postalpete

I'm wondering if there is a performance reason for going with Stainless steel hoses instead of the standard rubber on a street driven mid-year.
I have added power brake correct dual master cylinder so I could have separate front and rear brakes but wanted to know if stainless gives a firmer pedal or it's just marketing?

JohnZ

Road-racers who are on the brakes HARD every time and have a feel for modulating brake apply effort prefer the stainless lines for a firmer feel under max braking; for a street-driven car, you'd never notice any difference.

tuxnharley

..........is safety and reliability!

John is the recognized expert here, and I don't mean to disagree with him as to pedal feel between the two types, but I believe there is another huge advantage to using the stainless flex lines - they don't deteriorate from exposure to grease or oil.

I have the stainless flex lines on my '67 for 12 years now, and they are as good as new. I think they are a teflon(?) tube liner with the braided stainless outer flex covering. They have a higher burst strength than the rubber lines, and are impervious to deterioration from grease and oil contact. Rubber lines will get hard and brittle over time, and I have had them burst on other cars................not fun!

I went with stainless sleeved calipers, silicon fluid, and the stainless flex lines. The brake system is like new 12 years down the road. Some say silicon fluid can get "aeriated" under hard use, but I have never had that problem.

I recommend the stainless flex lines along with the other things I did for a driver. On the other hand, if it's going to be a show car and you're worried about judging and satisfying NCRS standards, you'd better use the rubber lines - if you can find date coded ones

Best wishes!

boxster99t

Not sure what the recommended change intervals are, but even braided stainless steel flex lines wear from the inside due to the long term effects of brake fluid. 12 year old lines surely wouldn't be good as new, but they may still be serviceable

Make sure to replace them at whatever the appropriate interval is (and I am not an expert, so I don't know what that may be--12 years might be long in the tooth).

Also, the other claim I have read on brake hose with stainless steel braided jackets is protection from impact damage (for off road vehicles--not a consideration on a Corvette, one hopes).

tuxnharley

.........my understanding is that the combination of the teflon liner and the silicon fluid - why is non hydroscopic (doesn't absorb moisture) and therefore doesn't deteriorate - means that there is no interior deterioration like there is with conventional fluid and rubber lines.

I have heard that many museums use silicon fluid so as to preserve their cars.

If I'm wrong I'd be willing to learn!

Thanks!

BADBIRDCAGE

I don't know but it could be true.

I am not now, and never have been, a fan of silicone brake fluid so I don't use it in my vehicles. Just my preference.

KC John

My understanding for the use of silicone brake fluid is that it doesn't absorb moisture the way Dot 3 does, so you don't get rust forming.

Kensmith

I switched to the braided stainless because my car would pull when braking. Also, much safer than rubber that may crack, bulge, stretch, etc. Made my power brakes much better and pedal much firmer.

boxster99t

It's not a rust issue regardless--the brake lines being discussed are the rubber vs. stainless steel braided flexible brake lines that come off the main metal brake lines, allowing the suspension to move up and down. Whether it's rubber brake lines or the telflon sleeve inside braided flex brake lines, neither will rust from DOT 3/4.

I know many manufacturers warranty the stainless steel braided brake lines for the life of the vehicle. That doesn't equate to forever, more like the average life of a vehicle whatever that is or possibly until you need to remove them (for example, lifetime coolant is good until you have a coolant system issue or water pump replacement). So I'm just wondering how much time is in a lifetime warranty?

Not sure what the upper limit is nor how impervious the linings really are to either DOT 3/4 or DOT 5 brake fluid. I know that PVC tubing that is chemically resistent and intended for brake fluid applications doesn't last forever and some of it is very expensive. Tygon for example is some high dollar brake line tubing.

I suppose regardless of which you use, with the rubber you know to replace it every 8 years. With stainless, when? I suspect longer, but never? I don't know.

JohnZ

ALL rubber brake flex hoses made since 1970 are dated; if you have some that aren't, it's long past time to replace them.

Mike Ward

NCRS does not judge date codes on brake hoses, current service replacements get zero deduction.

JLMICCA

Concerning brake fluid and being hydroscopic or not. My understanding is that the hydroscopic nature of DOT 3 and 4 fluid is an advantage in that any moisture that is absorbed would be distributed throughout the system thereby eliminating pockets of water that could cause brake line corrosion or areas of relatively low boiling point. This does, however, that hydroscopic fluid is regularly flushed from the system to eliminate absorbed water. Silicone fluid is non-hydroscopic which means that if any moisture is absorbed, it collects in focus areas which can cause internal brake line corrosion. Also, as previously stated, silicone brake fluid should never be shaken as it tends to aerate easily.

66since71

There are literally 30 to 40 million cars made world wide each year with rubber hoses. When was the last time you heard about a failure?

Unless you are racing, and need that fine margin of pedal feel, my vote is rubber. (Remember race cars get their brakes serviced at least once each race weekend...)

Harry

Kensmith

Harry,

My son had a Chevy S-10 with only 60,000 miles and 6 years old. The r-front brake hose under normal braking burst. Almost caused an accident. I was also very surprised as it looked to be in good condition. You never know.

66since71

You are right Ken, you never know. Glad you son made it OK.

My point was that the product technology is mature and well tested and that the manufacturing technology is very repeatable.

My guess is that the stainless hoses don't meet any of these criteria in this application. They are likely made in specialty shops with limited R&D and testing resources and very little automated equipment (so we rely on someone doing it manually to do it the same way every time)...

Harry

yukonranger

Aircraft manufacturers recomment replacement of rubber (or rubber lined stainless braid covered) hose every five years but there is no recomendation to ever change teflon lined hose unless there is damage. It doesn't matter what fluid is inside.

toddalin

Recognize that many of the stainless lines are not (or at least were not) DOT-certified and therefore illegal to use on public roads, though most are now. Be sure to get a set that are DOT-certified.

sub006

One benefit of silicone fluid is it doesn't hurt your paint if you accidentally drip or spill some on a fender.

62fever

One issue I have experienced with rubber hoses that I think would be solved with the teflon/ss hoses is an internal swelling. In my case, I think the rubber hose had allowed brake fluid to permeate and the i.d. of the hose closed up enough to restrict fluid flow. This caused the fluid to keep a clamping force on the disc. Outside looked fine but would keep the brakes partially applied going down the road. Noticed the problem when vehicle would pull to right or left after stopping.
Even if the teflon had some type of permeation, I don't think it would cause it to swell and restrict fliud flow.

Bill32

Yep, that's pretty much it. Different environment with racecars.

You won't notice a difference on a street car, any difference you notice will come from replacing worn out fluid and (possibly) a very old rubber hose.

Rubber hoses will be fine and last many years. If SS gives you some peace of mind, by all means, put them on. Yes, check for DOT cert. but most sold today are.

Hose failures are very rare, rubber or SS. If your rubber hoses have cracks, it's time to change them. SS lines do last longer but that's not enough reason by itself to change to them.

In addition to pedal feel, we use SS lines on the racecars for abrasion resistance (just in case something's rubbing) and (more important) to reduce the possibility of a piece of debris from another car hitting the lines at high speed and cutting it.

Change interval for SS lines? There's nothing specific, there's 1000s of vintage racecars running old SS lines with no problem, my vintage car has SS lines that are 25 years old and I'm not concerned. I've never seen a line just break and I do tech on these cars.
Can it happen? Sure, but it's extremely rare, rubber or SS.

A note on silicon fluid, it's advantages for not absorbing moisture and not hurting paint are correct. BUT, silicon fluid is not compatible with DOT 3,4 glycol brake fluid. Just changing to silicon by bleeding the system is not good because some glycol fluid will still be in the system.
If you go to silicon, everything should be new or disassembled, cleaned, etc.

We don't use silicon fluid in the racecars because it has a tendency to retain a little bit of air and definitely has a different pedal feel because it's slightly compressible.
For the street, it's a non issue.

The thing that most people don't do is change their fluid. I do my street stuff every 2 years.