Fuel Lines Leaking on my '81 SC... HELP!

shillier · 07-04-2006, 05:51 PM

Hi,

Hope someone here can help me out. I'm usually able to fix most of my issues with the car but starting to feel somewhat overwhelmed with the situation and wondering if I bit more then I can chew.

Last year, one of the hard fuel lines from the tank to the engine bay sprung a leak. I brought it in to the local porsche shop and they "fixed" it apparently. Now that I look at it, they patched it up with a small piece of flex hose.

A couple days ago, the second hard line (I think) sprung a leak as well. Gas all over the place just under the tranny.

I'd really like to change these but I'm not really sure where to start. The engine and trans are partially lowered already. I'm not sure though what type of lines I need.

Replacing these hard lines looks like quite the job. Do I need to replace them with hard lines or will the nylon lines do.

I've read all of the threads by Jim Sims but I'm still not sure what type of lines and sizes I should be going with? I've only seen what's in the engine bay... what can I expect at the other end near the pump and tank? How difficult are these hard lines to remove and replace?

Any help is greatly appreciated! BTW... the car is an '81 SC.

Thanks!
Shayne

walt · walt's Garage

Are you talking about the hard line from the tunnel to the engine bay? If so, you will want to use only steel to replace it. Nylon might abrade on the firewall sheet metal due to the engine vibration. I purcahsed a coil of 5/16 OD steel fuel line you will also need a good flaring tool and a bender. It was a bit difficult to make some of the bends required due to the hardness of the material.

shillier · 07-07-2006, 10:10 AM

Hey again!

Can someone tell me what size the OD of these fuel lines are? are they 8mm or 5/16?

Thanks!
Shayne

bkreigsr · 07-07-2006, 11:30 AM

you might be able to get away with just replacing the supply & return lines from the rear bulkhead to the pump. my flex portion of the supply line split open after the fitting on the outside of the rear bulkhead. I had to disconnect the starter and have my wife turn the ignition on to get the pumps working, then was able to see where the split was. lucky for me it happened just as I was pulling in my driveway after a trip to the track, otherwise the car probably would have gone up in flames. I was able to temp patch it by cutting away the split and putting in a hard line and some hose clamps. (that still weeped). getting access to the fittings to get a wrench on them is half the fun. had to disconnect clutch cable, maybe speedo as well.

also, Porsche has no lines with non-metric sizes. 8mm sound right

shillier · 07-07-2006, 01:11 PM

Thanks for the info...

I'm thinking as a temporary fix, to simply fix the line with a high pressure coupling. I found some on mcmaster.com that are for this exact purpose on page 145 of their catalogue.

I was hoping to get through the summer with this and change the lines in the winter when the car is off the road.

thanks.

shillier · 10:39 AM

Ok... after taking closer look... the line is finished and only runs from the engine compartment to the tunnel then connects to some rubber lines. So I've decided to simply change these two steel lines.

I figured I'd just make my own from 5/16 steel lines as per Walt's reply above... so I've got a couple questions. Do I use a 37 or 45 degree flare? Anyone know what size the fittings on the end of the steel lines are? I assume I'm going to have to replace those since I'm going to change to a 5/16 line.

Thanks for the help.
Shayne

David · David's Garage

To be really safe, I'd buy new fuel lines and replace them. They can be replaced in about 2 hours. Of course they're a bit expensive. Another option would be to use braided hose but you'd probably spend as much as OEM lines.

Porshce fittings are spherical not flare.