Fuel Line Leak Help: '81 SC

[mzavada]

Hi everyone-

Could use a bit of help determining the correct repair on a fuel line.

Background: I've had the '81 SC since 2014, never had an issue with the below. Early spring 2017, pre-snow thaw, I changed out the fuel filter as part of regular maintenance. First drive of the year, smelled raw fuel, determined that it was the line from the distributor to WUR. I had assumed that while I was changing the filter, I bumped this line and since it was older/starting to become brittle, that is what caused it to start leaking fuel.

Repair 1: At the time of the leak discovery, I found the exact spec hose as what I took off the car, at my local parts store. I replaced the hose and clamps on both ends. (Different style clamps than what I took off) I've driven a couple hundred miles without any issues until...

Current status: Fuel sprays out under full pressure (not really a 'leak' like before), and at enough volume to cause fire concerns.

Theories:
1. Hose has wrong I.D. spec (doesnt explain how I had years of trouble free with the same spec hose)
2. Utilizing wrong clamps to hold hose (might be a combo of 1 & 2)

Actions: I plan on at minimum swapping back on the original clamps, to eliminate that as a variable.

Question: What else should I be doing? I have a few longer road trips planned this summer, and this is causing enough of a fire concern that I'm VERY hesitant to not figure out a permanent fix. Thoughts? Suggestions?

[Dr J]

That looks like a home-made repair. The original fuel line did not have hose clamps. I would put a WTB ad in the for sale forum.

[mzavada]

Originally Posted by Dr J

That looks like a home-made repair. The original fuel line did not have hose clamps. I would put a WTB ad in the for sale forum.

In searching for parts from our host, it looked like it might have been a hard line, and threaded...is that what your thinking is?

[Dr J]

It's partly a hard line and partly a fuel rubber hose. At the fuel distributor head it come out as a steel line. It is crimped to a rubber line which is connected via a tight interference fit (without hose clamps) to the connector that then attaches to the WUR.

[Flojo]

Originally Posted by mzavada

..it looked like it might have been a hard line, and threaded...

what you show is the line to the WUR (warm up regulator)

1981 onwards it is partsnumber 930 110 494 00
The bofore-81 is 930 110 502 00

[mzavada]

Based on those two part numbers, it appears that they are hard lines, correct? (similar to the injector lines) And that would mean I need a new fitting to thread into the WUR, and would then thread directly to distributor?

[Dr J]

The first half of the line is like the steel injector lines. The second half not. I am including some pics which aren't the best since I have a supercharger in the way and a digitally controlled WUR (the aluminum block). Here is the steel/rubber interface first.



This pic is the connection to the WUR ( the aluminum cube). The fuel line has a protective rubber line which is the one you see all cracked. The underlying hose is just fine.



This is a pic of how it would attach to a stock WUR.

[boyt911sc]

Mzavada,

Looking closely at your fuel hose, it looks like it is a little too big and inspite of the clamp/s it will leak. Is this particular piece of fuel hose a fuel injected rated fuel line? These are the fuel line/s between FD and WUR ('81~'83).



If you use the correct size and type of fuel injected fuel hose in conjunction with the right metal clamp like Oetiker 2-ear clamps you should be OK. But I strongly suggest to have it done by someone with experience like Len Cummings (aka BoxsterGT).

Tony

[BoxsterGT]

This is not Hose but Line. Hose is soft & flexible and usually made of rubber; line is semi-rigid and metal or plastic tube.

The correct Line is Polyamide tube and is not designed for clamps of any kind. It is a mechanical fitment over the metal fittings, and requires assembly tools. The fittings have barbs specifically for this Polyamide line.

If you have the original steel part I can re-make this w Polyamide tube. If not, I can supply you with the earlier version that is all Polyamide tube with the correct fittings.

I am retired after 45+ years in the Porsche service business and make up custom Hoses & Lines for most Porsche models for fun and to keep busy.

Please email me for details.

Len at Autosportengineering dot com

[mzavada]

Originally Posted by BoxsterGT

This is not Hose but Line. Hose is soft & flexible and usually made of rubber; line is semi-rigid and metal or plastic tube.

The correct Line is Polyamide tube and is not designed for clamps of any kind. It is a mechanical fitment over the metal fittings, and requires assembly tools. The fittings have barbs specifically for this Polyamide line.

If you have the original steel part I can re-make this w Polyamide tube. If not, I can supply you with the earlier version that is all Polyamide tube with the correct fittings.

I am retired after 45+ years in the Porsche service business and make up custom Hoses & Lines for most Porsche models for fun and to keep busy.

Please email me for details.

Len at Autosportengineering dot com

Hey Len- I didnt see this message until it was too late. I dont have the original (correct) parts on the car.

I've been beating myself up over failing at something so simple, however I've gotten the car to my mechanic, who has confirmed that what came on my car is not what was supposed to be on my car (thanks in part to the thread here, I knew that going into it.) I've bookmarked your site, likely for future use when I start my rebuild. Thanks!

[BoxsterGT]

So..., how did you fix this? Were you able to buy a new part?

Len

[mzavada]

Originally Posted by BoxsterGT

So..., how did you fix this? Were you able to buy a new part?

Len

Luckily my local Porsche mechanic has a stash of old parts, and he had the correct line. I'm in Michigan so my driving season is very short, and I just wanted to get it back on the road. Been contemplating an engine rebuild, so likely will sort through all these annoying little things then.

[72911]

Hey Len,
You must be feeling better. Would you be able to finish my braided hoses and ship them to me? I cant drive my car without hoses right?