New pads, old rotors?

[Eye of the Tiger]

Why would your lines be empty during a flush? You're continually cycling fluid through the system till you get fresh fluid coming out the ends. At no point should you have empty lines during a flush...

It's good to air everything out and let it breathe before you fill it up again.

[Byteme]

Hmm okay let's take a poll.

Who here has SS lines on a car that used to have rubber?

I do! And I notice a difference. My brake feel is fantastic.

I used them on my first E-type.  Zero difference noted.

[Rupert]

Hmm okay let's take a poll.

Who here has SS lines on a car that used to have rubber?

I do! And I notice a difference. My brake feel is fantastic.

You'll understand if I wait for a real test before I draw my conclusions, won't you?

[CaminoRacer]

You'll understand if I wait for a real test before I draw my conclusions, won't you?

Not my fault if you are unwilling to listen to the scientific reasonings why a stiffer line makes for a less squishy pedal. There's no way to "test" brake feel other than listen to people who have upgraded.

[Cookie Monster]

Not my fault if you are unwilling to listen to the scientific reasonings why a stiffer line makes for a less squishy pedal. There's no way to "test" brake feel other than listen to people who have upgraded.

OK...

Also: you don't need to change to a higher temp fluid for the street. Lol. Or lol. SS lines also a waste. I have them on the E46 and don't have them on the 1M. No noticeable change. On the track, for street use no way that's necessary.

Braided stainless lines do stretch less than typical rubber lines, and that can give you a bit more feel.  I think they are more noticeable on something like a motorcycle than a car that has power brakes and not likely something I'd invest in for a car.

I used them on my first E-type.  Zero difference noted.

Again, on a track car where you're doing repeated hard, fast stops with little cooldown in between, I'd upgrade to SS lines just to make sure everything is track-capable. On a daily driven Civic that's not likely to see the track? What's the point?

[CaminoRacer]

SS lines don't help with heat.

Lots of reasons to upgrade, as seen on the link I posted. Stronger, more durable, may help with brake pedal squishiness (depending on what you started with).

I'm surprised a motorcycle guy is against them, since practically every bike review I've read in the past month has said "could use SS to improve feel".

[Cookie Monster]

SS lines don't help with heat.

Lots of reasons to upgrade, as seen on the link I posted. Stronger, more durable, may help with brake pedal squishiness (depending on what you started with).

I'm surprised a motorcycle guy is against them, since practically every bike review I've read in the past month has said "could use SS to improve feel".

If you're referring to me as the motorcycle guy, I can barely ride them.

I swapped the front brake lines for SS on my bike and didn't really notice a difference, though. I don't track my bikes so for DD use I haven't noticed a difference.

[CaminoRacer]

http://www.superstreetonline.com/how-to/wheels-tires/modp-0909-brake-lines-upgrade/

When testing volumetric expansion, Goodridge found that standard OE-type rubber brake hose expanded by 0.136 cc/ft at 1,000 psi, 0.150 cc/ft at 1,500 psi, and 0.290 cc/ft at 2,900 psi, whereas the company's PTFE braided stainless hoses expanded by only 0.0002932 cc/ft at 4,000 psi. The close-to-zero expansion to the braided hose means the brake pedal will feel firmer and will respond more quickly to brake pedal inputs, and if you've done any racing then you'll know that even a split-second faster response from the braking system can mean the difference between slowing enough to make the corner and finding yourself parked backward in the weeds.

[Rupert]

http://www.superstreetonline.com/how-to/wheels-tires/modp-0909-brake-lines-upgrade/

That's better, but it fails to test whether that difference is noticeable to the driver in any context. How much pressure gets applied to brake lines during hard braking (500 psi or 5000 psi)?

[Rupert]

Not my fault if you are unwilling to listen to the scientific reasonings why a stiffer line makes for a less squishy pedal. There's no way to "test" brake feel other than listen to people who have upgraded.

No, that is not scientific. Scientific would be an objective repeatable test, not an untested hypothesis. It sounds good to say that a stiffer line makes for a stiffer pedal, but are regular lines the limiting factor? Are stiffer lines that much stiffer? Do regular lines even flex, and do stiffer lines really flex less?

Finally, of course you can test pedal feel, it's an easy concept. Take a few different brand new cars, get a bunch of different testers. Double-blind comparative tests of the brand new OEM lines and the braided steel lines. You could also measure the strain on the lines and relate that to pedal feel.

Listening to people's subjective opinions about stuff is the worst way to learn about objective things. True experts both know their limitations and know what the objective results have been, but even then most of the time they don't know exactly the result you want.

[Rupert]

Posted in the wrong order there...

[Eye of the Tiger]

That's better, but it fails to test whether that difference is noticeable to the driver in any context. How much pressure gets applied to brake lines during hard braking (500 psi or 5000 psi)?

That's easy. All you need to know is you hard you are pressing on the brake pedal, the power assist factor, the ratio of length between the pedal and master cylinder versus the pivot, and the master cylinder bore size. So, about 1000.

[SVT_Power]

I concur. For street use just use what brake fluid the car's manufacturer says to use.  Regarding SS, I assume we are talking about replacing the flex lines.  Depending on how old the car is it might be wise to replace them.  Occasionally they deteriorate to the point that they do not allow the braked to fully release; the interior swells and acts as a one way valve.  One of the front lines on our F150 did this.  Just install good OEM quality flex lines and you're good to go.

I've cooked brake fluid before (a couple of times) on the street with the ol' SVT. It all depends on how you drive... 

[Eye of the Tiger]

I've cooked brake fluid before (a couple of times) on the street with the ol' SVT. It all depends on how you drive... 

Drive like you stole it and want to get caught, yo.

[GoCougs]

Car enthusiasts are known for their susceptibility to snake oil via their DIY don't-ask-a-professional-ask-another-DIY-guy methods. Goes both ways, of course.

Word. There are untold hours and $$$ invested in basic automotive systems - air intake to exhaust to brakes to pretty much everything else - such that there are no uncovered bones.

I think the confusion comes from the fact in believing the external covering takes the pressure. It's simply a protective covering for the layers underneath, one of which is an inner line that actually takes the pressure and that's going to be the same whether it's a SS or factory "rubber" brake line. Even if there was some expansion in the 18" of flex line it's it's gonna be very small if not insignificant compared to everything else that is going on that may affect brake feel (heating of fluid and pads, flex in the other 20+ feet of hard brake line, flex in the caliper, changes in vacuum, etc.).

[CaminoRacer]

No, that is not scientific. Scientific would be an objective repeatable test, not an untested hypothesis. It sounds good to say that a stiffer line makes for a stiffer pedal, but are regular lines the limiting factor? Are stiffer lines that much stiffer? Do regular lines even flex, and do stiffer lines really flex less?

Finally, of course you can test pedal feel, it's an easy concept. Take a few different brand new cars, get a bunch of different testers. Double-blind comparative tests of the brand new OEM lines and the braided steel lines. You could also measure the strain on the lines and relate that to pedal feel.

Listening to people's subjective opinions about stuff is the worst way to learn about objective things. True experts both know their limitations and know what the objective results have been, but even then most of the time they don't know exactly the result you want.

No one has ever done anything like that for any automotive part.

[CaminoRacer]

That's better, but it fails to test whether that difference is noticeable to the driver in any context. How much pressure gets applied to brake lines during hard braking (500 psi or 5000 psi)?

Well, multiply the expansion by 1.5 for an 18" line, then by 4 (for each wheel).

Under braking, it's usually 2000 psi. But notice the psi they used for rubber vs. SS. The SS is practically 0 at higher psi than the rubber is even tested at.

[CaminoRacer]

I've cooked brake fluid before (a couple of times) on the street with the ol' SVT. It all depends on how you drive... 

I've cooked them once, coming down a mountain side in race-car mode. Need 14.5" rotors for my heavy car.

[CaminoRacer]

Word. There are untold hours and $$$ invested in basic automotive systems - air intake to exhaust to brakes to pretty much everything else - such that there are no uncovered bones.

I think the confusion comes from the fact in believing the external covering takes the pressure. It's simply a protective covering for the layers underneath, one of which is an inner line that actually takes the pressure and that's going to be the same whether it's a SS or factory "rubber" brake line. Even if there was some expansion in the 18" of flex line it's it's gonna be very small if not insignificant compared to everything else that is going on that may affect brake feel (heating of fluid and pads, flex in the other 20+ feet of hard brake line, flex in the caliper, changes in vacuum, etc.).

There is no confusion, and GTFO of here with your "stock is best". Most new stock brake pedals are spongy garbage. Lots of assist and little feel, which is what the masses like. Performance cars change almost all aspects of the system to improve control, feel, and heat.

The inner line takes the pressure, but the outer layer can prevent the inner layer from expanding. Also, notice that many hi-po SS brake lines use a better inner line that can withstand more pressure before bursting.

SS lines aren't the holy grail of brake feel, just a piece of the puzzle.

[GoCougs]

There is no confusion, and GTFO of here with your "stock is best". Most new stock brake pedals are spongy garbage. Lots of assist and little feel, which is what the masses like. Performance cars change almost all aspects of the system to improve control, feel, and heat.

The inner line takes the pressure, but the outer layer can prevent the inner layer from expanding. Also, notice that many hi-po SS brake lines use a better inner line that can withstand more pressure before bursting.

SS lines aren't the holy grail of brake feel, just a piece of the puzzle.

Yes, you're totally confused if you truly think SS brake lines improve in any way brake feel on a 45+ year old car.

Your theory is also busted through simple logic. You're gonna have to have a fair amount of expansion in just 18" x 4 lines to affect pedal feel, and that amount of cyclical material expansion = fatigue = relatively quick failure.

Also, I can't find a car that comes from the factory with SS brake lines, including very hi-po cars:

1LE:


ZL1:


C7:

[CaminoRacer]

Didn't I already tell you to GTFO of here with your OEM BS?

Mass produced street cars aren't going to use SS for a variety of reasons, mostly revolving around cost and the scale of production. They also don't use SS hard line. OEM is NOT the king of performance, like you so foolishly believe.

Why do all major types of racing use SS?

[CaminoRacer]

Summit Racing has no idea what they're talking about. Buncha idiot noobs.

http://www.youtube.com/watch?v=hhLhj7L6CHs

[280Z Turbo]

I'm sure there is a test method for testing brake feel. You could hook up a pneumatic cylinder in line with a transducer and graph the profile of force vs deflection.

I'm an engineer. I don't believe in voodoo.

[CaminoRacer]

I'm sure there is a test method for testing brake feel. You could hook up a pneumatic cylinder in line with a transducer and graph the profile of force vs deflection.

I'm an engineer. I don't believe in voodoo.

What baseline do you set for a noticeable change? That's where subjectivity comes into play.

At worst, you won't notice a difference and you'll still have a stronger line with more protection from debris and heat. Plus, it's a new line vs. old line. I see no reason for Sporty not to upgrade. Cheap, easy, and quick, with good potential benefits (especially since he drives harder than the average joe and seems pretty sensitive to chassis systems).

[Rupert]

No one has ever done anything like that for any automotive part.

Bullshit!

[Rupert]

Summit Racing has no idea what they're talking about. Buncha idiot noobs.

http://www.youtube.com/watch?v=hhLhj7L6CHs

Buncha smart salesmen who know their audience. Notice that their number one reason is looks. 

[CaminoRacer]

Bullshit!

Prove me wrong.

[CaminoRacer]

Buncha smart salesmen who know their audience. Notice that their number one reason is looks. 

That does nothing to invalidate the brake feel claim. Try again.

Not sure why some of you guys are on a witch hunt here.

[shp4man]

LOL at this shit. Factory stuff is designed to make it through the warranty period with minimal cost and some degree of customer satisfaction. There are some designs that compromise something to achieve something else, there are other components that exceed the cost/performance ratio, others that don't.  SS brake lines are a marginal benefit cost ratio item. How much money do you have?

[Byteme]

http://www.superstreetonline.com/how-to/wheels-tires/modp-0909-brake-lines-upgrade/


Quote

When testing volumetric expansion, Goodridge found that standard OE-type rubber brake hose expanded by 0.136 cc/ft at 1,000 psi, 0.150 cc/ft at 1,500 psi, and 0.290 cc/ft at 2,900 psi, whereas the company's PTFE braided stainless hoses expanded by only 0.0002932 cc/ft at 4,000 psi. The close-to-zero expansion to the braided hose means the brake pedal will feel firmer and will respond more quickly to brake pedal inputs, and if you've done any racing then you'll know that even a split-second faster response from the braking system can mean the difference between slowing enough to make the corner and finding yourself parked backward in the weeds.

Let's see, assuming those numbers are correct  0.1346 cc is about 2.5 drops of fluid, not a large amount by any accounting.  How many CCs of brake fluid are displaced when one steps on the brakes? 

I love that statement concerning quicker response to brake pedal inputs.  If true, how much more quickly will the brakes be applied with SS brake lines; t1/100 or 2/100 of a second at the most?  I assume it matters most when you have a situation when you really need to stand on the brakes.  Those times translate into 1 or 2 feet of travel at 70 MPH.  Better tires would have a much larger impact.

A problem that has manifested itself with the braided SS brake lines hasn't yet been mentioned here.  There have been numerous cases of very small grit working through the braid and abrading the Teflon inner line.  Added to that is the problem of the braid covered line continues to look sound while it may be deteriorating while conventional flexible brake line shows outward signs of deterioration.


Some other thoughts:

1.  The people touting the virtues are mainly the people selling the product.   On most car forums I've looked at the jury is still out.

2.  Porsche, to the best of my knowledge use rubber flex lines on their racing applications.  You'd have to ask them why, but I suspect the reason has nothing to do with cost.