs of a failing hose, like general cracking of the rubber material. That I believe.

Thanks for the clarification. And I hear what you're saying about all the points regarding reuseable hose end pitfalls. Having built a handful of my own lines (not the teflon style, yet) I completely agree there's a lot of potential for failure based on the dude assembling the hose.

No disagreement from me on the ability of stainless braid to cut like a saw. It is VERY effective at rubbing thru panels and anything else it contacts.

That said the teflon lined hoses are a much more durable hose for high pressure use like brakes. The teflon liner eliminates the potential for hose swell that is common in "plain" rubber hoses. And they do have a greater resistance to expansion under high pressures. However the pretty braid seems to make people think they are indestructible and a lifetime installation. Just like regular hose, they get stiff and need replacement.

Brake flex hoses in general are a piece of the brake system that so many people overlook in terms of maintenance. Most people pretty much never think about replacing them. A friend recently had a sticking caliper on his '98 F150 truck. We traced the problem to an internally swollen flex hose (hose condition allows master cyl. pressure to seek the caliper but does not allow the pressure to quickly release when you get off the brake pedal) and he was amazed that something like that could happen.

[KTL]

I knew I had seen some mention of the plastic coating being protective of the braid, as well as it protecting other stuff that may come in contact with the braid- see Abrasion Resistant Coating/Sheath subsection

Essex - Stainless Steel Brake Lines

"All Spiegler Stainless Steel Lines come with an abrasion resistant coating. On the standard parts (non-custom colors), that coating is clear so you’re able to see the underlying stainless weave. The abrasion resistant coating prevents the line from snagging, protects the stainless weave from debris, and also allows the line to slide smoothly through any required retainers or brackets for a given application"

Whether its an actual issue or not, I don't know. Just sayin' so it doesn't look like I make this stuff up as I go....

[CCM911]

LOL, Kevin.

Well guys, I went for the $67 set of lines. I figured if the last set lasted over ten years, they are good enough for me.

And in the interest of full disclosure, my lines are still fine. I am just replacing them as a matter of long term maintenance.