Correct fuel line material from tank, or "so that's where the gas smell is coming from" Options

[rjames]

I just took the gas tank to install a sway bar and of course was going to replace the fuel lines that exit the tank and hopefully solve the problem I've had with gas fumes entering the inside of the car. All of the fuel lines that exit the gas tank are plain rubber 50psi max lines and NOT the ones that have braided fabric on the outside. While they look fine, I'm replacing them anyway.

However, less than 2 years ago I replaced the line that runs between the fuel filter and the fuel pump. It's a made in germany fuel line that has the braided material on the outside. It also REAKS of gas as if it's seaping through the hose. The fuel line is less than 2 years old. What's the difference between the braided covered lines and non/braided lines? They both look to have the same thickness of rubber, is one just more heat resistant? (IMG:style_emoticons/default/confused24.gif)

[SGB]

I got no answer, but that is an odd thing.

[dflesburg]

why didnt you run hard lines through the tunnel?

[TheCabinetmaker]

why didnt you run hard lines through the tunnel?

i've read his post three times and don't see anything about replacing the lines in the tunnel. I read he's talking about the lines under the tank.

[swl]

I've read posts here that suggest that using imperial dimensioned fuel lines rather than metric results in a poor seal. Any chance that the leaks are coming from the joints? The consensus seem to be NOT to use braid because it can wick gas - the recall for the engine compartment line replaced the braided stuff with rubber.

[JPB]

The braided lines are designed to handle preasure and the nonbraided ones are only good for lower preasures. If your using carbs, then your lines are under suction which have next to zero preasure. In the tunnel, its nice to use hard lines like stainless or steel break lines like 3/8" thick and only use the rubber ones sparingly. The old clear lines dry up and leak in the tunnel. New ethanol fuels will eat up rubber lines and you will need to change the rubber ones over time. (IMG:style_emoticons/default/beer.gif)

[LS6/914]

I would use a line that has an internal liner that is impervous (sp) to our new fuel blends. Parker hose has a teflon type of liner and has a braided core with a high temp exterior. 250 PSI working pressure when used with AN style twist-loc ends. Hope this helps..Larry

[rjames]

i've read his post three times and don't see anything about replacing the lines in the tunnel. I read he's talking about the lines under the tank.

Correct. I'm talking about the lines that exit the tank, not the ones that enter the center tunnel.

Any chance that the leaks are coming from the joints? The consensus seem to be NOT to use braid because it can wick gas - the recall for the engine compartment line replaced the braided stuff with rubber.

The smelly fuel line in question is a metric size, and as far as I know it's the correct size. The smell is coming from the entire piece of hose, not just at the connection points. I got the lines from the bug parts store in town a little over a year ago. At that time I also replaced the fuel lines in the engine compartment with high pressure german made fuel injection lines, but they are also of the braided type and look to be made by the same manufacturer (They just say 'made in germany').

The consensus seem to be NOT to use braid because it can wick gas - the recall for the engine compartment line replaced the braided stuff with rubber.

What recall? Should I replace the ones in the engine compartment too? Ugh, that would be a pain. Even the enjectors come with braided lines installed on them.

I would use a line that has an internal liner that is impervous (sp) to our new fuel blends. Parker hose has a teflon type of liner and has a braided core with a high temp exterior.

Might have to check for those... Although the existing non-braided rubber lines that were connected to the tank when I pulled it looked fine and were not emitting any odors...

[jk76.914]

Sounds to me the connection at one end- either to the filter or the pump- is seeping. Fuel then is wicking up the braid. On my '76, one end got hard and wouldn't seal any more, but yours are fairly new so that's not likely.

I'm sure that the hoses that were replaced by the recall are high pressure. They have a thicker wall than the braided ones they replaced, and so are fatter- 13mm OD vs. 12mm OD- and are quite pricey. The original 12mm clamps don't fit unless you try real hard and distort them in the process.

I would do the engine compartment. Porsche spent a lot of money on that recall, so they must have thought it necessary.

The only hose under the tank that is high pressure is the one that runs from the pump to the tunnel connection.

[swl]

What recall? Should I replace the ones in the engine compartment too? Ugh, that would be a pain. Even the enjectors come with braided lines installed on them.

The recall was way back when. It was in response to engine compartment fires. Perhaps one of the historians can give exact details but my understanding is that the replaced the cloth braided stuff with rubber hoses that have an extra sheath on the outside and put in hose clamps. I've never seen an original so I can't tell you exactly what the 'pre recall' looks like. Well - if truth be known I probably have seen the original because the recall was done on my car while I owned it. No way I can remember what it looked like though.

Jim is right though - it was only the HP lines that were replaced. Braid in the trunk.

[rjames]

Sounds to me the connection at one end- either to the filter or the pump- is seeping. Fuel then is wicking up the braid. On my '76, one end got hard and wouldn't seal any more, but yours are fairly new so that's not likely.

hmmm could be, although the connections looked good, plus no signs of fuel leaking at the connection points at all. The braided stuff in general now seems suspect to me. Is there any reason that I shouldn't use high pressure lines for non-pressurized runs?

The only hose under the tank that is high pressure is the one that runs from the pump to the tunnel connection.

All lines in the front bulkhead (except for the braided one that I replaced last year that goes from the filter to the pump) are plain rubber that read "50psi max" on the outside. Does this mean that they are specifically FI hose? Seeing as one of them connects the fuel pump out to the hard line in the tunnel, I don't want to be using the wrong lines. I know our cars pump around 30-35PSI, but don't know if a PSI rating above that on a hose actually means that it is specifically a fuel injection hose.

[jk76.914]

Not sure. I do know that I went to NAPA last summer and bought 6 feet of "50 psi max" hose, which was cheap. Less than $1/foot. They also had "hose for fuel injection" which was about 4x the price. I got the lower grade because I wanted a temporary setup to read fuel pressure from the cockpit while I drove, so I didn't worry about "only" 50 psi max.

Personally, I would find the 7 x 13 mm replacement hose that is specified in the recall. That's 7mm ID x 13mm OD. It is smooth walled rubber, no braid. I suppose the NAPA stuff for EFI would be OK, but it was only available in English dimensions. So I guess a quarter inch ID would maybe stretch to 7mm (.276")?

The 7x13 isn't that easy to find. At least in my experience. I'm sure someone else here has a ready source, but I finally bought some from Stoddard, special order from Porsche. And it was pricey. Oh wait. Here is is from Bus Boys-

http://www.bus-boys.com/

Hose - Fuel High Pressure
Genuine Continental 7mm High Pressure Fuel Hose with smooth covering, no outside braided cloth. Our opinion is that this a much better hose than the original braided hoses you find on the some of the FI Buses. Sold by the foot, not the meter like some other places. 12 to 15 feet usually does the engine compartment, supply lines and return lines, depending on the year.

N 20281.12 1974-1979 $4.10 per foot

[Pat Garvey]

What recall? Should I replace the ones in the engine compartment too? Ugh, that would be a pain. Even the enjectors come with braided lines installed on them.

The recall was way back when. It was in response to engine compartment fires. Perhaps one of the historians can give exact details but my understanding is that the replaced the cloth braided stuff with rubber hoses that have an extra sheath on the outside and put in hose clamps. I've never seen an original so I can't tell you exactly what the 'pre recall' looks like. Well - if truth be known I probably have seen the original because the recall was done on my car while I owned it. No way I can remember what it looked like though.

Jim is right though - it was only the HP lines that were replaced. Braid in the trunk.

The recall, which is still active, replaced the injector hoses with smooth rubber hoses & some new clamps, as well as a new battery cover (chopped up from an Audi). None of the other fuel lines were changed. The recall was in 1974 or 1976 - I forget. All the other fabric braided hoses were untouched.

Changing the lines (I'm in the middle of changing all of them, from front to back) isn't really a big deal. Measure, buy, install. BUT.....be sure you use the proper clamps - no something from Adanace/Pep Boys/Whatever. Go to this site for the proper clamps - they ARE important!

www.busdepot.com
Pat

[rjames]

Ok, I'ved decided to replace all of the high pressure stuff with the non braided hose. The 7mm (id) -13mm(od) stuff is available through pellican. I need a few other odds and ends, so I'll get them there.

However, in looking at the fuel injection diagram from Pellican's site http://www.pelicanparts.com/914/technical_...4_20FI_diag.htm
they are showing that one of the plastic lines in the tunnel is 7mm and another is 9mm. Is this correct?
The diagram also shows that the fuel filter is connected to one of the hard plastic lines instead of the gas tank like it really is. Are all of the fuel line connections 7mm or is there one that is 9mm as shown in the diagram? Maybe the problem is that my braided hose with the aroma is of the wrong diameter? (IMG:style_emoticons/default/confused24.gif)

Ack. This thread seems way too long for just being about fuel lines. (IMG:style_emoticons/default/dry.gif)

[r_towle]

two sizes of fuel lines.
The larger one is the feed
The smaller is the return.

If your pump is in the rear of the car..then the diagram is correct from PP
If your pump is mounted up front, then you are correct as far as the filter goes. Filter goes between the tank and the feed side of the pump, so that no unfiltered fuel gets into the pump (hope that makes sense)

Be gentle with the little t/y fitting at the pump, and also look to see that the line changes size from one side of that to to the other...

All the lines should be hard to put on the fittings when you have no clamp at all...then you clamp them.

Rich

[rjames]

Ok, checked everything again last night. My guess is that the larger line (12mm?) that goes from the filter to the fuel pump on my '75 is not fuel injection hose, which is why the gas is seaping through. I also discovered that 1/2 of my clamps throughout the engine compartment are the wrong ones. I'll change those out too.

I also replaced 1 bad injector last year with a new bosch model. It has the fabric covered line on it. The recall from Porsche replaced the braided J bend lines at the injectors with rubber ones. Would Bosche still be putting on fabric covered lines on their injectors if they weren't safe?


Thanks to all who helped get this mess sorted out for me.
(IMG:style_emoticons/default/beerchug.gif)