r911

I use rubber brake hoses from the dealer (which should be TUV approved; and that approval means a lot - much more than a DOT approval).

I changed to rubber when I bought my '73 (the PO had the stainless steel covered hoses on there) and I detected no difference in pedal feel.

In addition, rubber hoses allow you to squeeze them every year and check for problems, while the braid covered ones do not allow those safety checks.

Here is what some real experts have said:

Sept. 1986 Pano.; Up-Fixin’ VII, p. 161
BA reported soft pedal feel with hoses larger than -3
- some thin wall Teflon was sold and this caused ballooning of the hose giving a soft pedal feel and risking bursting and brake failure
- stretching or crimping of the hose (e.g. by having hose the wrong size or in the wrong location for the wheel movement) could cause sudden brake failure


Excellence, Oct. 1994, p. 48-52
- steel brake hoses become stiff over time and may spontaneously loosen from the caliper or metal line
- “quite a few have failed over the years” while only a single rubber hose was known to fail – Bruce Anderson

Steel hoses are fine for a pro race car, where the car is completely disassembled between races

Feel & Performance on Real World Roads:
the rubber OEM brake hose give a better feel than the Teflon/stainless
steel braid type hoses on imperfect road surfaces, or when the tires
and rotors are not perfect – even almost undetectable imperfections
can have an effect at the limit of braking.
- slightly paraphrased from Grady Clay

There is also some info in the Dec. 1983 Pano,

and there is this:

theiceman

so was there a question or did I just miss it ? did I step in here half way through a thread or something ?

r911

came up on another thread, so I thought I'd create something that can be pointed or linked to

tgil

Good information.

Was just considering and discussing stainless brake hoses recently and this information seems to confirm the use of rubber for street use or unless owner is confident inspecting or pro mechanic can periodically inspect.

r911

I forget who said that "inspection" is really replacement after each race or every year for the SS covered hoses. But it was someone whose opinion I respect.


The SS mesh prevents you from inspecting the hose inside - with rubber hoses, you just get down there and squeeze them.

73911

I put braided brake hoses in the same category as drilled brake rotors.

Bling Bling Bling

Richard Newton
Historic Racing Images

theiceman

lol I see .. rubber all the way ..

grgallo

^ 73911, my '87 911 came with Zimmerman drilled rotors (previous owner from West Hollywood) should I replace them, my car is street only, thanks

CAporsche

Regular inspection and maintenance is critical. In my previous street/occasional track cars, I have used SS lines and I have felt a difference in pedal feel that I like. I'm new to the 911, so I'm curious to see if I notice anything different on this car; if not, I have no problem going back to stock lines.

r911

The are likely cast holes; maybe drilled to finish.

I'd inspect for cracks near the holes frequently. When replacing, I'd use slotted rotors.

73911

One of the problems with installing aftermarket parts is that we use them to replace worn out factory parts.

There is no question that braided stainless brake lines are superior to 30-year old rubber lines. A lot of times you can even feel the difference.

Now when you compare brand new OEM lines to the aftermarket lines braided steel lines there will be no difference. And, the OEM lines have had to go through the TUV approval process..

Richard Newton
Historic Racing Images

09mageec

For the stock, rubber brake hoses in discussion, what is the part number? I want to do a check this afternoon and see what the car has. (It's new to me)

porsche0nut

We all know that using rubber affects how it feels



Joking aside - you make a good point r911 about the inspection. Very difficult to inspect the stainless lines except to apply pressure and look visually for leaks. However I'd think you'd also find your pedal feel would go soft and you would go through brake fluid pretty quickly if they were failing.

I'm also guessing there have been some reliability and quality improvements in the 30 years since the sources from OP. Maybe stainless lines from the 80's weren't deemed a good upgrade - what about from 2016?

porsche0nut

Agreed - regular inspection and maintenance is far more important than the style you decide to go with.

cairo94507

I spoke with Eric Shea at PMB Performance when deciding what to do for my brake restoration/rebuild. He is, as far as I am concerned, the brake guru for Porsche and other European cars. He too recommended staying away from the SS flex brake lines, he knows my car will only be street driven, and said that the factory rubber lines are the way to go for all of the reasons mentioned above. I took his advise and that is what I bought. I also replaced all of the brake lines throughout the car, the master cylinder, proportioning valve got rebuilt, calipers rebuilt, rotors replaced, etc. Given that in '71 brakes were your main safety system, I didn't want to mess around and take any chances.