Ferrule 101

marc hildebrant

marc hildebrant

Well-known member
Group,

I was replacing the gas line from the sediment bowl to the carb and I can't figure out how to assemble the ferrule correctly.

I but it on the gas line and inserted it into the carb. Then tightened down the nut. Pulling it out to see just where the ferrule went, it was all wrong as it was just part way onto the pipe. It was crimped down and could not be re-used.

How do you install them correctly on both the carb and the sediment bowl ?

Marc
 
Hi Mark, the way I have been doing it is to slide the nut onto the pipe, then slide the ferrule on . It should be a snug fit. Then push the pipe completely into the female until it seats solidly. Then slide the nut and ferrule into place and tighten the nut. If the ferrule is larger on one side, put that side toward the nut and the smaller side to the female connection. Tighten the nut so it very tight so as to collapse the ferrule and make the seal.
 
Art,

Thanks for the comments. When you push the pipe into the female part so that it stops and then tighten down the nut...does the ferrule to pipe distance become "less than 3/16" as the books say ?

Marc
 
Some folks have suggested that you run a bolt into where the filter screen goes. Then push the line and ferrule in so the end of the fuel line is up against the bolt and tighten. This will leave the end of the fuel line slightly back from the screen on the filter when it is re-installed. You don't want the end of the fuel line jammed up against the filter screen.

After repeated times removing and replacing the carburetor as I do because I am constantly road testing rebuilt carburetors, the ferrules get whacked out of shape. Mil spec would dictate you replace the ferrule each time. I put four wraps of nylon tape around each ferrule each time and it seals off any leak. You have to be careful not to get the tape over the end of the fuel line. I have been doing that for years.

Tom Endy
 
Group,

These simple looking things are giving me grief !

I put a bolt into the screen filter hole on the Zenith Carb and installed the ferrule/nut. The ferrule was set back nice (1/8) inch, but I couldn't get the nut to really snug down the ferrule onto the tubing.

The section on the cast iron sediment bowl was worse. Even though I tightened down the nut, the ferrule wasn't getting crimped to the tubing.

I looked at the nuts that bolt to the carb/sediment bowl and believe that they are hitting something inside as the threads on the nut are getting rounded smooth, thus I can't get the ferrule to grip the tubing.

Gad !

I'm using the old line again and again and it's just barely holding. I want to replace this line as its where I "think" the vapor lock is occuring. The new line has a slightly different shape and I'm thinking that it may help my vapor lock as it would be in a different part of the engine air stream.

HOW DO YOU INSTALL THESE THINGS !!!!


Marc
 
Are you by chance using a nut with a built-on ferrule? It will have a cone shape on the end.I had somebody complain they could not get the nut to go in more than a few threads,and the ferrule would not compress.They were trying to use a combination ferrule/nut,with a ferrule on the line.Neither part crushed,and I was able to just remove the ferrule and tighten the one piece unit.
 
Keith,

I am not using a combination setup. I have a seperate ferrule and nut. The problem seems to be that the nut isn't crushing the ferrule at all.

Marc
 
Group,

I was able to solve this problem with the gas line ferrules.

The new brass compression nut that I first used had just threads on the nut, while a different type that I got later, had a small shoulder after the threads and before the end of the nut. With this "shoulder" on the compression nut, the ferrule was crimped onto the tubing with very little force from turning the nut. What it looks like, is that the shoulder after the threads allows the compression nut to enter the carb and sediment bowl further and thus allows the ferrule to work. Without the shoulder, the nut would not enter the female part enough to squeeze the ferrule.

No gas leaks with a modest tightening of the nut.

Marc
 
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