997 Brakes lines- Kunifer or Steel

911virginowner · Sunday at 7:36 AM

Hi all
I need to change the front and rear brake lines on my 997 due to corrosion. This is a big job since I think the subframe and gearbox need to be removed.
My concern with using steel is that it will rust again over time and I want to future proof, not just for me but also for any future owners.
Anyone changed these before using kunifer and if so, is this a good idea and where could I buy a ready made set of kunifer pipes from?
Any advice appreciated.
Many thanks, Raj

ianthow · Tuesday at 8:21 AM

You won't find ready made kunifer pipes.
With the correct kit for bending pipes and flaring the ends, they can be fabricated easily. The important thing is to avoid sharp bends or kinks that cause stress points. I used to be against copper pipes but these are used extensively by many garages (including some OPCs if you ask, but may invalidate an extended warranty). They are acceptable for MOT purposes, so I guess they are reliable for normal road use (maybe less so if the car is to be tracked).
Earlier this year, I had EVERY underbody pipe on my 987 replaced by a local garage. The stipulation was to retain the original pipe runs and clips, with no inline connections. There was just enough room above the steering rack and above the gearbox to feed the pipe through and clip in place before completing the bending on the second side, all without dropping the gearbox or crossmember). The plastic clips become brittle with age, so quite a few new clips were required.
They billed me for 14 hours work plus material. I bought the required clips from the local OPC with Porsche Classic discount.

911virginowner · 2025-08-27T05:30:14+0100

That's very helpful coming from someone who's been through this, thank you.
I'm going to have a look at all pipes alongside my porsche specialist and take it from there. So glad we get 10% off parts at the main dealers!

ianthow · 2025-08-27T08:15:29+0100

911virginowner said:
That's very helpful coming from someone who's been through this, thank you.
I'm going to have a look at all pipes alongside my porsche specialist and take it from there. So glad we get 10% off parts at the main dealers!

My main motivation for copper was that I had been cleaning, treating and painting pipes every two years to preserve them for as long as possible (the car is used in all weathers, all year round). At 15 years old, I decided new pipes were in order, including flex hoses. I originally asked the OPC to quote. The pipes and hoses alone were over £1000 plus 16 hours labour at OPC rates. The trouble is that some of the new steel pipes in exposed areas will begin to corrode after four or five years and then it is downhill all the way. Copper will last a lot longer and was going to be more cost effective, hence the decision. Replacing EVERY pipe was not essential at that time, but I just wanted to put corroded pipes behind me (the car is a keeper). I also bought a set of Goodridge braided hoses from Design 911 (for half the discounted cost of OE factory hoses from Porsche) to be fitted at the same time. The old ones looked fine, but at 15 years old, replacement along with the new pipework seemed prudent.
Also on brakes, I replaced all the original steel bleed nipples with stainless ones about eight years ago after one snapped and two others tore out the threads in the alloy calipers during a brake fluid change. Worth considering if not already done on your 997.
On the subject of calipers, about three years ago I found fluid leaking from the bottom of a rear caliper due to a pinhole in one of the pipes linking the caliper halves. The pipe looked fine, but I needed the car urgently so removed the offending pipe and took it to the nearest garage where they made up a copper replacement (re-using the rubber protection sleeve on the pipe.). I suspect the leak was from hidden corrosion under this sleeve. This emergency repair was my first foray into copper pipes. The other three caliper link pipes were replace this year along with the underbody pipes.

911virginowner · 2025-08-27T12:42:32+0100

You have been very thorough and I may have to go down a similar route. Thanks for sharing your experience and knowledge.

paulus · 2025-08-27T23:57:31+0100

I've not changed the pipes on my 911, but have on numerous other cars.
Never use steel, nothing you can buy will be even as "good" as the OEM plastic coated pipes. Steel is hard to bend & will rust fast.
Kunifer - a copper & nickel mix is the only material worth using as it is relatively easy to bend & will not corrode, is strong enough to resistant damage due to stone impacts etc & will not fatigue easily.
Kunifer usually lends itself well to "threaded" through small gaps where the OE pipe was installed originally. It's relatively easy to create good quality pipe "flares" in situ on the car, meaning the nuts don't get in the way while threading the pipe around the various "challenge" areas. The flares usually seal well - whereas with steel pipe it's much harder to create good flares without expensive professional garage quality flaring tools.

BEWARE not to buy pure copper pipes. It is very easy to bend, very easy to damage & fatigue / fail fast if subjected to vibration / frequent movement. I think in the US they've even banned the use of copper for aftermarket pipes - although that maybe an urban myth.