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Quadrajet fuel filter leakage

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Old June 29th, 2014, 05:55 PM
  #1  
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Quadrajet fuel filter leakage

Does anyone else have this problem? My original carb on my 71 started to leak at the fuel inlet. I tried to tighten it and yep- you guessed it- stripped the carb body. I had a lot of money in this carb so I sent it across the country to a carb shop in Calif. to have a helicoil installed. Guess what ?? They installed it crooked!! No doubt about it. I sent it back to them-(another $60.00 shipping there and back) and they didn't do anything. It wouldn't seal because the small nylon gasket inside the carb was crooked. I sealed it up w/seal all on the threads and it worked until I bought another carb off ebay. This one is great. I put it on last year but now... yep, leaking at carb inlet. This carb, though the same # as my 1st one, has a nylon gasket that seals at the outer end of the fitting, where it gets bigger in diameter by the hex. I took the fuel line off at the fuel pump and was very careful and took the fuel filter housing off and everything looked fine but still leaked. Then I took it apart again and put the trusty seal all on it and appeared ok. But now it's leaking again.. Any suggestions/advice? This should be a easy deal but I can't seem to get past it. Thanks, Greg.
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Old June 29th, 2014, 06:25 PM
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Greg, some may disagree with me,
but I use teflon tape on the threads
of the filter housing.
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Old June 29th, 2014, 09:02 PM
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As you found there are two different styles of fuel inlets.

I have had multiple QJets over the years and I have never had a leakage issue at the fuel line like that. It's a flare fitting so the sealing areas are the flare on the fuel line and the mating surface on the inlet housing. Have you inspected both to make sure there aren't any scratches, burs, etc that may result in an issue with the seal?

edit: Ignore the above as I when I read this last night I thought you were having a leak at the flare nut.

Have you checked to make sure the nylon washer is not compromised? It's fairly thin and a small scratch on it or an irregularity on the housing could be a leak source. Some of mine have actually cracked due to becoming brittle with age/heat exposure.

As already posted, permanently attaching the filter housing to the carb body is an option. Over the years I have seen many stripped threads permanently repaired with JB Weld.

Last edited by Fun71; June 30th, 2014 at 01:35 PM.
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Old June 30th, 2014, 07:23 AM
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Originally Posted by tru-blue 442
Greg, some may disagree with me,
but I use teflon tape on the threads
of the filter housing.
All may disagree. Using teflon tape on straight threads is a complete waste. The threads DO NOT seal and are not intended to seal. The plastic washer is the seal for this fuel inlet, and if the threads are not perpendicular to the sealing surface (ie, a cocked helicoil), the plastic gasket will not seal properly. The only possible benefit of the teflon tape is a reduction of thread friction that might allow you to crank down more on the plastic gasket - at the risk of stripping the threads.
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Old June 30th, 2014, 07:32 AM
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There is not much you can do for that, you can remove the filter and if you can get it to seal permanently to never be removed or disturbed again, you can put an inline filter in the system.
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Old June 30th, 2014, 11:29 AM
  #6  
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Originally Posted by oldcutlass
There is not much you can do for that, you can remove the filter and if you can get it to seal permanently to never be removed or disturbed again, you can put an inline filter in the system.
Aye, I reckon that's what I'd do unless you're concerned with being 100% correct and all that. In-line is better anyway.
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Old June 30th, 2014, 02:00 PM
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Not certain from the explanation and do not want to guess which fitting you have. Can you post a picture of the type of fitting?

IIRC the nylon washers were used on the extreme end of the fitting (it snapped in place) and the other style had the washers close to the hex portion, those washers were steel with a coating. Thinking that the wrong type of seal may be used and/or the type of inlet nut could be incorrect?

Is the inlet nut being held so that it does not move while the fuel line is tightened to the inlet nut?

Teflon should not be necessary, but...
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Old June 30th, 2014, 03:55 PM
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[QUOTE=joe_padavano;716535]All may disagree. Using teflon tape on straight threads is a complete waste.

Not sure I follow.
Gasoline has to wick through the threads
to even get to the washer.
I also agree with Sugarbear. There
are 2 types of gasket washer that I
have come across as well. I prefer the
metal type that almost always fits tight
into the carb housing. Did I miss something?

When I have had leaks here, I have always
used the tape and have been good to go.
Just letting Greg know it has ALWAYS worked
for me in the past. I don't see it as a waste.
Heck, what's a little tape anyway?

I also agree with you as well Joe, a cocked
helicoil would never seal properly anyway.

Last edited by tru-blue 442; June 30th, 2014 at 04:03 PM.
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Old June 30th, 2014, 04:13 PM
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Have the carb fixed. Send it to either
http://www.cliffshighperformance.com/index.html or

http://customrebuiltcarburetors.com/

I have used both, great people to deal with.
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Old June 30th, 2014, 06:07 PM
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Thanks for the input. The carb I have now is straight. The fitting doesn't have the nylon washer that fits on the inside edge like the 1st one did. I agree the seal is at the inside- at least on the type with the nylon seal on it. I thought this 2nd fitting had a seal towards the outside by the hex, but after taking it back apart again I see it doesn't. I'm going to go back thru some of the old qjets I've stashed and see what I have. I don't want to jb weld it solid. I hope I have it fixed now. If not I'll take it back apart and post some pics. Thanks again, guys.
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Old June 30th, 2014, 10:16 PM
  #11  
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There should be a seal under the hex on that style.

http://www.carburetion.com/sitesearc...uel%20Fittings

CUD202 is the style you originally had.
CUD1280 sounds like the style on your newer carb.
G1126 may be the seal you need.
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