jayc67

OK, after reading the near fire thread it's my New Years resolution to replace the fuel hoses on my 87 S4

My paperwork shows it was done 13 years ago.

I'm having heck finding exactly what I need to replace, sorry for being too dumb to find it in search. I promise I looked

I know there are 2 U shaped hoses on the front and back, but not sure what else.

Anyone have a pointer to a document or something on what pieces I need to be concerned about?

Thanks very much, as always.

Rob Edwards

This schematic is a repost of something Heinrich posted a while back and is a great diagram:



There are 4 lines to rebuild or replace:
1- the front straight piece between the fronts of the fuel rails (928 110 269 01),
2- the U-shaped rubber portion of the inlet line by the passenger side shock tower (928 110 367 15, though the rubber section is not available separately)
3- the U-shaped short line between the rear FPR and left rear fuel damper 928 110 271 02, no longer available as far as I know..)

and

4- The line from the FPR to the fuel cooler . On your '87 that piece is different from the other S4+ cars and is 928 110 359 04.

So you could spend ~$300 for the 4 fuel lines from Porsche (if you could get them) or you can buy Roger's kit and rebuild your old ones. (Greg Brown also has a new set of these hoses done with Goodrich hose and custom fittings, I don't have pics of these yet):


#1 is self explanatory.

#2, rebuilt with Roger's kit

Note that this rubber loop is longer than the stock piece- it needs to be a little longer to make an acceptable radius.





#3 and 4- Two views of the rear 'U' and the FPR-cooler lines:





Here's a shot of the '87 configuration showing the different FPR-cooler line (Forgot whose pic this is, sorry if I'm infringing on any copyrights...).

jayc67

Wow, that's fantastic, just what I needed. Thank you so much.

Stromius

Jay - Very worthwhile to have the peace of mind. I found my return hose(#21 in pic above) was dried and cracked and broke in half as I flexed the hose. It's not a very hard project. I left the dampers and hard lines in place and added a fuel pressure gauge at the same time.
my pics: http://reutterwerk.com/forums/showth...ght=fuel+lines

jayc67

Mine LOOK nice and pliable like you mention in your link, no visible cracks at all, but after so many people saying it was a pretty easy job I think I should go ahead and do it.

Pressure gauge is a good idea, I may look into that. Thanks.

blitz928

Another tip, the feed line that is on the pass. side cam cover with the small section of rubber that bends and goes back to a hard line and ends up under the front damper. I've found it best to leave that line in place when you cut off and replace the rubber section of line.

jayc67

Couple of things.

First, thanks everyone for the tips.

Second, I did the front 2 hoses today. I would have sworn I did them years ago but they were stamped 86. That said, I have to say they were in perfect condition. I wouldn't hesitate to use them again (other than I had to cut 1 of course). In fact the front one I'm keeping as a spare just in case. It's absolutely perfect; no cracking, very pliable, no swelling. Truly looks new. The other front one was very nice as well. The hard plastic inner lining was in very good shape when I cut it off and the rubber showed no cracking when I bent it back and forth. I was surprised, but the peace of mind is worth it.

And my questions of course:

I didn't do the back 2 hoses today. Does the MAF need to come off to get to these? Looks like it would be better to take the whole assembly, regulator and damper and their brackets, out to do Roger's hose kit.

And the kit, one clamp sufficient for each junction? Roger's zip loc was full of clamps but I didn't know if some were simply extra or what.

Thanks so much, as always.

blitz928

Yes you should remove the MAF, You'll need to take off the pass. side fuel rail cover and you'll need a long flat blade screwdriver to reach the clamp, at the base of the MAF.

Yes, one clamp is sufficient at each junction.

You can take the damper and brackets off, but it's not really all that difficult to just remove the hoses. I took everything out when I did mine because I replaced the regulator and damper as well. If I wasn't doing that I would have only removed the hose and left the damper and regulator in place.

Hilton

Just to add to this thread - for the 87 S4, there's a 5th line in the engine bay. Available from Porsche, part no. 928 110 359 04.

You can see it in the last picture Rob posted - its the one the screwdriver is tightening the clamp on.

Later years replaced that rubber S-shaped hose with hard line, until the rubber section going to the fuel cooler. In the 87 S4, there's two rubber sections on the way from the Fuel Pressure Regulator to the fuel cooler.

So the total S4-onwards count is:

1. Connection to Fuel Cooler
2. U-shaped hose between pressure dampner and pressure regulator
3. Front Porsche hose between fuel rails
4. Front right pressure line from firewall to hardline off front pressure dampner
5. (87 only) additional S-shaped hose from return side of Fuel Pressure Regulator - 928 110 359 04

The S-shaped one has tight enough radii on the bends that I wouldn't consider using fuel line stock - the Porsche part is les than $10 anyway.

jayc67

OK, finally some nice weather here and back to these 2 rear hoses.

As is my luck, it's a nightmare.

So..... I have an early '87 and I learn that for some reason they decided to make this one a real Rube Goldberg device.

There are 2 hoses in the rear as Xlot describes. They meet at a "coupler" thing that shares the bracket with the throttle body cable pulley.

Are BOTH of these still available and if so does anyone have the part numbers?

The short S shaped one with the tight radius is 928 110 359 04, thanks Xlot.

What about the one from this "coupler" to the fuel cooler?

This one has the funky swaged on rubber section to a hardline and there's no way to just cut the rubber hose off and clamp on new hose.

So I guess I will need to buy both of these hoses/hardlines to finish this "5 minute job" .

And, as with the front 2 hoses I'm kind of annoyed that I started this, they were all in perfect condition before I started cutting them off to replace them. But at least I'll know for sure and won't worry about it.

If anyone could help me with the part number to that other hose I'd appreciate it. I can't seem to find it anywhere, all of what I have shows the single line setup.

5 minutes turns into 5 days

blitz928

I took everything off including the "coupler". From the bottom of the regulator all the way to the fuel cooler. Then replace everything on a work bench. I used the same fuel hose from the kit SAE 30 R9, 5/16 ID and just made it a bit longer to compensate for the bends. Keep the old bent hose and curve the new hose to match, just don't allow it to kink. IIRC my new hose was around 1.5" longer. Reuse the clamps after the regulator as they are a bit smaller.

My hoses were in good shape as well, but I feel better that it was done.

jayc67

How do you get the old rubber off? It's swaged onto the hardline with some kind of metal coupler.

There doesn't seem to be anything to slip a new hose over.

Rob Edwards

I'm not sure about the availability of both those hoses ( I accidentally bought a 928 110 359 04 when I was a newb. It's hiding in the garage somewhere, so at least that one may still be available- from me if nowhere else- let me know!) but if the other section is NLA you can do the SAE 30R9 thing, yourself, or if you get stuck Greg Brown made me a single hose that runs uninterrupted from the fuel cooler to the FPR. It's the long one across the top of this pic:

Rob Edwards

Here's a good thread with pics on dremeling off the 'cuffs' on the old lines:

https://rennlist.com/forums/928-foru...line-kits.html

jayc67

OK thanks. I think I can make that one work, but the S shaped one I'll have to order.

Roger says they still make that one, 8 bucks or something. The bend radius is just too sharp to not kink the hose in the kit and there's no good way to reroute it without running up against things.