Fostering Classi

So now the car is running, it went for it's first MOT (annual safety check) and failed on the following

Right rear service brake not working. Ive cleaned the pistons and ensured pads are free, but it seems like fluid is not being supplied even though the left hand one is fine.

Steering rubber components to replace

Fuel lines badly corroded. I need to change the hard fuel lines. Has anyone done this? Any tips? It looks like the pipes are installed prior to suspension and powertrain in the factory, so their routing is complex. Has anyone used cupronickel pipe and made their own, rather than buying Porsche ones?

GerritD

I had the same problem 8 years ago. Since these fuel lines are NLA, I replaced my fuel lines by braided PTFE lines, also used in race cars.
Flexible, temperature and rust resistant.
The only thing that needs to be done is clamp the original connectors onto these ptfe lines via professionally pressed clamps.

martin D

I just done it on an S4, yours is an S2 I guess with the extra line in the wheel arch?
If you take the panel off at the front of the RH rear wheel arch there is a joint in the fuel line, easy to replace just the wheelarch line. Yes I replaced just that piece with one I made using the copper nickel stuff

martin D

Gerrit, as was mentioned on another post, you cannot safely crimp Teflon hose to the smooth cut off ends of fuel line in your photo, it is foolish to recommend to do it as it is very unsafe to do so, your last photo is a proper hose & fitting, made for each other, not hose and smooth pipe.

just_drive

Great to see a discussion of the hard fuel lines....I was just digging into this topic and found tons of info on the rubber fuel hoses, the correct fixes and connections but really nothing on hard line replacement or even inspection/replacement procedures. So, other than external corrosion what are signs of trouble an owner should be looking for with these lines? Are there known trouble spots?

And since these are NLA does anyone have a preferred web link or brand name for everyday usage replacement lines AND associated connection pieces (if also NLA). I see the 928 body connectors are still available from several vendors so I would want new lines that can use these when needed. I am in the process of inspecting my fuel system after a dead pump, and it looks like my rubber fuel components have been replaced by the PO (correctly it appears!), so what is the life expectancy of these hard fuel lines? With no outward issues, does the 928 fuel system need regular flushing or some maintenance? Thanks.

Mark
'89 S4 Auto, USA

martin D

They are still available, I got all 4 of the under the floor fuel lines from Porsche only last week, not that I would recommend getting them as they turned out to fit very badly and were a pain in the *** to fit, it would have easer to have made them myself out of copper-nickel tube

karl ruiter

I have had the same problem. I was looking at https://classictube.com/ and wondering if they had the fittings and could do the flares. I'm not really sure what the specs are on the stock fittings, so I'm not sure. On my '79 I used this stuff: https://www.summitracing.com/parts/r...SABEgKdlvD_BwE. The fabrication was easy...you pull off the fittings off the stock rubber lines, heat the new line with a heat gun, and slip the fitting in. And in theory is is...ok? Because this stuff is what really does the work inside the stock rubber lines. And because it really is designed to be fuel line. I replaced the hard line, the rear soft line, and the front soft line with a single length of this. In practice, though, I am scared to drive the car much this way.

dr bob

If you can get the old lines out without distorting them, my vote would be to form up new piping with a proper tubing bender, install new ends and do the proper bubble-flares on the new piping. Resist the temptation to "just" bend tubing over your thumbs; it's really easier with the right tool. Make marks on the tubing for center of bend and the bend axis, easy while you have the old line out to use as a model. The tubing itself is inexpensive, the fittings are not at all exotic, and with a little practice on some scrap you'll be doing the flares easily. Hints: use tape to restrict the end fittings to the ends while you bend. No need to ask how I know. There may be a good case for some powder-painting on the tubing after the line is completed. Be sure to use good fuel-proof thread sealing paste or anti-seize where the flare nuts fit onto the tube, and again on the threads of the flare nuts. You'll be blessed with connections that can be easily disassembled in the future that way. Thoroughly check for leaks before you drive. Probably OK to use shrink tubing on wheel-well sections as added protection from debris and abrasion. Buy extra tubing up front, so you don't have to cry and drive when something goes left instead of right. Practice the flares on scrap sections before committing a whole beautiful formed section. I've done hundreds of these over the decades, and I still do practice flares first to get the feel of this particular tubing.

martin D

ISO/DIN is the correct spec, this is not just 'metric' as you can get metric SAE fittings which look similar, but are wrong,
There is an SAE bubble flare & an ISO/DIN bubble flare, they are not the same.

Broccoli

I tried the method of pulling my old lines off an having a fabricator (a hot rod shop) duplicate. It didn't work. I haven't done all the troubleshooting, but I suspect it's not ISO/DIN. Also the line was kinked in a few places.

So I'm looking into using the braided steel. Assuming I can have someone fabricate for me or I can buy/borrow the crimping tools (as I don't have crimping tools), how do you think these will route under the car and around all the twists and turns. If I cut the rubber out of the existing braces due to the larger outer diameter - will the stainless line behave under there?

Else I could do a compression fitting on a clean part of the original fuel line and adapt that to a shorter flexible.

Else I could fabricate an entirely new line...

GregBBRD

Make your own.
Fedhill Trading Co. Is where you need to go.

grepin

I have no idea if these have been done correctly or not. But this guys videos are a great example of DIY.