Fuel line thread question

palmaceae

palmaceae

Member
Hello all,
I just received my original cast iron sediment bulb that I won in ebay (my current glass one leaks), I also bought new fuel lines and a sediment bulb rebuild kit. Question is what is the best sealer to use on the threads, is it teflon tape or high tack gasket sealer?
Thanks
 
The main line that I am worried about is the line from the gas tank to the firewall, that is where it is leaking now (the firewall side).
Click to expand...

It still doesn't use the threads for sealing. It's the flare end of the line against the filter. The threads just pull the flare tight against the filter. If the flare leaks it would leak between the line and the line hole in the flare nut.
 
As the other posts have indicated, the threads of the fittings do not seal off a fuel leak. It is done by the ferrules on each end of the fuel line that runs from the firewall to the carburetor. The ferrules should crush down to conform to the taper inside the carburetor boss and the sediment bowl. If the fuel line and the ferrules are new you should not have a leak. If they should leak, especially after repeated removals, Put four wraps of white nylon tape around each furrule. Cover both sides of the ferrule, but don't get it over the end of the fuel line. I do this to my fuel line every time I take the carburetor off.

Tom Endy
 
If the taper where the fuel line seats is rusty and pitted it will have trouble sealing.

I have used a copper seal for AC work, they are cone shaped and made of soft copper.
The washer should be large enough to just fit inside the threads (Mercedes used them in the 70s, --and other cars).

They also can be made out of a copper washer , and I have made them out of copper roof flashing scraps.

I like the cast iron bowl, --there are no "vapor lock" bubbles to see and worry about.
When I clean mine I don't bother with the small drain, I just take the whole bottom off that way there is no chance of having a leak at the small drain fitting or breaking it, the lead sealing washer last quite a while unless you tighten it too much and squeeze it out--mine is at least 10 years old

you have to remember to clean it just before freezing weather because if you have water in it freezing can split it open.

Another method is to tin the fitting with solder where the 2 parts meet.
 
Tom Endy said:
As the other posts have indicated, the threads of the fittings do not seal off a fuel leak. It is done by the ferrules on each end of the fuel line that runs from the firewall to the carburetor. The ferrules should crush down to conform to the taper inside the carburetor boss and the sediment bowl. If the fuel line and the ferrules are new you should not have a leak. If they should leak, especially after repeated removals, Put four wraps of white nylon tape around each furrule. Cover both sides of the ferrule, but don't get it over the end of the fuel line. I do this to my fuel line every time I take the carburetor off.

Tom Endy
Click to expand...

The tubing MUST not stick out more than 1/8" or the ferrule will not seat correctly.
 
If you install the ferrules correctly, you don't need the teflon tape. Besides, thanks to ethenol (sp) if you use the tape you will wind up digging it out of your carburetor
sooner or later.

Jack
 
As others have pointed out there is no need for thread sealer. It's the ferrules or tapered end on the fuel line that seals. All the thread sealer in the world won't stop a fuel leak.

I use a little Door-Ease on brass threads. It doesn't do anything to seal but does help to tighten a brass fitting without gauling the threads.
 
Can anybody please tell me what the thread size and type is on the fuel line side of the tank shut off valve and the cast sediment bulb, i'm pretty sure they are the same thread but i need some fittings to make up a "One Off" fuel pipe
Thanks
 
if you are having a problem on the inside line. remove the line and using the filter bowl you are going to install. take soon valve grinding compound and put some on the flair put the line on the bowl a spin the line until you have a good clean seal surface. the problem with most reproductions, them have a seam right on the end of the bowl.
 
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