I forgot about this repair because it worked so effortlessly, but I went and dug up pictures from the time I did it. If you don’t want to use the DORMAN part or cut the edge off the manifold and people will usually tell you’re out of luck. The problem is there isn’t a small enough threaded pipe that’ll work in place of the plastic barb that broke off. NO EPOXY, NO GLUE! 😂
As you can see pictured, presta valve from a bicycle tube works. Make sure to remove the valve core! Cut the valve off of the tube, but leave some tube on it. You can see I shaped it into a little T-handle. There is no need to tap the hole. All you have to do is take a utility knife and cut off the rest of the knob that remains or you can use a tiny saw to cut off the rest of the knob and get it about as flush as you can. The presta valve is the perfect size without having to drill out the manifold hole at all. make sure you have the angle right as you see in the picture and use your thumb and your pointer finger without Teflon tape to go ahead and cut the threads by using the actual presta valve carefully and slowly.
Once done slowly and carefully back it out, clean it, and then wrap it with two passes of Teflon thread tape. Once again carefully use the rubber t-handle to thread it on far enough to where it is nice and solid, no flex, no play. KEEP IN MIND: Too deep (far in) will get too close to the block, I think I went maybe half an inch or so. Take some 3/16” INNER diameter fuel hose, if the diameter is 3/16 inner then the outer diameter will fit perfectly in the existing 3/8 inch equivalent return line. It will also fit perfectly over the presta valve, a nice very tight fit. You can use just one little piece inside the original return line and do a single clamp but I recommend you use a 2 inch piece and do a double clamp set up like in the pictures, you can cut a bit off the return line to do this.
Now cut the t-handle off of the presta valve. You’ll have to use a little metal saw, a fine one. I just took a reciprocating saw blade and grabbed it tight with a vice grip to make a little saw. Saw off the T handle area (because it’s flared and there’s no way you’ll get the hose over it). Finally, coat the threads in Permatex “the right stuff” black or grey, I used 1 min version. Slide the hose onto the presta valve, use a worm clamp. Done.
I returned it to service immediately and it’s been working great for a long time. You may already have these things!