the flyin' scotsman

Need a large block of steel to make the mold and then a high temp oven; hmmmmm going back to my original plan.

Bill Ball

Oh. I have the old kinked one from my 89. I just cut it open - it has a rubber sheath over a semi-rigid plastic inner tube. It is not simply a "liner". It is the fuel line. The rubber cover is a loose fitting sheath. The inner tube is labeled Aaflex 11? (last number or two cut off). We know the design changed from the earlier style. Wonder why.

The metal end fittings extend far INTO the inner tube. There are no external clamps or crimped fittngs on the tube or the sheath. The plastic (or whatever semi-rigid material) is pressed OVER about an inch of the metal fitting, over what look like barbs. Quite different from the earlier design, as shown in DR's pics in his earlier post.

My wife took off for the week with my digital camera or I would shoot some autopsy pics.

ROG100

Braid on a hose is there as an abrasion protection and is also very flexible and will not stop the hose kinking if it needs to. Think of it as a piece of netting over the hose ID.

New hose will maintain a bend rad, however as it deteriates with age and use it will kink or crack.
I also want to see the surface of the hose so I can visually inspect its condition.

Martin in the UK contacted me with a possible hose replacement that can achieve the min bend rad.

I am going with the re-route of the original and using the correct EFI hose and correct EFI clamps.
There is absolutly no point in using something that is way beyond the design criteria.

H2 you keep mentioning crimping - this is a method where the collar over the hose is dimpled and traps the hose to the fitting. This means that the entrappment is in selected places and not on the complete circumferance of the hose - potential leak path.
The only way to correctlly get a 100% entrapment is to swage the collar or use an EFI clamp designed for the job. Porsche used the clamp on the other hoses adjacent to the U hose.

These hoses are made up of seperate layers that contribute to the overall integretity of the hose depending on its deign parameters. This also provides for redundancy if one layer fails.
SAE 30R9 is the standard designe for EFI hoses and I would prefer to trust all the testing and life cycling expended to prove the hose for this specific design than go off and try a different and unproven hose/design.

Remember the hoses are failing because of the effects of heat and aging on the older technology material. The hoses used to meet the EFI requirement are much better than the ones designed 20 plus years ago.

The fittings never failed and were only push fit - no crimping, swaging or clamps. So the fitting will work fine without the clamp. The clamp is added insurance and if you want to be extra carefull wire lock it in place so it will never loosen like we do in aerospace.

Just my 5c

Roger

ROG100

I will be cutting up an 87 U hose over the weekend to look at the makeup.

H2

"H2 you keep mentioning crimping - this is a method
where the collar over the hose is dimpled and traps
the hose to the fitting. This means that the entrappment
is in selected places and not on the complete
circumferance of the hose - potential leak path. " ROG100

Rog,

I hadn't thought of it that way....what you say makes sense. BTW, for us ****/paranoids, there appears to be enough room on the hose "nipple" to place two (2) EFI clamps that are aviation wired...and maybe a little gas proof sealant.

Harvey

Steve J.

Another solution would be to find a similar U shaped fuel hose used on some other model car that could be adapted to our 928's. I found a Volkswagen fuel hose with the U bend I needed to replace the section of hose under the throttle cable pulley on my '87.

H2

Steve,

Now that's getting creative! If we could find a fuel hose with an acceptable bend and length to replace the rear U-shaped fuel hose, we'd pretty well "be there." I wonder if one of the hoses you show would work for the shorter S4 hose? Inside diameter would have to be just right. But it doesn't look like these hoses would have the crushing problem on bending that has been a concern. Good work! Do you have VW parts numbers for these hoses? Have you installed one of these yet?

Harvey

Steve J.

Looks like it's been about five years. I looked at it yesterday - it seems fine. VW p/n P/N 037-133-990-2. A Jetta fuel line I think.

ROG100

Steve,
That is great news. Did you use the original fittings and just clamp the hose in place with EFI clamps?
Roger

ROG100

Just ordered a dozen - yipee we found a fix.

DR

Roger,

FYI, that appears to be the return line on the 87 that he replaced. It looks to be the one that attaches on the OUTPUT of the pressure regulator and goes to the fuel return console (hose 928.110.359.04) That hose is typically not under pressure and probably not rated for Fuel Injection pressures (I doubt the VW version is either). Better check to be sure before you start sending out replacements for the odd U-shapped hose for the HIGH pressure interconnect between the Pressure regulator and diaphram dampner.

The later 88-up version (08) looks like the one pictured below.

Maybe Steve can verify which hose he replaced to be sure.

ROG100

Dave,
You are right thanks for the headsup - I saw the U and got all excited.
Order cancelled.
Thanks,
Roger

Back to the drawing board

Steve J.

That is correct - it was the return line - held on with clamps as shown in the PET drawing. That one may also be NLA. But somewhere out there is a high pressure fuel line for some other make/model car already bent in a U. We just have to find it.

the flyin' scotsman

'Just when you thought you were out they drag you back in.'

Roger........I molded some EFI line around a spring and it did not kink and then sprayed with some high temp polyurethane. Once fully cured I'll get the spring out and see the results and post.

auzivision

Keep working it Roger... you'll get it right and the world will be knocking at your doorstep. Until then we’ll watch with keen intent… just let us know when it’s go time!Keep working it Roger... you'll get it right and the world will be knocking at your doorstep. Until then we’ll watch with keen intent… just let us know when it’s go time!