79SC fuel tank related vent hoses

Robey5 · 11-30-2018, 06:43 AM

Hey y'all...

One of the "to-do" items on the 79 is getting the brakes cleaned up; and I am getting into the front left corner first.

Incredible that this car has stock brakes and stops on a dime. Even though the piston seals have been destroyed; and there is a bunch of crud all over the place, this car's braking performance is quite solid.

On to the question: as I was cleaning the wheel well, I found a couple rubber braided hoses that I BELIEVE are supposed to (somehow) be attached to something to vent the gas tank through ... a charcoal container (maybe). ... however, I do not know where this container IS - or what it looks like. I know why I can smell gas now.

Any input on where these hoses are supposed to connect to?

et cetera · 11-30-2018, 07:49 AM

Is that the line to the overflow for the brake fluid reservoir? There should be a line like that that connects to a container just above the washer fluid tank.

Also, what are you using to clean your wheel wells? They're looking great. I'm planning on doing mine over the winter.

Robey5 · 11-30-2018, 08:38 AM

etc:

That seems to make a little bit of sense: but these hoses are two different diameters, and are connected with a (metal) tube which is at the top of the wheel well, toward the front of the car near the 'strut' housing (yeah; a picture is worth a thousand words here - I will upload one later). what is seen here is only 'disconnected sides', the other side has the metal clamps on them, the larger diameter one reeks of gas, and seems to go near the washer fluid reservoir; the smaller diameter hose looks like it is supposed to go toward the cabin, and does not smell like anything (ie: brake fluid stings the nostrils...)

Regarding the "what" I am using to clean the wheel wells: a hot hose and a bucket full of hot water and dawn. I am not intending to remove all of the undercoat, but it is an unintended affect of this little project.

I am sure someone who has done a full tear apart of their SC will be familiar with this pair of hoses, and may be able to guide me in the right direction...

et cetera · 09:53 AM

ohh, I got ya. here you go... What's this tank for?

I think the brake fluid vent just dumps on the ground. I thought it had a catch down there as well.

Brian Cameron · 10:53 AM

Just replaced all this on my wife’s 79SC.
- Tank vent hose goes to a metal tube just below the fuse block.
- That tube exits at the wheel well and from another hose connects to the overflow container in the wheel well.
- Another hose goes from that container into the footwell at left of the pedal cluster (via another metal tube IIRC).
- Another hose traverses to the right to meet up with yet another metal tube at the shifter tunnel.
- That tube travels inside the tunnel and exits at the rear where the other fuel lines and clutch cable come out.
- Another hose snakes up into the engine compartment along with the fuel hoses and goes to the right along the firewall, to connect with the carbon canister beside the oil fill pipe.
- a thicker hose runs from the carbon canister to the airbox (intake)

The idea is that any gas fumes from the fuel tank will be absorbed into the charcoal in the carbon canister, then get sucked back into the intake when the engine’s running.

Hope this helps

Robey5 · 11:40 AM

Ok ... it seems that I am missing

911-201-077-02

And, the car is running fine. I think that I can buy one and install it down the road. The question is ... why would someone just remove this tank from the equation and not care? I am a fan of not smelling gas fumes.

Brian Cameron · 11-30-2018, 02:11 PM

Me neither, and there were plenty of fumes as most of the hoses were pretty much rotted away. The tank was there, but not connected to anything.

Who knows, maybe yours fell off somehow?

chrismorse · chrismorse's Garage

Well, this is a fairly embarrassing mistake I made on my 308, that is directly applicable to most cars, including our Porsches.
I overhauled the Webers and was "cleaning up" the engine compartment, replacing the hoses, temporarily removing the evaporative and emission stuff, trying to get the carbs dialed in. I then left for my first Ferrari club event. 200 miles down the road, All fine, car ran great, until I was climbing the road before the descent to the Golden Gate and the car started to slow, seemingly running out of gas, ease up on the throttle, car picks back up.
So, I ended up missing my first Ferrari event to do a roadside fuel pump replacement, which didn't fix the problem. Cracking the fuel tank cap and hearing a big hiss, was a humbling A-HA moment - I had hosed myself by cutting off the fuel tank venting, choking off the fuel tanks admission of make up air for fuel used.
FUG
So, my friends, you must maintain fuel tank venting.

Chris

Robey5 · 12-05-2018, 11:50 AM

I placed an order for 911-201-077-02 - the front charcoal tank. As this car has presented itself as a case of deferred maintenance (some forms worse than others); I bet that this tank was removed for whatever reason (ie: the car wasn't running correctly) OR, a bump was hit at some point and it fell out. Either way, I'd love to see more pictures of HOW this thing is installed up there -- can anyone post more pictures of this contraption in action (specifically how it attaches to the back of the head light bucket or wherever)?

Brian Cameron · 12-05-2018, 04:28 PM

Mounted, it looks like this:

Brian Cameron · 05:07 PM

Found this pic from another pelicanite, but not sure if it was for an SC. Looks like the top of the overflow tank hooks into a bracket at the top of the headlight bucket, a little hard to see in this pic but it’s there. The bottom of the tank then bolts down to the other bracket, lower down on the headlight bucket.

Notice the looped hose, the tank was bypassed entirely here!

Brian Cameron · 12-05-2018, 05:09 PM

Here’s the bolt etc shown in the katalog:

Walt Fricke · 12-05-2018, 06:21 PM

Your brakes work fine because the seals that count are fine. What you are looking at is the dust boot. Those do fry, but they don't directly affect braking. Over time more wear might happen to the pistons, but the hydraulic seals are down inside the cylinder. Think of them as being like a piston ring, but set into the cylinder instead of the piston, and made of rubber (well, something pliable). You can't see them until you disassemble the caliper by pulling the pistons out.