I am going to replace the old brake hoses on my e30. After doing some looking around on the interwebs it seems that everyone has an opinion and none of them are the same.
Car will be daily driver plus some autox.
You guys always seem to have a lot of knowledge on stuff like this and a (mostly) grounded viewpoint. What say the hive?
Is cost an issue? Unless they're assembled improperly, stainless doesn't really have a downside other than being more expensive- I only run them on motorcycles and racecars, and use rubber on everything else because I'm cheap.
The only real downside is that they can eat other things if allowed to rub. Installed properly, I wouldn't hesitate. Heck, I have them on most of my vehicles.
I have heard that they make the brakes stiffer at the pedal. True?
I really don't want a stiffer pedal. I had to swap in a smaller booster to clear my intake so it is pretty stiff already
If the rubber lines are flexing a bit, the stainless lines will make the pedal firmer, but they won't increase pedal effort like the smaller booster did. You'll still push the same for a given amount of braking, the pedal just might not move as far when you're really leaning on it.
So if I am understanding correctly. They would take out some of the 'take up' on the pedal but would not increase the overall effort required to stop the car?
In reply to Daeldalus :
Correct, makes it easier to modulate when threshold braking too.
Theoretically, the pedal effort would be less, as more of your leg push would be translated to pads against the rotors instead of expanding out the rubber hose first, then pads against the rotors. Now if that is measurable or not is another question. People do say that the stainless lines, which are not stainless, but probably PTFE, make the pedal feel firmer.
Are the cheaper ones even worth the time to look at?
Should I just skip straight to the 180$ set that is DOT approved?
The good sets with a nice outer coating, etc. will almost definitely last longer. The cheap ones are more susceptible to dirt getting into the stainless and wearing out the inner liners.
NEALSMO
UberDork
9/29/17 11:19 a.m.
The way I see it is that if they make your pedal stiffer, than your old lines were failing. What they are really for is avoiding swelling under high temps like rubber hoses sometimes do.
I am not worried about high temps. Autox shouldn't heat the fluid too much and neither should daily driving.
But that said, if I did stainless that wouldn't matter anyway.
In my case, I installed them on my celica. I have factory rotors and calipers, only aftermarket EBC pads. Installed Ss lines (cheap ones from techna fit) what changed was the feel of the end of the brake pedal stroke. Instead of it being “spongey” when the pedal catches, it’s seriously THERE. There is no “mushy spot” where you can’t tell how close you are to locking them up. It alters the pedal at the END of the stroke. That’s where the expansion of rubber line occur, and that’s where SS line make the difference. The rubber lines don’t expand first, the rubber line expands LAST, after the hydraulic fluid has reached its expansion limits.
I don't use the SS ones so I don't know, but I saw a lecture by Mike Sneed once. He recommended stainless for racers and other owners that were willing to replace them every few years, and stock polymer lines for the HPDE crowd or the budget-minded. He said something about the tubing inside the SS jacket having a tendency to collapse or something without showing any external indications which line was the bad one, but with a polymer line he could always spot which one needed replacing.
Also, it's not a hard job to do a complete inspection of all the hard lines on an E30 brake system. I would go over the whole thing tapping it firmly everywhere to make sure there are no weak spots. Twice now when I've replaced one polymer line on a 20-year-old car it turns out that line was acting like a little expansion tank. Once it was gone, a weak spot in the hard line elsewhere in the system burst. While my son was driving the car.
Go for the full DOT stainless ones if you want to do it. Another downside nobody's mentioned yet is that because stainless lines aren't as flexible, they need to be longer to be able to bend at the same angles, which can create a packaging problem.
I have them on my Corolla. The difference is only really noticeable under sustained heavy braking (like braking at the end of a track straight), and it's not huge. For a DD & autocross car, I don't think they're worth it.
I would only consider them for track cars. For the OP standard lines are fine.
NEALSMO said:
The way I see it is that if they make your pedal stiffer, than your old lines were failing.
Exactly - there shouldn't be much difference in pedal feel between a good rubber hose and a stainless one.But there will be between an old rubber hose and a stainless one. I've seen a clutch line swell so badly you couldn't move enough fluid to disengage the clutch. You can think of a failing line as adding a spring rate to your pedal.
I like the armoring they provide. I've had rocks take chunks out of the sheath over a stainless braid, I'd hate to think of what that would have done to rubber.
I'm sure I'm gonna get flamed but I don't think SS lines offer any better performance over new factory lines. The SS essentially only protects the inner line from chaffing/damage.
In 15 years of club racing I saw more incidents of brake line failure at the fitting in SS than with OEM factory. Not many with either but more in SS. If you do go SS make sure they're DOT approved/tested.
You could use SVreX' s trick of adding zip ties to rubber lines and get just as much performance gain. SS=pure placebo effect.
YMMV. But they look purdy.
Ovid_and_Flem said:
I'm sure I'm gonna get flamed but I don't think SS lines offer any better performance over new factory lines. The SS essentially only protects the inner line from chaffing/damage.
In 15 years of club racing I saw more incidents of brake line failure at the fitting in SS than with OEM factory. Not many with either but more in SS. If you do go SS make sure they're DOT approved/tested.
You could use SVreX' s trick of adding zip ties to rubber lines and get just as much performance gain. SS=pure placebo effect.
YMMV. But they look purdy.
You won't get any performance improvement but you will get a slightly more solid pedal feel under heavy braking. I had zip-tied factory lines before the SS lines, it was still a slight improvement going to SS, similar to the improvement from adding the zip ties.
In reply to GameboyRMH :
I would be willing to bet you 99.9% of drivers could not tell the difference between new OEM lines and SS lines in a blind back to back comparison test.
Racing drivers or all drivers? Because I'm pretty sure 99.9% of drivers aren't racing drivers and indeed wouldn't notice the difference
Among racing drivers, I bet that in a blind back-to-back comparison, including threshold braking without ABS at the end of a long straight, 3/4 could tell the difference.
In reply to GameboyRMH :
Placebo
Surely somebody in here is a hydraulic/fluid dynamics engineer and can settle this academically
I'm with Ovid and Flem.
If you go from worn out and busted rubber lines to good stainless lines, then sure, you will notice a difference (as already noted in the thread).
From my perspective, if OEM lines start to noticeably expand under the pressure or heat of the stock brakes, then the OEM engineers really failed at specing lines. (not saying that can't happen, just that it should not).
Even OEM rubber lines have metal in them, no?
Edit: looks like cord. Considering how strong cord can be in tension, (and materials that are NOT affected by heat like, ahem, metal, can be selected), I stand by my assertation above.
In reply to Robbie :
I'm sure the cord's plenty strong, but how rigid is the total structure? I suspect that cord in matrix has to be expanded slightly before it's actually in tension (?), and the compressibility of the inner liner layer (rubber, polymer, teflon) also has to be taken into account. I'd think. Not in the hydraulics business, so just semi-educated-guessing...
I have way too few data points to feel like I have The Answer, but my limited experience and that info combine to leave me currently under the impression that the braided lines do provide a firmer pedal with less motion over a given range of pressure. For all I know, that's at least as much to do with the Teflon than the SS, but package vs package, that's what I've got.
Now I really want to back to back some brand new OEM lines and SS lines...
I put DOT approved ss lines on my disco. I did it for the protection from rocks and such and because I tow and do not need line expansion at the limit (which you reach a lot faster with a trailer behind you) Compared to the old, probably original lines, it was night and day, I enjoy the more firm pedal and the lack of "give"