This is the side-inlet Quadrajet on my 1980 4.1. I recently replaced the inlet nut and it is definitely secure. I did not cross-thread or strip it. After I shut the car down yesterday I noticed a slow, steady drip of gas where the yellow dot is in this picture. I think it's coming forward under the flat underside plane, not dripping down the front surface visible in the picture. Where do I begin looking for this leak?
Wow! Fast response! I read or was told that teflon tape is a bad idea there because fuel will dissolve it. I used anti-seize, which I'm sure would also get dissolved by fuel... Wouldn't threading it in until it's tight prevent fuel from getting past the threads?
Hey that gas disolving the teflon tape is a real possibility, hadn't thought of that, but if you put it only on the threads it may work. Or at least if it stops the leak you will know that is problem.
Something to consider here is the possibility that the factory gasket is missing. This gasket is a white plastic ring, about 1" in diameter, which goes on the end of the filter holder. If this is missing, there is nothing sealing the fuel entering the bowl from the pump from the outside. It is easy to miss this seal, and even easier to damage it when installing the part. These rings are part of a rebuild kit, and many are available aftermarket, if you know what you are looking for. You are correct about the use of teflon tape, but not for the correct reason. It is not recommended because it is easy to tear during installation, and the pieces, which are NOT sensitive to fuel can therefore get into the bowl, causing havoc. Look for the seal, and replace it if missing or there is any doubt regarding its integrity. If you cammt find a seal, teflon tape, if installed correctly will work fine, especially considering the alternative: an engine fire.
You know, I think I do remember a white plastic ring and I don't think I installed it. ou: I'll have to take it apart and have a look.
Ok, I've just checked my parts department (the pile of boxes in my basement) and the plastic ring is AWOL. Either it's in the carburetor where it's supposed to be or it's gone forever. Tips on using teflon tape properly to avoid having any break off in the fuel filter? I'm guessing I just have to make sure it doesn't go all the way to the end of the thread, and make sure it's wound in the correct direction to avoid unwinding as the fitting is tightened.
We have the correct seals for the end of the fuel filter housing, not much more than the cost of a postage stamp. I would NOT under any circumstances use teflon tape on any of the fittings or threads. It is the #1 cause of carburetor "issues" that we see here. It does NOT dissolve in fuel, but "snakes" it's way into the carburetor and plugs up tiny passages, or gets stuck in the needle/seat assembly causing flooding.....Cliff
A couple of comments- 1- Anti-seize will not act as a sealer. It will give you a false sense of when something is "tight" and can lead to over tightening a fitting. This is especially true in the case of a steel fitting going into an aluminum housing like a carb body. You might have created a small crack in the housing by accidently over-tightening the fitting. 2- Teflon tape will work fine on the fitting as long as you exercise reasonable care in applying it. do not wrap it around the tip of the fitting, where threading the fitting into position will cause it to rip and tear and float free as described above, allowing it to muck up the internals of the carb. Wrap at most 2 turns around the straight portion of the fitting leaving the first thread uncovered. Make sure you wrap it properly, counter clock-wise, and you won't have a problem. 3- Some installations also require a flat fiber washer at the shoulder area of the fitting where it contacts the carb body. I couldn't see in the picture if you have one or not.
Cliff, do you have the correct seal for the side-inlet configuration? I ordered the inlet nut from you and that was a complication. Tom, I used the anti-seize only to prevent seizing, which seems inevitable for fuel lines on my vehicles . I will have to inspect the housing for a crack. That would be awful. I definitely do not remember a flat fiber washer.
I agree you are probably missing the gasket on the end . and you should change it when you change the fuel filter every time. the gasket gets hard and can cause you to cross thread the filter nut then you are screwed gasket is less than a buck unless you go to checker auto parts . they dont think it exist . :laugh:
Teflon tape has no business on a straight (non-tapered) thread. This type of fitting is designed to seal on the face behind the hex, not the threads themselves. Relying on the tape is a band aid fix and as Cliff said causes more contamination issues than anything else. Don't mess with fuel. If there is any time to do something the right way, this is it. Devon
You should be able to get the white nylon 1" round gasket in the HELP products section at any major auto parts store. Ken
Is it the same for the side-inlet as the more common front-inlet? The fitting is a different diameter.
Something I just recently found on my carb was the aftermarket replacement housing for the fuel filter had cracked where the molded steel line meets up to seal off. The crack was inside and because it would give when the molded line was screwed in, it never sealed properly. I had a slow fuel leak from the same area you do as a reult. Luckily I have a dozen or so spare Q-jets I was able to rob one from. That replacement one was junk. Looked nice and brand new, but the metal was soft compared to the original and it cracked really easily! I'd take a pic if I could, but I'm away from home. Basically, detach the molded steel line going into the carb and look up into the fuel filter housing. That area where the two meet up and seal was cracked on one side so that the steel line could never seal off correctly.
69GSCAL, you're saying that the inside of the inlet nut aka filter housing cracked? That is, the bright brass thing in this pic? I'll have to check that too.
We have the correct gaskets and the fittings in stock. Always best to call the shop directly when ordering parts, that way we always get the correct item shipped out the first time.....Cliff
That's it, the shiny copper/ brass housing you have your hand on. Looks pretty, but it seemed to me the metal was much softer than the originals I have. What happened was when I found the leak I pulled the housing to make sure the plastic washer was in there. It was. When I put it back together it seemed like the fuel line just never got tight. It was screwed in the same depth it normally does on my other carb (I was trying out a new carb), but it ust wasn't tight. Pulled the housing back off and looked down to see the part where the line and housing seal off was cracked. replaced with an old rusty one and no more leaks.
It was the plastic washer/gasket. I went to the nearest chain parts store to get one in the Help! section. I brought the old inlet nut to test-fit. When I got there I found them quickly and opened the package to try one on. It seemed like a tight fit and it didn't want to stay on. That's when I noticed that the old one was still stuck on there! ou: Having opened the package, I bought it in spite of not really needing it. Might as well use a new one. The old one was clear and grimy and not something you'd notice there unless you were looking for it. I guess I never looked for it. In this picture it's still attached, and a bright white new one is next to it for contrast. Thanks everyone! :TU:
