911/ 930 fuel line replacement, tank back

chuffysplace · chuffysplace's Garage

I need to replace the fuel lines on my '86 930. The supply and return lines that run from the tank towards the back of the car. Can anyone offer help or advice on the best way to do replace those? Would it make sense to use the stock type lines or just go with aftermarket AN type (the car has those already on the engine side from the previous owner). Also, I wasn't sure if the supply and return lines are long piece rubber lines that run under the tunnel or if there are steel lines in the tunnel with rubber lines on the tank and engine end. Thanks.

chuffysplace · chuffysplace's Garage

It looks as if the tunnel lines are separate, made of steel but coated in plastic. If anyone has any additional information, or can verify this is correct, or provide info the above, please let me know. thanks in advance.

kojo911 · 03-19-2015, 05:09 PM

I did this on my '73 911. Major PITA. When I did it a couple years ago, the parts where no longer available. I used -6 aluminum fuel lines with AN fittings. The car is a hot rod so factory correct was/is not necessary. TurboKraft has done a few of these, Chris frequents these pages. I think they use -6 flex lines w/ AN fittings. If you have the tools and patients it's tough but doable. If you search the 911 tech pages there have been a few pelican's that have done it, either using factory lines, braided (flex) lines w/ AN fittings, or aluminum fuel lines with AN fittings (available from any speed shop).

Jeff NJ · 03-19-2015, 05:19 PM

I just got replacement lines from BoxsterGT. (Len). If you search, you will find his work is very highly rated. I sent him my old lines so he could exactly match them, so he now has exactly what you need.

I am not a big fan of braided steel for standard applications, because it will rub all sorts of things and possibly damage them, since the original routing does not take cable clearance into account. Besides, it is just the same rubber underneath...

dap930 · dap930's Garage

The tunnel lines are made from polymide. The factory tunnel lines change over to rubber hoses at the front with barbed fittings. At the rear the tunnel lines have 14MM connections where the hoses attach to lead to the rear fuel pump and return. I have replaced all my fuel lines on my 930 with new tunnel lines and hoses made by Len Cummings. His replacement tunnel lines have 14MM connections at each end so the front hoses can be changed individually. Since these new tunnel lines have a 14mm connection at each end, the front of the new line can be connected to the rear of the old line, which allows the new line to be pulled in as the old tunnel line is pulled from the front. Also, if you want to change your rubber hoses for custom install, Len can make them too. Also, these rubber hoses are compatible with enthanol. Do a search on "tunnel line replacement" and Len Cummings, and you will get lots of information, as many have already gone through this process.

Walt Fricke · 03-19-2015, 06:42 PM

There isn't all that much room in the compartment in the upper left side of the tunnel through which the fuel lines run for most of their length. The compartment keeps them out of the way of other things in the tunnel. Which is one reason to stick with the factory type lines and their routing.

chuffysplace · chuffysplace's Garage

Thanks all. Appreciate everyone's info. I should be good to go.