78SC Replace both rubber fuel lines from exit of Tunnel to Engine

[acapella8]

I want to replace both rubber lines where they exit the tunnel in my 78SC. (My existing lines are dated 3-77!) and have both sprung pin-hole leaks. Not safe to drive in this condition.

Now, I consider myself to have slightly better than the “average bear” mechanical abilities, but fuel systems SCARE this novice track guy.

I have replacement fuel lines on order from Len (BoxsterGT) and as he suggested, I bought a good set of craftsman flare nut wrenches 17/19mm, and so I’m closer to being ready. Read threads on Pelican, but most seem to be generic overview of the removal process fuel line process.

Looking for (if possible) something resembling a step-by-step list for replacing fuel engine lines.
1. Put 911 rear on jack stands, (Drain fuel tank or not)
2. Remove fitting that connect hard-lines in tunnel to rubber-lines at exit w 17/19mm flare nut wrench
3. Start with line that feeds into the top of Fuel Accumulator…
4. Etc..

Now, I think I can tell where the pressure line will attach to accumulator from tunnel fitting. I’m trying to get a mental picture of where the return from engine is and how it goes back to the return line in tunnel.

(I have a Bentley manual, but they all tend to “chop-off” the hoses when they refer to section longer than 6 inches it seems. Also - I tend to overthink and make things more difficult than necessary. (if you haven’t guessed that by now, lol)

I will gladly take step by step pics and post if it will help others with their replacement.

Any (detailed) overview of the process would be most appreciated...

Thanks guys!!

Tom

[boyt911sc]

Tom,

To the replace the fuel lines going to the tunnel at the engine bay area, you need to make the fittings accessible. With the car on a lift or jack stands, the fittings or connections are located just above the transmission mount bracket. Removal of the transmission support would make the removal and installation easier. But requires supporting the transmission when you remove this support. To remove the transmission support, you also need to loosen the rear sway bar and remove the clamps. Leave the drop links attached.

Draining the fuel tank is advisable if you are not comfortable dealing with flammable liquid. Are you also replacing the return line? After you have installed and connected the new fuel lines, pressure test the system before putting the transmission support back.

To pressure test the system and check for any leak, do a FP test run for several seconds and inspect for any sign of fuel seeping or wetting by the fuel fittings. You want to be certain that the system is leak-free before running the engine. If you have any doubt or question, don't hesitate to ask.

Tony

[acapella8]

Tony, thanks.

Yes Len is making up both feed/pressure and return lines for me so I will be replacing both lines.

I know where the pressure feeds into the accumulator. (And this may be a very obvious newbie question, having not been in there yet..)

But where does the fuel "return" line start/begin on the engine as it goes back to the tunnel? I can check PET PDF but was just curious if there is a good photo out there.

Thanks for response.

[timmy2]

Rubber Return line attaches behind #3 runner at the tee on top of the engine. Then runs in parallel with supply line back there.

[acapella8]

Thanks Timmy, and Len already had a great post (just found) here:

Fuel Hoses - 911SC Tunnel to Motor

I can see exactly the two fittings that I need to remove inside the engine compartment to free the hoses that exit/enter at the tunnel.

I have started day 1 of ?? with soaking in PBblaster to ensure I can get them loose.

Stay tuned - will post pics.

[boyt911sc]

Tom,

The delivery and return lines coming from the tunnel for your '78SC have the fitting/connection about a foot out from the tunnel in the engine compartment. The delivery line goes to the fuel accumulator while the return line is connected to a t-connection where the drain for the fuel accumulator is hooked up.

The delivery and return lines connected to the tunnel fuel lines are about 30" to 36" long (approx.). You should be familiar now with these lines. The late SC's have a different configuration for the delivery/return lines than your '78 SC. Just make sure you don't have a fuel leak when you decide to start the engine.

Tony

[acapella8]

Thanks Tony for clarifications on 78 lines.

Len did mention that sometimes factory used conVEX versus ConCAVE at the tunnel, so he was nice enough to send me both, and I return what I do not use.

Saying this forum is great, is an understatement.

I figure I have four connections I have to remove, and I do have flare-nut wrenches. (FA and return connection are being bathed in PB at moment, tunnel comes tomorrow)

Any advice on the removal of fittings at tunnel and top of FA and return fitting??

[BierSlinger]

Hey, sorry to bring this thread back to life. Acapella8, I hope your project went well. I am also in the middle of doing this project. I've removed the rear sway bar and transmission mount as well as the stone guard. I've disconnected all lines that are going the be replaced but I'm having a small bit of trouble pulling the lines through the tunnel. My replacement lines are from Len so he's included a female to female adaptor so that I can attach the old tunnel lines to the new tunnel lines and pull them through but I'm having a bit of difficulty seeing the best way to do this. I know to pull from the front but the lines don't seem to budge easily. Also the line in the engine compartment are held down by brackets that are welded to the body. Any tips on getting the lines out and new lines back in?

Thanks for any insight.

[manbridge 74]

Lots of threads on this, but I pull from rear. Not sure how a guy could pull the 90 degree part through the car. Maybe yours is different. You can lube those lines with something like glycerin to make it easier.

[BoxsterGT]

Bierslinger -

The tabs that hold the lines in place inside the tunnel must be bent up & out of the way. I should have explained that when I sent the lines. Also its really necessary to have a helper to watch the progress with a flashlight and help avoid any snags along the way.

manbridge 74-

If your motor & trans are still in the car, you are wasting a lot of time & effort by pulling the lines out at the rear.

If there is no motor or trans in the way and you are replacing the tunnel lines with rigid tube such as Aluminum or SS, then yes, you can push them through the tunnel from the rear.

Search for "fuel line rescue" posted by krasuskyp. In his graphic way Paul explains the process, even tho he and his buddy did this off the floor on jack stands.

The "coupler" is the key to the ease of pull-thru. Its a fitting first used by Dennis (dap930) to connect the old & new together, and I now include it with my tunnel lines I offer.

You may have one for N/C if you email me.

It really makes a difficult job quite a bit easier to do.

Len

[Ayles]

Originally Posted by BierSlinger

Hey, sorry to bring this thread back to life. Acapella8, I hope your project went well. I am also in the middle of doing this project. I've removed the rear sway bar and transmission mount as well as the stone guard. I've disconnected all lines that are going the be replaced but I'm having a small bit of trouble pulling the lines through the tunnel. My replacement lines are from Len so he's included a female to female adaptor so that I can attach the old tunnel lines to the new tunnel lines and pull them through but I'm having a bit of difficulty seeing the best way to do this. I know to pull from the front but the lines don't seem to budge easily. Also the line in the engine compartment are held down by brackets that are welded to the body. Any tips on getting the lines out and new lines back in?

Thanks for any insight.

Did you remove the 4 rubber grommets? I found that having a helper and Len's fitting made the job very easy. A mirror and a flash light were super helpful for getting a view of inside the tunnel.

[dap930]

Bierslinger -
You will need to remove the two rubber grommets at the back of the tunnel and the two rubber grommets at the front of the tunnel. Buy new ones because these will likely be damaged after being removed. The rear grommets can be pushed out from shift rod coupling access. Cut the existing front lines off where the 90* bend is. Try to pry the front grommets out from the front. If you can not get them out, then push them into the tunnel from the front. Once you can move the fuel line aft some, you can get to the grommet(s) from the front tunnel access hole to cut them off. They need to be removed from the fuel line before pulling the fuel lines through the tunnel otherwise they will get hung up in the tunnel channel.

As Len mentioned the metal tabs(just like the metal tabs that secure the wiring harnesses in place)to the front that secure the fuel lines to the top left side of the tunnel need to be bent back to allow the fuel lines to travel through the tunnel. You will need to remove the center console, carpet and possibly the gear shift lever to get to the front access. I also removed the passenger seat. Some people have been able to do this job without doing all this, but I had to remove all this stuff to get the job done.

[BierSlinger]

I've certainly read this in many posts but this forum and its people are invaluable. It is incredible to see the support that is mustarded up here without question. Thank you for all your insight, everything is much clearer now. I will hopefully be finishing up this job on Monday. I'll keep you all up to date. Thanks again!

[acapella8]

Sorry, that I did not reply sooner - but the true experts have chimed in - let us know how it went and continued good luck.

Tom