55.2-59 carb leak

[popeyestruck]

I have a small leak where the brass fitting for the fuel line goes into the carb. Not too much just enough to wet the area. I think its a 1/2 female to 9/16 male . Can I put a nylon or copper washed on the fitting where it connects to the carb? Just trying to stop the leak

[leegreen]

you have a Rochester B ?

If I remember correctly the fuel line itself has a flare, so if it is in good shape might just need tightening. The flare goes into a fitting that threads into the card with a pipe thread, which should get some thread sealant. Paste sealant is better here, if you use tape be careful to not have any extend past then end of fitting where is might shear off and get inside the carb.

newer carbs would have a gasket.

Picture of the carb / leaking spot?

[popeyestruck]

I'll try some sealant. Thanks

[mr48chev]

You want to be careful with sealer around fuel lines. I would figure out what the issue is and correct it.

I'm still digging for Rochester B info as the photo I had was a BV and not a B.

If it is leaking where the pipe fitting goes into the housing you could use a minimal bit of sealer or thread tape. Bare minimum.

If it is where the tube seats in the flare you can try tightening the fitting (use two wrenches). I would pull it apart and check the flare over real close though and make sure there is no dirt in the seat.

Those images from this pfd that has excellent instructions in it. https://www.carburetor-parts.com/ass...r-b-manual.pdf

[popeyestruck]

Its leaking where it goes into the carb body. I didnt realize it was a pipe fitting. Its bottomed out with no threads showing

[dsraven]

if the adapter fitting is leaking where it screws into the carb it could mean that it has been screwed into the carb body too far in order to get a seal. pipe threads are a tapered thread so it is like a wedge. the carb body is aluminum so if it were me I would check the carb body for any tiny cracks caused from the fitting being wedged in too far. the fitting itself is a fairly common one so you could source a new one before doing anything, so you have it on hand if need be, then unscrew the flared fitting and get the supply tube out of the way, then unscrew the adapter fitting from the carb, check for any small cracks in the carb body and for any bad threads in the carb hole. if,none and the carb end of things looks all good, check the adapter fitting threads and look for any cracks etc. check the flared connection for distortion or anything that may cause a leak. if all good decide if you want to re-use the fitting or install the new one, use some thread sealer on the pipe threads and screw it back in. if using the teflon tape there are different qualities of the stuff. in Canada the white stuff is generic and not to be used for any natural gas or propane fuel connections by code. there is a thicker style used for this purpose and it is either pinkish or yellowish color. I would use the natural gas teflon tape if I were to use that method. another method of pipe sealer is the thread sealant compound, or pipe dope which is a paste. some say to use it over the teflon and some say to use it all by itself. it is a lubricant as well as a teflon based sealing compound.
since brass and aluminum are both pretty maleable you might be better served to replace the brass fitting in case it has distorted by being overtorqued into the carb. the problem with doing this is that the flared fitting is also maleable and usually the sealing surface if the flare has become slightly distorted to cvonform t the brass fitting's sealing surface and vice versa. a new fitting may fit into the carb and seal well but the flared fitting may become your new leak.

[dsraven]

k, just texted with a journeyman plumber. he advises a new adapter fitting because pipe threads actually conform or slightly bend as they are tightened up, in order to create a good seal without a sealng agent. then also check the condition of the sealing surface of the flared tube end and reflare or replace the line as you see fit. you could google the pipe thread sealing theory if you want here. scroll down to the npt nptf section
https://www.industrialspec.com/about...thread%20roots.

use a few wraps of the thicker teflon tape that is for gas lines etc, not the white stuff but usually, around around here anyway, gas fitting tape is yellow or pink. don't use the pipe dope as it is not rated for liquid fuel and will possibly just wash out of the connection causing more grief if it gets inside the carb.
the link above tells how to properly tighten a pipe fitting if curious. pipe threads rely on the threads contacting each other to form the seal. the teflon or dope is a lubricant really so it makes it easier torque the fitting without galling the metal parts. if that makes sense.

[dsraven]

if taking the carb off for some reason I would suggest a new fiber gasket under it to help absorb the heat from the manifold and lessen the chance of fuel boiling off after a hot engine is shut down. this is pretty common and the reason why some old cars and trucks can smell like gas after they were turned off and also why some can be harder to start, because the fuel pump has to re-fill the carb.
checking the threads inside the carb where the adapter fitting is screwed in is also recommended. just in case they are also deformed from overtorquing. the fitting shouldn't really be bottomed out there.

[dsraven]

anyway, post up your findings and how you fixed it so someone else can also benefit. pics would be great.
have a Merry Christmas, your truck looks great. I wished mine was close to getting done, I made a lot of custom changes and simply have had a full schedule-for the last 15 years! lol.

[mr48chev]

Pull that fitting out and make sure that it is the correct fitting. Meaning that someone may have swapped fittings for one that is intended to use a gasket and bottom out with the gasket between the nut part and the body of what it goes into. The fitting should have tapered pipe threads and the hole should have tapered pipe threads.

The fitting will screw in but won't seat properly or seal if you have the wrong fitting.

That is just something to check and make sure that you have the correct fitting so you aren't fighting it.

[dsraven]

if you get to it, and decide to take the fitting out, then aren't sure if the fitting threads are tapered or not, take the fitting to a hardware store and compare the threaded section to a pipe thread fitting. it should screw in a bit easily then get tighter as you continue. the fine thread bolts would have a different count of threads per inch so they wouldn't screw into a pipe fitting
if you have a pipe threaded nipple or other fitting with the external pipe threads you can do the same test on the carb.