Small Fuel Lines

[dwilli3038]

I  am installing a new fuel tank. There are three small lines near the fill tube. Two of them connect to the tank. The other just seens to go to to the outside near the tank. I think I remeber a funel shaped thing there on some cars. It it needed for the car to run correctly? What is it for? What is its proper name? If it is required can anyone reccomend a souce for it?

Daryl
'64 230 SL
Serial # 508

[Cees Klumper]

This is an overflow/venting tube. The funnel-shaped ending on the tube that goes to the outside should be available from regular parts suppliers for around $4. Make sure each of the lines is connected to the proper opening on the expansion tank in the trunk, and that the lines going to the tank are in good condition i.e. not brittle and leaking. This will cause a fuel smell in the trunk.

Cees Klumper in Amsterdam
'69 white 280 SL automatic

[Jonny B]

There should be two small tubes coming from the gas tank (on either side of the fill tube) these connect to a small plastic vent pot inside the right rear fender. The third line is the vent line that goes from the small plastic pot to the funnel shaped vent thing (FSVT as the forum members have named it) that is on the outside of the car. There should be several posts on this - use the search feature, and I think there were some good detail photos on Dorian's site. Cees is correct about being sure the lines are open and not brittle. I had the fuel smell in my car and a whooshing sound and spray when I opened the gas cap, cleaning this all up solved that problem.

Jonny B
1967 250SL Auto

[knirk]

I had fuel smell from the trunk and decided to open up and take a look. Found old hoses without any clamps and a lot of old dirt. Also some rust around the hole going to the tank. The number 3 (outside vent) line from the expantion tank was ripped off just below the hole. So some of the smell is probably from the vented fuel hitting the top of the fuel tank and not being vented below the tank.

From the parts catalogue there are no hose clamps listed - anybody knows if there are suppose to be any?


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Per G. Birkeland
69 280 sl aut 834
Norway

[Jonny B]

There were small hose clamps on mine, and I reused some of them. At the plastic tank, the pressure fit was good enough to hold the rubber lines in place. If you feel more secure with the clamps there, I would say to use the garden variety type that will be just big enough to fit around the hoses, snug them up, not too tight. These are hidden from view so no issue if you are going the car show route.

Jonny B
1967 250SL Auto

[knirk]

Thanks Jonny,
I actually found clamps on the 3 hoses going to the expantion tank and nothing on the rest. I will replace the hoses and try with only these 3 clamps first. Then if there is any fuel smell I will add on the remaining hoses as well.

Per G. Birkeland
69 280 sl aut 834
Norway

[isofast]

As I understand it and please correct me if I am wrong. FSVT small funell shaped thing acts like a road draft tube...as road air is rushing under it at speed the FSVT helps in that it provides vacuuum like suction to the fuel vapor return.Much like an engine road draft tube. If you look under your car you will see three fuel lines two large and one small I am not sure but I think one is fuel supply one is fuel return and one is vapor return to the intake side for a reburn? Please correct me if I am wrong all you old timers but I think the system works like a road draft tube that helps our cars recombust fuel vapor and or trap it into the vapor canister? My FSVT is rock hard was it once soft rubber?

First Place AACA Show Winner 350SL July 2003
I love low mile Mercedes.
1969 280 4spd Papyrus White